feuerwerk/tests/core/node-catalog.test.ts

/**
 * One table covering every built-in node that has a `run`: adding a node without a case here
 * fails `covers every built-in node`. The run-less event nodes are listed in `EVENT_NODES`.
 */
import { describe, expect, it } from 'vitest';
import { requireNodeDef } from '../../src/core/commands/require';
import { BUILT_IN_NODES } from '../../src/core/graph/nodes';
import {
  createEmptyGraph,
  type DeclaredPort,
  type GraphLookup,
  NO_LOOKUP,
  type NodeContext,
  type PhysicsControl,
  resolveDef,
  type RunResult,
  type Value,
  worldPositionOf,
} from '../../src/core/graph';
import type { PropertyBag } from '../../src/core/model/Properties';
import { fakeContext, type FakeContext, fakeEntity, fakeHandle, NO_POINTER, runDef } from '../helpers';

interface Case {
  /** What the case demonstrates – becomes the failure message. */
  name: string;
  inputs?: Record<string, Value>;
  params?: PropertyBag;
  context?: Partial<NodeContext>;
  /** Ports the node declares for itself – for the types whose ports are variables it names. */
  ports?: DeclaredPort[];
  /** Expected data outputs, compared exactly. */
  outputs?: Record<string, Value>;
  /** Exec outputs the node would have grown in a graph – only for types whose ports are derived. */
  derivedOutputs?: string[];
  /** Exec inputs grown the same way, and the one the pulse arrives through (`exec` unless said). */
  derivedInputs?: string[];
  entry?: string;
  /** Expected exec continuation; `null` asserts the flow ends here. */
  next?: string | string[] | null;
  /** Expected loop request; `null` asserts the node does not loop. */
  repeat?: RunResult['repeat'] | null;
  /** Expected nested-behavior call; `null` asserts the node calls nothing. */
  call?: RunResult['call'] | null;
  /** Expected elements to test against a Match; `null` asserts the node searches nothing. */
  find?: RunResult['find'] | null;
  /** The project around the graph – for a node whose step is written in another asset. */
  lookup?: GraphLookup;
  /** Assertions on what the node did to the context or to the handles it was given. */
  after?(ctx: FakeContext): void;
}

/** A lookup holding one machine "m" with the given states – what the two state readers name. */
const machineWithStates = (states: { id: string; name: string }[]): GraphLookup => ({
  ...NO_LOOKUP,
  machine: (id) => (id === 'm' ? { name: 'M', states, start: '', transitions: [] } : null),
});

/** A lookup holding one curve "c" (#247): straight up to 1.5 at the middle, back down to 1 at the end. */
const overshootingCurve: GraphLookup = {
  ...NO_LOOKUP,
  curve: (id) =>
    id === 'c'
      ? [
          { x: 0, y: 0 },
          { x: 0.5, y: 1.5 },
          { x: 1, y: 1 },
        ]
      : null,
};

/** A lookup holding one machine "m" with the given transitions – what `State transition` reads. */
const machineLookup = (transitions: { from: string; to: string; name?: string }[]): GraphLookup => ({
  ...NO_LOOKUP,
  machine: (id) =>
    id === 'm'
      ? { name: 'M', states: [], start: '', transitions: transitions.map((t) => ({ name: '', ...t })) }
      : null,
});

const run = (type: string, c: Case): { result: RunResult; ctx: FakeContext } => {
  const ctx = fakeContext(c.context);
  const node = { id: 'n', type, x: 0, y: 0, params: c.params ?? {}, ports: c.ports };
  const registered = c.ports ? resolveDef(node, createEmptyGraph(), NO_LOOKUP)! : requireNodeDef(type);
  const execPorts = (keys: string[] = []) => keys.map((key) => ({ key, label: key, type: 'exec' as const }));
  const def = {
    ...registered,
    inputs: [...execPorts(c.derivedInputs), ...registered.inputs],
    outputs: [...registered.outputs, ...execPorts(c.derivedOutputs)],
  };
  const lookup = c.lookup ?? NO_LOOKUP;
  // A pure reader has no `run`: its outputs are what it answers at the moment they are asked for,
  // which is exactly what the interpreter pulls (see `GraphInterpreter.readAll`).
  const result = def.run
    ? def.run(ctx, c.inputs ?? {}, c.params ?? {}, def, c.entry ?? 'exec', lookup)
    : { outputs: def.read!(ctx, c.params ?? {}, (key) => c.inputs?.[key] ?? null, def, lookup) };
  return { result, ctx };
};

const at = (name: string, x: number, y: number) => ({ ...fakeEntity(name), x, y });
/** At (100, 0) in the world, below a parent that is moved, turned a quarter and doubled. */
const nestedMover = {
  ...at('mover', 0, 0),
  parent: { ...at('frame', 100, 0), props: { rotation: 90, scale: 2 } },
};
/** Its own entity, because Emit's whole effect is the count it leaves on the one it is handed. */
const emitTarget = fakeEntity('Sparks');
/** Their own entity each: the animation nodes leave players on the object they are handed. */
const dancer = fakeEntity('Dancer');
/** An object whose once-reset "swing" has run out and blends back over half a second (#233). */
const swinging = {
  ...fakeEntity('Fighter'),
  animations: [
    {
      animationId: 'swing',
      time: 1,
      playing: true,
      order: 1,
      fade: { seconds: 0.5, elapsed: 0, ended: true },
    },
  ],
};
const swingLookup: GraphLookup = {
  ...NO_LOOKUP,
  animation: (id) => (id === 'swing' ? { frames: 10, fps: 10, playback: 'once-reset' } : null),
};
const packed = fakeEntity('Player');
const painted = fakeHandle({ width: 100, text: '' });

type PhysicsDouble = PhysicsControl & { calls: unknown[][] };
/** Records what the physics nodes ask for; "crate" is the one object with a dynamic body. */
const physicsDouble = (): PhysicsDouble => {
  const calls: unknown[][] = [];
  const has = (target: { id: string }) => target.id === 'crate';
  return {
    calls,
    velocityOf: (target) => (has(target) ? { x: 12, y: -3, angular: 45 } : null),
    setVelocity: (target, x, y) => (calls.push(['setVelocity', target.id, x, y]), has(target)),
    setAngularVelocity: (target, degrees) => (
      calls.push(['setAngularVelocity', target.id, degrees]),
      has(target)
    ),
    applyImpulse: (target, x, y) => (calls.push(['applyImpulse', target.id, x, y]), has(target)),
    setGravity: (x, y) => void calls.push(['setGravity', x, y]),
    jointStateOf: (target) => (target.id === 'hinge' ? { value: 30, speed: -12 } : null),
  };
};
const physicsCalls = (ctx: FakeContext) => (ctx.physics as PhysicsDouble).calls;
const crate = fakeEntity('crate');
/** A tilemap of 4 x 2 cells of 10 units, placed at (100, 50). */
const map = { ...fakeEntity('map', 100), y: 50, props: { columns: 4, rows: 2, tileSize: 10 } };

const pointer = (overrides: Partial<NodeContext['pointer']>): Partial<NodeContext> => ({
  pointer: { ...NO_POINTER, ...overrides },
});

/** Player › (Arm › Hitbox #2), Hitbox #1 – the arm comes first in scene order – and a lone Coin. */
const hero = fakeEntity('Player');
const arm = { ...fakeEntity('Arm'), parent: hero };
const deepBox = { ...fakeEntity('Hitbox'), id: 'hitbox-2', parent: arm };
const nearBox = { ...fakeEntity('Hitbox'), id: 'hitbox-1', parent: hero };
const coins = [fakeEntity('Coin', 0, 'coin'), { ...fakeEntity('Coin', 0, 'coin'), id: 'coin-2' }];
const scene: Partial<NodeContext> = { objects: () => [hero, arm, deepBox, nearBox, ...coins] };

const CASES: Record<string, Case[]> = {
  Branch: [
    { name: 'true takes then', inputs: { condition: true }, next: 'then' },
    { name: 'false takes else', inputs: { condition: false }, next: 'else' },
    { name: 'a non-empty string is true', inputs: { condition: 'yes' }, next: 'then' },
    { name: '"false" as text is false', inputs: { condition: 'false' }, next: 'else' },
  ],
  Sequence: [
    { name: 'on its own it has the one output, and follows it', next: ['a'] },
    { name: 'runs every output it has grown, in order', derivedOutputs: ['b', 'c'], next: ['a', 'b', 'c'] },
  ],
  BehaviorEnd: [
    {
      name: 'hands its inputs back out, which is where the caller reads the result',
      inputs: { hit: true, damage: 7 },
      outputs: { hit: true, damage: 7 },
      next: null,
    },
  ],
  RunBehavior: [
    {
      name: 'asks for the named behavior to run, passing its inputs on',
      inputs: { power: 3 },
      params: { behavior: 'b1' },
      call: { behaviorId: 'b1', inputs: { power: 3 }, entry: 'exec' },
      next: 'exec',
    },
    {
      name: 'names the flow input the call came in by, so the start node leaves through that one',
      params: { behavior: 'b1' },
      entry: 'open',
      call: { behaviorId: 'b1', inputs: {}, entry: 'open' },
      next: 'exec',
    },
    {
      name: 'without a behavior chosen it still continues, calling nothing that exists',
      call: { behaviorId: '', inputs: {}, entry: 'exec' },
      next: 'exec',
    },
  ],
  StateBranch: [
    {
      name: 'in no state yet, the flow leaves along else',
      inputs: { machine: 'm' },
      derivedOutputs: ['s1'],
      next: 'else',
    },
    {
      name: 'follows the output of the current state',
      inputs: { machine: 'm' },
      context: { states: { m: 's1' } },
      derivedOutputs: ['s1', 's2'],
      next: 's1',
    },
    {
      name: 'a state that is not among its outputs (another machine, a deleted state) takes else',
      inputs: { machine: 'm' },
      context: { states: { m: 'gone' } },
      derivedOutputs: ['s1'],
      next: 'else',
    },
    {
      // The point of #58: a machine arriving as a value has no state outputs at all.
      name: 'a machine the graph cannot name has no state outputs, so else is the whole node',
      inputs: { machine: 'm' },
      context: { states: { m: 's1' } },
      next: 'else',
    },
  ],
  SetStateByName: [
    {
      name: 'moves the machine to the state of that name',
      inputs: { machine: 'm', state: 'Open' },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's1' }),
    },
    {
      name: 'a state id names the same state, so a rename cannot break a graph that used the id',
      inputs: { machine: 'm', state: 's1' },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's1' }),
    },
    {
      name: 'a name no state answers to moves nothing and takes "not found"',
      inputs: { machine: 'm', state: 'Ajar' },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      next: 'notFound',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
    {
      name: 'a name two states share is no answer: the graph never picked between them',
      inputs: { machine: 'm', state: 'Open' },
      lookup: machineWithStates([
        { id: 's1', name: 'Open' },
        { id: 's2', name: 'Open' },
      ]),
      next: 'notFound',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
    {
      name: 'without a machine there is nothing to set',
      inputs: { machine: '', state: 'Open' },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      next: 'notFound',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
  ],
  SetState: [
    {
      name: 'puts the machine into the state whose input the flow arrived through',
      inputs: { machine: 'm' },
      derivedInputs: ['s1', 's2'],
      entry: 's2',
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's2' }),
    },
    {
      name: 'arriving through no state input changes nothing',
      inputs: { machine: 'm' },
      derivedInputs: ['s1'],
      entry: 'exec',
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
    {
      name: 'without a machine there is nothing to set',
      inputs: { machine: '' },
      derivedInputs: ['s1'],
      entry: 's1',
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
  ],
  TextureSize: [
    {
      name: "hands out the picture's own pixel size",
      inputs: { texture: 'coin' },
      lookup: { ...NO_LOOKUP, textureSize: (id) => (id === 'coin' ? { w: 8, h: 6 } : null) },
      outputs: { width: 8, height: 6 },
    },
    {
      name: 'no picture is 0 × 0',
      inputs: { texture: '' },
      outputs: { width: 0, height: 0 },
    },
  ],
  AnimationPlaying: [
    {
      name: 'a once-reset pass blending out still runs, for as long as its blend out lasts (#233)',
      inputs: { object: swinging, animation: 'swing' },
      lookup: swingLookup,
      outputs: { playing: true, progress: 1, timeLeft: 0.5 },
    },
    {
      name: 'with no animation named answers for what runs on the object',
      inputs: { object: swinging, animation: '' },
      lookup: swingLookup,
      outputs: { playing: true, progress: 1, timeLeft: 0.5 },
    },
    {
      name: 'another animation is not playing',
      inputs: { object: swinging, animation: 'walk' },
      lookup: swingLookup,
      outputs: { playing: false, progress: 0, timeLeft: 0 },
    },
    {
      name: 'no object plays nothing',
      inputs: { object: null, animation: '' },
      lookup: swingLookup,
      outputs: { playing: false, progress: 0, timeLeft: 0 },
    },
  ],
  AnimationLength: [
    {
      name: 'one pass in seconds: ten frames at 10 fps',
      inputs: { animation: 'swing' },
      lookup: swingLookup,
      outputs: { seconds: 1 },
    },
    { name: 'no animation is 0', inputs: { animation: '' }, outputs: { seconds: 0 } },
  ],
  CurrentState: [
    {
      name: 'names the state the machine is in, and hands out its id as well',
      inputs: { machine: 'm' },
      context: { states: { m: 's1' } },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      outputs: { name: 'Open', id: 's1' },
    },
    {
      name: 'in no state, both outputs are empty',
      inputs: { machine: 'm' },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      outputs: { name: '', id: '' },
    },
    {
      // A state of another machine, or one that was deleted: the id stands, the name is gone.
      name: 'a state the machine does not know keeps its id but has no name',
      inputs: { machine: 'm' },
      context: { states: { m: 'gone' } },
      lookup: machineWithStates([{ id: 's1', name: 'Open' }]),
      outputs: { name: '', id: 'gone' },
    },
  ],
  IsInState: [
    {
      name: 'is true on the current state and false on every other',
      inputs: { machine: 'm' },
      context: { states: { m: 's2' } },
      derivedOutputs: ['s1', 's2'],
      outputs: { s1: false, s2: true },
    },
    {
      name: 'in no state, every output is false rather than unanswered',
      inputs: { machine: 'm' },
      derivedOutputs: ['s1', 's2'],
      outputs: { s1: false, s2: false },
    },
  ],
  StateTransition: [
    {
      name: 'follows the transition of the asked-for name out of the current state',
      inputs: { machine: 'm' },
      params: { transition: 'alarm' },
      context: { states: { m: 's1' } },
      lookup: machineLookup([{ from: 's1', to: 's2', name: 'alarm' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's2' }),
    },
    {
      // The point of naming transitions: one node works from every state that has that name.
      name: 'picks the same name out of whichever state the machine is in',
      inputs: { machine: 'm' },
      params: { transition: 'alarm' },
      context: { states: { m: 'searching' } },
      lookup: machineLookup([
        { from: 'patrolling', to: 'chasing', name: 'alarm' },
        { from: 'chasing', to: 'searching', name: 'lost' },
        { from: 'searching', to: 'chasing', name: 'alarm' },
      ]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 'chasing' }),
    },
    {
      name: 'a name the current state does not carry moves nothing',
      inputs: { machine: 'm' },
      params: { transition: 'lost' },
      context: { states: { m: 's1' } },
      lookup: machineLookup([{ from: 's1', to: 's2', name: 'alarm' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's1' }),
    },
    {
      name: 'two of the name out of one state is no move: the graph never picked between them',
      inputs: { machine: 'm' },
      params: { transition: 'alarm' },
      context: { states: { m: 's1' } },
      lookup: machineLookup([
        { from: 's1', to: 's2', name: 'alarm' },
        { from: 's1', to: 's3', name: 'alarm' },
      ]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's1' }),
    },
    {
      // An unnamed transition is a name too, so a machine nobody named still steps.
      name: 'with no name asked for, follows the one unnamed transition',
      inputs: { machine: 'm' },
      context: { states: { m: 's1' } },
      lookup: machineLookup([{ from: 's1', to: 's2' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's2' }),
    },
    {
      name: 'a state with nothing drawn out of it stays put',
      inputs: { machine: 'm' },
      context: { states: { m: 's2' } },
      lookup: machineLookup([{ from: 's1', to: 's2' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({ m: 's2' }),
    },
    {
      name: 'in no state yet there is nothing to move from',
      inputs: { machine: 'm' },
      lookup: machineLookup([{ from: 's1', to: 's2' }]),
      next: 'exec',
      after: (ctx) => expect(ctx.states).toEqual({}),
    },
  ],
  Repeat: [
    {
      name: 'asks for as many body rounds as it was given, then continues at done',
      inputs: { times: 3 },
      repeat: { port: 'body', index: 'index', times: 3 },
      next: 'done',
    },
    {
      name: 'a fractional count is cut and a negative one runs nothing',
      inputs: { times: -2.7 },
      repeat: { port: 'body', index: 'index', times: 0 },
    },
  ],

  // The rounds, the test and where the flow goes on are the interpreter's: see find-match.test.ts.
  Find: [
    {
      name: 'hands the elements to test and goes on from its Match, not from itself',
      inputs: { list: ['a', 'b'] },
      outputs: { item: null, index: -1 },
      next: null,
      find: ['a', 'b'],
    },
    { name: 'no list tests nothing', inputs: { list: null }, find: [] },
  ],

  // The rounds themselves and the break are the interpreter's: see "For each" in graph.test.ts.
  ForEach: [
    {
      name: 'asks for one body round per element, handing out the elements as item',
      inputs: { list: ['a', 'b'] },
      outputs: { item: null, index: -1, stopped: false },
      repeat: {
        port: 'body',
        index: 'index',
        times: 2,
        items: { port: 'item', values: ['a', 'b'] },
        stopWhen: 'break',
        stopped: 'stopped',
        exhausted: { item: null, index: -1, stopped: false },
      },
      next: 'done',
    },
    {
      name: 'no list runs nothing',
      inputs: { list: null },
      repeat: {
        port: 'body',
        index: 'index',
        times: 0,
        items: { port: 'item', values: [] },
        stopWhen: 'break',
        stopped: 'stopped',
        exhausted: { item: null, index: -1, stopped: false },
      },
    },
  ],

  // Reading needs the interpreter, which asks `read` at the moment: see variable-node.test.ts.
  Variables: [
    {
      name: 'writes the variables switched to Set, each keeping its declared type',
      ports: [
        { key: 'speed', kind: 'number', write: true },
        { key: 'lives', kind: 'number' },
      ],
      inputs: { speed: '250', lives: 9 },
      context: { variables: { speed: 100, lives: 3 } },
      next: 'exec',
      after: (ctx) => expect(ctx.variables).toEqual({ speed: 250, lives: 3 }),
    },
    {
      name: 'without a variable it writes nothing',
      next: 'exec',
      after: (ctx) => expect(ctx.variables).toEqual({ speed: 100 }),
    },
  ],
  Properties: [
    {
      name: 'writes the properties switched to Set, each keeping the type it already had',
      ports: [
        { key: 'width', kind: 'number', write: true },
        { key: 'text', kind: 'text', write: true },
        { key: 'height', kind: 'number' },
      ],
      inputs: { object: painted, width: '250', text: 7 },
      next: 'exec',
      after: () => expect(painted.props).toEqual({ width: 250, text: '7' }),
    },
    {
      name: 'no object is a no-op',
      ports: [{ key: 'width', kind: 'number', write: true }],
      inputs: { object: null, width: 5 },
      next: 'exec',
    },
  ],

  Self: [{ name: 'outputs the behavior object', outputs: { object: fakeContext().self } }],
  Owner: [
    { name: 'outputs the object the behavior is parented to', outputs: { object: fakeContext().owner } },
  ],
  Parent: [
    { name: 'no object has no parent', inputs: { object: null }, outputs: { parent: null } },
    {
      name: 'a top-level object has no parent',
      inputs: { object: fakeHandle({}) },
      outputs: { parent: null },
    },
  ],
  ObjectByName: [
    {
      name: 'asks the context for the name',
      inputs: { name: 'Player' },
      context: { findByName: (name) => (name === 'Player' ? fakeEntity('Player') : null) },
      outputs: { object: fakeEntity('Player') },
    },
    { name: 'an unknown name is null', inputs: { name: 'Ghost' }, outputs: { object: null } },
  ],
  ChildByName: [
    {
      name: 'asks the context below the object it is given',
      inputs: { object: fakeEntity('Player'), name: 'Hitbox' },
      context: {
        childByName: (parent, name) =>
          parent.name === 'Player' && name === 'Hitbox' ? fakeEntity('Hitbox') : null,
      },
      outputs: { child: fakeEntity('Hitbox') },
    },
    {
      name: 'an unknown name is null',
      inputs: { object: fakeEntity('Player'), name: 'Ghost' },
      outputs: { child: null },
    },
    { name: 'no object is null', inputs: { object: null, name: 'Hitbox' }, outputs: { child: null } },
  ],
  LayerOf: [
    {
      name: 'names the layer the context says the object is on (#211)',
      inputs: { object: fakeEntity('Player') },
      context: { collisionLayerOf: (target) => (target.name === 'Player' ? 1 : null) },
      lookup: { ...NO_LOOKUP, collisionLayers: () => ['Ground', 'Ghost'] },
      outputs: { name: 'Ghost', number: 1 },
    },
    {
      name: 'a layer the project has not named goes by its number',
      inputs: { object: fakeEntity('Player') },
      context: { collisionLayerOf: () => 4 },
      lookup: { ...NO_LOOKUP, collisionLayers: () => ['Ground'] },
      outputs: { name: 'Layer 4', number: 4 },
    },
    {
      name: 'an object without a collider is on no layer',
      inputs: { object: fakeEntity('Player') },
      outputs: { name: '', number: -1 },
    },
    { name: 'no object is on no layer', inputs: { object: null }, outputs: { name: '', number: -1 } },
  ],
  RenderLayerOf: [
    {
      name: 'names the render layer the context says the object is drawn on (#305)',
      inputs: { object: fakeEntity('Coin') },
      context: { renderLayerOf: (target) => (target.name === 'Coin' ? 1 : null) },
      lookup: { ...NO_LOOKUP, renderLayers: () => ['Default', 'UI'] },
      outputs: { name: 'UI', number: 1 },
    },
    {
      name: 'a render layer the project has not named goes by its number',
      inputs: { object: fakeEntity('Coin') },
      context: { renderLayerOf: () => 3 },
      lookup: { ...NO_LOOKUP, renderLayers: () => ['Default'] },
      outputs: { name: 'Layer 3', number: 3 },
    },
    {
      name: 'an object that is not drawn is on no render layer',
      inputs: { object: fakeEntity('Cam') },
      outputs: { name: '', number: -1 },
    },
    { name: 'no object is on no render layer', inputs: { object: null }, outputs: { name: '', number: -1 } },
  ],
  ObjectsByName: [
    {
      name: 'every object so named, in scene order',
      inputs: { name: 'Hitbox' },
      context: scene,
      outputs: { objects: [deepBox, nearBox] },
    },
    {
      name: 'none so named is the empty list',
      inputs: { name: 'Ghost' },
      context: scene,
      outputs: { objects: [] },
    },
  ],
  ChildrenByName: [
    {
      name: 'every one below, the nearer level first',
      inputs: { object: hero, name: 'Hitbox' },
      context: scene,
      outputs: { children: [nearBox, deepBox] },
    },
    {
      name: 'nothing above or beside the object',
      inputs: { object: arm, name: 'Hitbox' },
      context: scene,
      outputs: { children: [deepBox] },
    },
    {
      name: 'no object is the empty list',
      inputs: { object: null, name: 'Hitbox' },
      context: scene,
      outputs: { children: [] },
    },
  ],
  Children: [
    {
      name: 'the direct children only',
      inputs: { object: hero, recursive: false },
      context: scene,
      outputs: { children: [arm, nearBox] },
    },
    {
      name: 'recursive: level by level',
      inputs: { object: hero, recursive: true },
      context: scene,
      outputs: { children: [arm, nearBox, deepBox] },
    },
    {
      name: 'a leaf has none',
      inputs: { object: deepBox, recursive: true },
      context: scene,
      outputs: { children: [] },
    },
    { name: 'no object has none', inputs: { object: null }, context: scene, outputs: { children: [] } },
  ],
  ObjectsOfAsset: [
    {
      name: 'every instance of the asset',
      inputs: { asset: 'coin' },
      context: scene,
      outputs: { objects: coins },
    },
    {
      name: 'no asset chosen is the empty list',
      inputs: { asset: '' },
      context: scene,
      outputs: { objects: [] },
    },
  ],
  NameOf: [
    { name: 'reads the name', inputs: { object: fakeEntity('Coin') }, outputs: { name: 'Coin' } },
    { name: 'no object is the empty name', inputs: { object: null }, outputs: { name: '' } },
  ],
  IsAsset: [
    {
      name: 'matches the asset id',
      inputs: { object: fakeEntity('Coin', 0, 'coin'), asset: 'coin' },
      outputs: { result: true },
    },
    {
      name: 'another asset does not match',
      inputs: { object: fakeEntity('Coin', 0, 'coin'), asset: 'gem' },
      outputs: { result: false },
    },
    {
      name: 'no asset chosen never matches',
      inputs: { object: fakeEntity('Coin', 0, 'coin') },
      outputs: { result: false },
    },
  ],
  IsEnabled: [
    { name: 'on by default', inputs: { object: fakeHandle({}) }, outputs: { result: true, own: true } },
    {
      name: 'own switch off',
      inputs: { object: fakeHandle({ enabled: false }) },
      outputs: { result: false, own: false },
    },
    {
      name: 'own switch on but a parent is off – "own" still reports the own switch',
      inputs: { object: fakeHandle({ enabled: true }, fakeHandle({ enabled: false })) },
      outputs: { result: false, own: true },
    },
    { name: 'no object is off', inputs: { object: null }, outputs: { result: false, own: false } },
  ],
  GetPosition: [
    {
      name: 'a top-level object is at its own position',
      inputs: { object: at('A', 10, 20) },
      outputs: { x: 10, y: 20 },
    },
    {
      name: 'a child reports its position local to the parent',
      inputs: { object: { ...at('child', 10, 20), parent: at('parent', 100, 200) } },
      outputs: { x: 10, y: 20 },
    },
    { name: 'no object is the origin', inputs: { object: null }, outputs: { x: 0, y: 0 } },
  ],
  GetWorldPosition: [
    {
      name: 'a top-level object is at its own position',
      inputs: { object: at('A', 10, 20) },
      outputs: { x: 10, y: 20 },
    },
    {
      name: 'a child is at the summed position of its parents',
      inputs: { object: { ...at('child', 10, 20), parent: at('parent', 100, 200) } },
      outputs: { x: 110, y: 220 },
    },
    { name: 'no object is the origin', inputs: { object: null }, outputs: { x: 0, y: 0 } },
  ],
  GetZ: [
    {
      name: 'a child reports its own z and the z summed up with its parents',
      inputs: { object: { ...at('child', 0, 0), z: 2, parent: { ...at('parent', 0, 0), z: 5 } } },
      outputs: { z: 2, worldZ: 7 },
    },
    { name: 'no object is 0', inputs: { object: null }, outputs: { z: 0, worldZ: 0 } },
  ],

  Number: [
    { name: 'outputs its setting', params: { value: 7.5 }, outputs: { value: 7.5 } },
    { name: 'unset is 0', outputs: { value: 0 } },
  ],
  Boolean: [
    { name: 'outputs its setting', params: { value: true }, outputs: { value: true } },
    { name: 'unset is false', outputs: { value: false } },
  ],
  String: [
    { name: 'outputs its setting', params: { value: 'hello' }, outputs: { value: 'hello' } },
    { name: 'unset is empty', outputs: { value: '' } },
  ],
  Texture: [
    { name: 'outputs the id it was set to', params: { value: 'fr-0-1' }, outputs: { value: 'fr-0-1' } },
    { name: 'unset is no picture', outputs: { value: '' } },
  ],
  StateMachine: [
    { name: 'outputs the id it was set to', params: { value: 'sm-1' }, outputs: { value: 'sm-1' } },
    { name: 'unset is no machine', outputs: { value: '' } },
  ],
  Sound: [
    { name: 'outputs the id it was set to', params: { value: 'snd-1' }, outputs: { value: 'snd-1' } },
    { name: 'unset is no sound', outputs: { value: '' } },
  ],
  Scene: [
    { name: 'outputs the id it was set to', params: { value: 'sc-1' }, outputs: { value: 'sc-1' } },
    { name: 'unset is no scene', outputs: { value: '' } },
  ],
  Animation: [
    { name: 'outputs the id it was set to', params: { value: 'anim-1' }, outputs: { value: 'anim-1' } },
    { name: 'unset is no animation', outputs: { value: '' } },
  ],
  Asset: [
    { name: 'outputs the id it was set to', params: { value: 'crate' }, outputs: { value: 'crate' } },
    { name: 'unset is no asset', outputs: { value: '' } },
  ],
  Add: [
    { name: 'adds', inputs: { a: 2, b: 3 }, outputs: { result: 5 } },
    { name: 'numeric text is coerced', inputs: { a: '2', b: 3 }, outputs: { result: 5 } },
  ],
  Subtract: [{ name: 'subtracts', inputs: { a: 2, b: 3 }, outputs: { result: -1 } }],
  Multiply: [{ name: 'multiplies', inputs: { a: 2, b: 3 }, outputs: { result: 6 } }],
  Divide: [
    { name: 'divides', inputs: { a: 6, b: 4 }, outputs: { result: 1.5 } },
    { name: 'division by zero is 0, not Infinity', inputs: { a: 6, b: 0 }, outputs: { result: 0 } },
  ],
  Min: [{ name: 'the smaller one', inputs: { a: 2, b: -3 }, outputs: { result: -3 } }],
  Max: [{ name: 'the larger one', inputs: { a: 2, b: -3 }, outputs: { result: 2 } }],
  Abs: [{ name: 'drops the sign', inputs: { value: -4 }, outputs: { result: 4 } }],
  Sqrt: [
    { name: 'square root', inputs: { value: 9 }, outputs: { result: 3 } },
    { name: 'negative input is 0, not NaN', inputs: { value: -9 }, outputs: { result: 0 } },
  ],
  Clamp: [
    {
      name: 'inside the range passes through',
      inputs: { value: 0.4, min: 0, max: 1 },
      outputs: { result: 0.4 },
    },
    { name: 'above the range', inputs: { value: 5, min: 0, max: 1 }, outputs: { result: 1 } },
    { name: 'below the range', inputs: { value: -5, min: 0, max: 1 }, outputs: { result: 0 } },
  ],
  Lerp: [
    { name: 'linear by default', inputs: { a: 10, b: 20, t: 0.25 }, outputs: { result: 12.5 } },
    {
      name: 'the easings of an animation key: cubic in',
      inputs: { a: 0, b: 8, t: 0.5 },
      params: { ease: 'cubic', direction: 'in' },
      outputs: { result: 1 },
    },
    {
      name: 'quad out',
      inputs: { a: 0, b: 8, t: 0.5 },
      params: { ease: 'quad', direction: 'out' },
      outputs: { result: 6 },
    },
    {
      name: 'a curve without a direction set eases both ways',
      inputs: { a: 0, b: 8, t: 0.25 },
      params: { ease: 'cubic' },
      outputs: { result: 0.5 },
    },
    {
      name: 'step stays at a until t reaches 1',
      inputs: { a: 2, b: 8, t: 0.99 },
      params: { ease: 'step' },
      outputs: { result: 2 },
    },
    {
      name: 'step at t 1 is b',
      inputs: { a: 2, b: 8, t: 1 },
      params: { ease: 'step' },
      outputs: { result: 8 },
    },
    {
      name: 'a direction says nothing for linear',
      inputs: { a: 0, b: 8, t: 0.5 },
      params: { ease: 'linear', direction: 'in' },
      outputs: { result: 4 },
    },
    {
      name: 'quad in-out, slow at both ends',
      inputs: { a: 0, b: 8, t: 0.25 },
      params: { ease: 'quad', direction: 'in-out' },
      outputs: { result: 1 },
    },
    {
      name: 'quad in-out, half way at the middle',
      inputs: { a: 0, b: 8, t: 0.5 },
      params: { ease: 'quad', direction: 'in-out' },
      outputs: { result: 4 },
    },
    {
      name: 'an unknown easing runs linear',
      inputs: { a: 0, b: 8, t: 0.25 },
      params: { ease: 'in' },
      outputs: { result: 2 },
    },
    { name: 't past 1 stops at b', inputs: { a: 3, b: -5, t: 1.2 }, outputs: { result: -5 } },
    {
      name: 't below 0 stops at a',
      inputs: { a: 3, b: -5, t: -0.5 },
      params: { ease: 'quad', direction: 'out' },
      outputs: { result: 3 },
    },
    {
      name: 'along a Curve asset, overshooting b',
      inputs: { a: 0, b: 8, t: 0.5 },
      params: { ease: 'curve', curve: 'c' },
      lookup: overshootingCurve,
      outputs: { result: 12 },
    },
    {
      name: 'along a Curve asset that is gone: linear',
      inputs: { a: 0, b: 8, t: 0.25 },
      params: { ease: 'curve', curve: 'gone' },
      lookup: overshootingCurve,
      outputs: { result: 2 },
    },
  ],
  Floor: [
    { name: 'rounds down', inputs: { value: 2.9 }, outputs: { result: 2 } },
    { name: 'rounds down for negatives too', inputs: { value: -2.1 }, outputs: { result: -3 } },
  ],
  Ceil: [
    { name: 'rounds up', inputs: { value: 2.1 }, outputs: { result: 3 } },
    { name: 'a whole number stays put', inputs: { value: 3 }, outputs: { result: 3 } },
  ],
  Round: [
    { name: 'rounds to nearest', inputs: { value: 2.4 }, outputs: { result: 2 } },
    { name: 'half rounds up', inputs: { value: 2.5 }, outputs: { result: 3 } },
    { name: 'negative half rounds towards zero', inputs: { value: -2.5 }, outputs: { result: -2 } },
  ],
  Modulo: [
    { name: 'remainder', inputs: { a: 125, b: 60 }, outputs: { result: 5 } },
    { name: 'modulo zero is 0, not NaN', inputs: { a: 125, b: 0 }, outputs: { result: 0 } },
  ],
  Random: [
    // The spread is checked in "Random stays inside [min, max)" below.
    { name: 'an empty range always yields min', inputs: { min: 3, max: 3 }, outputs: { result: 3 } },
  ],
  Time: [
    {
      name: 'reports the clock and the frame length from the context',
      context: { time: 12.5, dt: 0.016 },
      outputs: { time: 12.5, dt: 0.016 },
    },
  ],

  ToText: [
    { name: 'formats with decimals', inputs: { value: 12.345, decimals: 1 }, outputs: { text: '12.3' } },
    { name: 'text passes through unformatted', inputs: { value: 'x', decimals: 2 }, outputs: { text: 'x' } },
    { name: 'decimals are clamped to 0…10', inputs: { value: 1, decimals: -5 }, outputs: { text: '1' } },
  ],
  ToNumber: [
    { name: 'reads a text as a number', inputs: { value: '42' }, outputs: { result: 42 } },
    { name: 'a word is 0', inputs: { value: 'twelve' }, outputs: { result: 0 } },
  ],
  Substring: [
    {
      name: 'takes count characters from start',
      inputs: { text: 'abcdef', start: 2, count: 3 },
      outputs: { text: 'cde' },
    },
    {
      name: 'a negative count reaches to the end',
      inputs: { text: 'abcdef', start: 4, count: -1 },
      outputs: { text: 'ef' },
    },
    {
      name: 'asking past the end gives what is there',
      inputs: { text: 'ab', start: 1, count: 10 },
      outputs: { text: 'b' },
    },
  ],

  List: [
    { name: 'hands out the list it was given', params: { value: [1, 2, 3] }, outputs: { value: [1, 2, 3] } },
    { name: 'an unset list is empty, not missing', outputs: { value: [] } },
    {
      name: 'with a type, hands out the items without the mark they carry in the node (#271)',
      params: { structType: 'loot', value: [{ Name: 'Gem', $struct: 'loot' }] },
      outputs: { value: [{ Name: 'Gem' }] },
    },
  ],
  Fill: [
    { name: 'repeats one value', inputs: { value: 0, count: 4 }, outputs: { result: [0, 0, 0, 0] } },
    { name: 'a negative count gives nothing', inputs: { value: 1, count: -3 }, outputs: { result: [] } },
  ],
  Count: [
    { name: 'counts the items', inputs: { list: ['a', 'b'] }, outputs: { count: 2 } },
    { name: 'a lone value counts as one', inputs: { list: 7 }, outputs: { count: 1 } },
  ],
  ItemAt: [
    { name: 'reads by index, counting from 0', inputs: { list: [4, 5, 6], index: 1 }, outputs: { item: 5 } },
    { name: 'past the end is 0, not a crash', inputs: { list: [4], index: 9 }, outputs: { item: 0 } },
  ],
  SetItem: [
    {
      name: 'replaces one item',
      inputs: { list: [1, 2, 3], index: 1, value: 9 },
      outputs: { result: [1, 9, 3] },
    },
    {
      name: 'leaves the list it was given untouched – a graph may hold it elsewhere',
      inputs: { list: Object.freeze([1, 2, 3]), index: 0, value: 9 },
      outputs: { result: [9, 2, 3] },
    },
    {
      name: 'an index outside the list changes nothing',
      inputs: { list: [1, 2], index: 5, value: 9 },
      outputs: { result: [1, 2] },
    },
  ],
  AddItem: [
    { name: 'appends by default', inputs: { list: [1, 2], value: 3 }, outputs: { result: [1, 2, 3] } },
    {
      name: 'inserts before index',
      inputs: { list: [1, 2, 3], value: 9, index: 1 },
      outputs: { result: [1, 9, 2, 3] },
    },
    {
      name: 'index equal to the length appends',
      inputs: { list: [1, 2], value: 9, index: 2 },
      outputs: { result: [1, 2, 9] },
    },
    {
      name: 'an index outside the list appends instead of dropping the value',
      inputs: { list: [1, 2], value: 9, index: 7 },
      outputs: { result: [1, 2, 9] },
    },
    {
      name: 'leaves the list it was given untouched – a graph may hold it elsewhere',
      inputs: { list: Object.freeze([1, 2]), value: 3 },
      outputs: { result: [1, 2, 3] },
    },
    {
      name: 'a list goes in as one item, not joined',
      inputs: { list: [[1]], value: [2, 3] },
      outputs: { result: [[1], [2, 3]] },
    },
    { name: 'an unset list starts empty', inputs: { value: 5 }, outputs: { result: [5] } },
  ],
  SubList: [
    {
      name: 'takes count items from start',
      inputs: { list: [1, 2, 3, 4], start: 1, count: 2 },
      outputs: { result: [2, 3] },
    },
    {
      name: 'asking past the end gives what is there',
      inputs: { list: [1, 2], start: 1, count: 9 },
      outputs: { result: [2] },
    },
  ],
  Concat: [
    { name: 'one list after the other', inputs: { a: [1], b: [2, 3] }, outputs: { result: [1, 2, 3] } },
    { name: 'a lone value joins as one item', inputs: { a: [1], b: 2 }, outputs: { result: [1, 2] } },
  ],
  PackStruct: [
    {
      name: 'bundles its declared inputs into one value',
      inputs: { x: 2, tags: ['a', 'b'] },
      outputs: { value: { x: 2, tags: ['a', 'b'] } },
    },
    { name: 'a node with no fields yet packs nothing', outputs: { value: {} } },
    {
      name: 'an entity packs as the object it is, so a struct can hold one',
      inputs: { who: packed },
      outputs: { value: { who: packed } as never },
    },
  ],
  ExpandStruct: [
    {
      name: 'reads the fields back out, one output each',
      inputs: { value: { x: 2, tags: ['a'] } },
      outputs: { x: 2, tags: ['a'] },
    },
    { name: 'a value that is not a bundle has no fields', inputs: { value: 7 }, outputs: {} },
  ],
  IndexOf: [
    { name: 'finds where a value sits', inputs: { list: [7, 8, 9], value: 8 }, outputs: { index: 1 } },
    { name: 'a value that is not in there is -1', inputs: { list: [7], value: 8 }, outputs: { index: -1 } },
  ],

  FindText: [
    {
      name: 'finds where the search first appears',
      inputs: { text: '..#.#', search: '#' },
      outputs: { index: 2 },
    },
    {
      name: 'text that does not appear is -1',
      inputs: { text: '....', search: '#' },
      outputs: { index: -1 },
    },
  ],
  Join: [
    { name: 'sticks values together as text', inputs: { a: 'Coins: ', b: 3 }, outputs: { text: 'Coins: 3' } },
    {
      name: 'an object joins as its name',
      inputs: { a: '', b: fakeEntity('Coin') },
      outputs: { text: 'Coin' },
    },
  ],
  Equals: [
    { name: 'equal text', inputs: { a: 'a', b: 'a' }, outputs: { result: true } },
    { name: 'a number equals its text form', inputs: { a: 3, b: '3' }, outputs: { result: true } },
    { name: 'objects compare by identity, not by name', inputs: eqNamesakes(), outputs: { result: false } },
    {
      name: 'two numbers ignore float noise',
      inputs: { a: 5.999999999999972, b: 6 },
      outputs: { result: true },
    },
    { name: 'two numbers still tell 6.001 from 6', inputs: { a: 6.001, b: 6 }, outputs: { result: false } },
    // The inline field of an `any` pin is text: a typed 130 against time - late at 130 s.
    {
      name: 'a noisy number equals the typed text 130',
      inputs: { a: 129.99999999999997, b: '130' },
      outputs: { result: true },
    },
    { name: 'empty text is not 0', inputs: { a: 0, b: '' }, outputs: { result: false } },
    { name: 'two texts still compare as text', inputs: { a: '1.0', b: '1' }, outputs: { result: false } },
  ],
  Compare: [
    { name: 'less than', inputs: { a: 1, b: 2 }, params: { op: '<' }, outputs: { result: true } },
    { name: 'greater or equal', inputs: { a: 2, b: 2 }, params: { op: '>=' }, outputs: { result: true } },
    { name: 'not equal', inputs: { a: 2, b: 2 }, params: { op: '!=' }, outputs: { result: false } },
    // time - late after 6 s of summed dt (#224): the noise counts as equal under every operator.
    {
      name: '== ignores float noise',
      inputs: { a: 5.999999999999972, b: 6 },
      params: { op: '==' },
      outputs: { result: true },
    },
    {
      name: '!= ignores float noise',
      inputs: { a: 5.999999999999972, b: 6 },
      params: { op: '!=' },
      outputs: { result: false },
    },
    {
      name: '< ignores float noise',
      inputs: { a: 5.999999999999972, b: 6 },
      params: { op: '<' },
      outputs: { result: false },
    },
    {
      name: '>= ignores float noise',
      inputs: { a: 5.999999999999972, b: 6 },
      params: { op: '>=' },
      outputs: { result: true },
    },
    {
      name: '> ignores float noise',
      inputs: { a: 6.000000000000028, b: 6 },
      params: { op: '>' },
      outputs: { result: false },
    },
    {
      name: '<= ignores float noise',
      inputs: { a: 6.000000000000028, b: 6 },
      params: { op: '<=' },
      outputs: { result: true },
    },
    {
      name: 'the tolerance grows with the values',
      inputs: { a: 1e6, b: 1e6 + 1e-4 },
      params: { op: '==' },
      outputs: { result: true },
    },
    {
      name: 'a real difference stays one',
      inputs: { a: 6.001, b: 6 },
      params: { op: '==' },
      outputs: { result: false },
    },
    {
      name: 'a tiny value still differs from 0',
      inputs: { a: 1e-6, b: 0 },
      params: { op: '>' },
      outputs: { result: true },
    },
    {
      name: 'no operator chosen falls back to the default "<"',
      inputs: { a: 1, b: 2 },
      outputs: { result: true },
    },
  ],
  FirstNotEmpty: [
    {
      name: 'a is taken when it has a value',
      inputs: { a: 'Hero', b: 'Nobody' },
      outputs: { value: 'Hero' },
    },
    { name: 'an unconnected a gives b', inputs: { b: 5 }, outputs: { value: 5 } },
    { name: '0 counts as empty', inputs: { a: 0, b: 5 }, outputs: { value: 5 } },
    { name: 'empty text counts as empty', inputs: { a: '', b: 'x' }, outputs: { value: 'x' } },
    { name: 'false counts as empty', inputs: { a: false, b: true }, outputs: { value: true } },
    { name: 'an empty list counts as empty', inputs: { a: [], b: [1] }, outputs: { value: [1] } },
    { name: 'a position (0, 0) counts as empty', inputs: { a: { x: 0, y: 0 }, b: 3 }, outputs: { value: 3 } },
    {
      name: 'a struct with one value set is kept',
      inputs: { a: { x: 0, y: 2 }, b: 3 },
      outputs: { value: { x: 0, y: 2 } },
    },
    {
      name: 'an object is never empty',
      inputs: { a: fakeEntity('Coin'), b: 1 },
      outputs: { value: fakeEntity('Coin') },
    },
    { name: 'both empty gives b', inputs: { a: '', b: 0 }, outputs: { value: 0 } },
    {
      name: '"nothing there" keeps a 0',
      inputs: { a: 0, b: 5 },
      params: { empty: 'nothing' },
      outputs: { value: 0 },
    },
    {
      name: '"nothing there" keeps a false',
      inputs: { a: false, b: true },
      params: { empty: 'nothing' },
      outputs: { value: false },
    },
    {
      name: '"nothing there" still falls back on empty text',
      inputs: { a: '', b: 'x' },
      params: { empty: 'nothing' },
      outputs: { value: 'x' },
    },
    {
      name: '"nothing there" still falls back on an empty list',
      inputs: { a: [], b: [1] },
      params: { empty: 'nothing' },
      outputs: { value: [1] },
    },
    {
      name: '"nothing there" keeps a position (0, 0)',
      inputs: { a: { x: 0, y: 0 }, b: 3 },
      params: { empty: 'nothing' },
      outputs: { value: { x: 0, y: 0 } },
    },
    {
      name: '"only a missing value" keeps an empty text',
      inputs: { a: '', b: 'x' },
      params: { empty: 'null' },
      outputs: { value: '' },
    },
    {
      name: '"only a missing value" keeps an empty list',
      inputs: { a: [], b: [1] },
      params: { empty: 'null' },
      outputs: { value: [] },
    },
    {
      name: '"only a missing value" still falls back on an unconnected a',
      inputs: { b: 5 },
      params: { empty: 'null' },
      outputs: { value: 5 },
    },
    {
      name: 'an unknown setting behaves like the default',
      inputs: { a: 0, b: 5 },
      params: { empty: 'nonsense' },
      outputs: { value: 5 },
    },
  ],
  Select: [
    {
      name: 'true takes the true input',
      inputs: { condition: true, false: 'Idle', true: 'Walk' },
      outputs: { value: 'Walk' },
    },
    {
      name: 'false takes the false input',
      inputs: { condition: false, false: 'Idle', true: 'Walk' },
      outputs: { value: 'Idle' },
    },
    { name: 'an unconnected condition is false', inputs: { false: 1, true: 2 }, outputs: { value: 1 } },
    {
      name: 'an empty picked input gives null',
      inputs: { condition: true, false: 1 },
      outputs: { value: null },
    },
    {
      name: 'a value is passed on as it is, even an empty one',
      inputs: { condition: false, false: 0, true: 5 },
      outputs: { value: 0 },
    },
  ],
  And: [
    { name: 'both true', inputs: { a: true, b: true }, outputs: { result: true } },
    { name: 'one false', inputs: { a: true, b: false }, outputs: { result: false } },
    { name: 'an unconnected input reads as false', inputs: { a: true }, outputs: { result: false } },
  ],
  Or: [
    { name: 'one true is enough', inputs: { a: false, b: true }, outputs: { result: true } },
    { name: 'both false', inputs: { a: false, b: false }, outputs: { result: false } },
  ],
  Not: [
    { name: 'inverts', inputs: { value: true }, outputs: { result: false } },
    { name: 'inverts the other way', inputs: { value: false }, outputs: { result: true } },
    { name: '"0" as text counts as false', inputs: { value: '0' }, outputs: { result: true } },
  ],

  Length: [
    { name: '3-4-5 triangle', inputs: { x: 3, y: 4 }, outputs: { result: 5 } },
    { name: 'the zero vector has length 0', inputs: { x: 0, y: 0 }, outputs: { result: 0 } },
  ],
  Normalize: [
    {
      name: 'scales to length 1 and reports the old length',
      inputs: { x: 0, y: -4 },
      outputs: { x: 0, y: -1, length: 4 },
    },
    {
      name: 'the zero vector stays zero instead of becoming NaN',
      inputs: { x: 0, y: 0 },
      outputs: { x: 0, y: 0, length: 0 },
    },
  ],
  Distance: [
    {
      name: 'distance between two objects',
      inputs: { a: at('a', 0, 0), b: at('b', 3, 4) },
      outputs: { result: 5 },
    },
    {
      name: 'measures in world units, also below a parent',
      inputs: { a: { ...at('a', 3, 4), parent: at('p', 100, 0) }, b: at('b', 100, 0) },
      outputs: { result: 5 },
    },
    { name: 'a missing object is distance 0', inputs: { a: at('a', 0, 0), b: null }, outputs: { result: 0 } },
  ],
  AxisInput: [
    {
      name: 'one key gives a unit vector',
      context: { isKeyDown: (key) => key === 'ArrowRight' },
      outputs: { x: 1, y: 0, active: true },
    },
    {
      name: 'diagonals are normalized, so they are not faster',
      context: { isKeyDown: (key) => key === 'ArrowRight' || key === 'ArrowDown' },
      // Not Math.SQRT1_2: the node divides by Math.hypot(1, 1), which lands one ulp lower.
      outputs: { x: 1 / Math.hypot(1, 1), y: 1 / Math.hypot(1, 1), active: true },
    },
    {
      name: 'opposite keys cancel out',
      context: { isKeyDown: (key) => key === 'ArrowLeft' || key === 'ArrowRight' },
      outputs: { x: 0, y: 0, active: false },
    },
    { name: 'nothing held is inactive', outputs: { x: 0, y: 0, active: false } },
  ],
  KeyIsDown: [
    {
      name: 'asks the context for the chosen key',
      params: { key: 'a' },
      context: { isKeyDown: (k) => k === 'a' },
      outputs: { down: true },
    },
    {
      name: 'another key is not down',
      params: { key: 'b' },
      context: { isKeyDown: (k) => k === 'a' },
      outputs: { down: false },
    },
    { name: 'no key chosen is never down', context: { isKeyDown: () => true }, outputs: { down: true } },
  ],
  KeyWasPressed: [
    {
      name: 'asks the context for the press of the chosen key',
      params: { key: 'a' },
      context: { wasKeyPressed: (k) => k === 'a', wasKeyReleased: () => true },
      outputs: { pressed: true },
    },
    {
      name: 'another key was not pressed, and a held one is not a press',
      params: { key: 'b' },
      context: { wasKeyPressed: (k) => k === 'a', isKeyDown: () => true },
      outputs: { pressed: false },
    },
  ],
  KeyWasReleased: [
    {
      name: 'asks the context for the release of the chosen key',
      params: { key: 'a' },
      context: { wasKeyReleased: (k) => k === 'a', wasKeyPressed: () => false },
      outputs: { released: true },
    },
    {
      name: 'another key was not released',
      params: { key: 'b' },
      context: { wasKeyReleased: (k) => k === 'a', wasKeyPressed: () => true },
      outputs: { released: false },
    },
  ],
  MousePosition: [
    {
      name: 'reports the pointer in world units',
      context: pointer({ x: 40, y: -20, inside: true }),
      outputs: { x: 40, y: -20, inside: true },
    },
    {
      name: 'outside the camera frame the position is still reported, but "in view" is false',
      context: pointer({ x: 5, y: 5, inside: false }),
      outputs: { x: 5, y: 5, inside: false },
    },
    {
      name: 'through the camera given, where that camera sees the mouse',
      inputs: { camera: fakeEntity('Ui camera') },
      context: {
        ...pointer({ x: 100, y: 50, inside: true }),
        pointerThrough: (camera) =>
          camera.id === 'Ui camera' ? { x: 1050, y: 25, inside: false } : { x: 0, y: 0, inside: true },
      },
      outputs: { x: 1050, y: 25, inside: false },
    },
  ],
  MouseButton: [
    {
      name: 'the frame the button goes down',
      context: pointer({ down: true, pressed: true }),
      outputs: { down: true, pressed: true, released: false },
    },
    {
      name: 'a later frame while it is still held',
      context: pointer({ down: true }),
      outputs: { down: true, pressed: false, released: false },
    },
    {
      name: 'the frame it goes up',
      context: pointer({ released: true }),
      outputs: { down: false, pressed: false, released: true },
    },
  ],
  IsHovered: [
    {
      name: 'the pointer is over the object',
      inputs: { object: fakeEntity('Button') },
      context: { ...pointer({ inside: true }), hitTest: () => true },
      outputs: { result: true },
    },
    {
      name: 'a hit outside the camera frame does not count',
      inputs: { object: fakeEntity('Button') },
      context: { ...pointer({ inside: false }), hitTest: () => true },
      outputs: { result: false },
    },
    {
      name: 'no object is never hovered',
      inputs: { object: null },
      context: { ...pointer({ inside: true }), hitTest: () => true },
      outputs: { result: false },
    },
    {
      name: 'through the camera given, the test is where that camera sees the mouse',
      inputs: { object: fakeEntity('Button'), camera: fakeEntity('Ui camera') },
      context: {
        ...pointer({ x: 100, y: 50, inside: true }),
        pointerThrough: () => ({ x: 1050, y: 25, inside: true }),
        hitTest: (_, x, y) => x === 1050 && y === 25,
      },
      outputs: { result: true },
    },
    {
      name: 'off the picture of the camera given, nothing is hovered',
      inputs: { object: fakeEntity('Button'), camera: fakeEntity('Ui camera') },
      context: {
        ...pointer({ x: 1050, y: 25, inside: true }),
        pointerThrough: () => ({ x: 1050, y: 25, inside: false }),
        hitTest: () => true,
      },
      outputs: { result: false },
    },
  ],
  IsTouching: [
    {
      name: 'asks the context',
      inputs: { a: fakeEntity('a'), b: fakeEntity('b') },
      context: { isTouching: () => true },
      outputs: { result: true },
    },
    {
      name: 'a missing object never touches',
      inputs: { a: fakeEntity('a'), b: null },
      context: { isTouching: () => true },
      outputs: { result: false },
    },
  ],

  Move: [
    {
      name: 'moves by (dx, dy) × scale × dt',
      inputs: { object: at('m', 0, 0), dx: 1, dy: 0, scale: 100, dt: 0.5 },
      next: 'exec',
      outputs: { blockedX: false, blockedY: false, hit: false, normalX: 0, normalY: 0 },
    },
    {
      name: 'with collision it hands on what the move met',
      inputs: { object: at('m', 0, 0), dx: 4, dy: 2, scale: 1, dt: 1 },
      params: { collide: true },
      context: {
        moveAndSlide: (_target: unknown, dx: number, dy: number) => ({
          blockedX: dx === 4,
          blockedY: dy === 3,
          hit: true,
          normal: { x: -1, y: 0 },
        }),
      },
      next: 'exec',
      outputs: { blockedX: true, blockedY: false, hit: true, normalX: -1, normalY: 0 },
    },
    {
      name: 'no object is a no-op that still continues the flow',
      inputs: { object: null, dx: 1, dy: 1 },
      next: 'exec',
      outputs: { blockedX: false, blockedY: false, hit: false, normalX: 0, normalY: 0 },
    },
  ],
  MoveToward: [
    {
      name: 'steps speed × dt toward the point',
      inputs: { object: at('m', 0, 0), x: 10, y: 0, speed: 4, dt: 0.5 },
      next: 'exec',
      outputs: { arrived: false, distance: 8, hit: false },
    },
    {
      name: 'stops on the point instead of running past it',
      inputs: { object: at('m', 0, 0), x: 3, y: 4, speed: 100, dt: 1 },
      next: 'exec',
      outputs: { arrived: true, distance: 0, hit: false },
    },
    {
      name: 'counts the point in world units under a moved, turned parent',
      inputs: { object: nestedMover, x: 100, y: 10, speed: 100, dt: 1 },
      next: 'exec',
      after: () => {
        const world = worldPositionOf(nestedMover);
        expect(world.x).toBeCloseTo(100, 9);
        expect(world.y).toBeCloseTo(10, 9);
      },
    },
    {
      name: 'with collision a solid in the way holds it back and says so',
      inputs: { object: at('m', 0, 0), x: 10, y: 0, speed: 100, dt: 1 },
      params: { collide: true },
      context: {
        moveAndSlide: () => ({ blockedX: true, blockedY: false, hit: true, normal: { x: -1, y: 0 } }),
      },
      next: 'exec',
      outputs: { arrived: false, distance: 10, hit: true },
    },
    {
      name: 'no object is a no-op that still continues the flow',
      inputs: { object: null, x: 1, y: 1 },
      next: 'exec',
      outputs: { arrived: false, distance: 0, hit: false },
    },
  ],
  SetPosition: [
    {
      name: 'places the object and continues',
      inputs: { object: at('p', 0, 0), x: 30, y: -40 },
      next: 'exec',
    },
    { name: 'no object is a no-op', inputs: { object: null, x: 1, y: 1 }, next: 'exec' },
  ],
  SetZ: [
    { name: 'sets the z and continues', inputs: { object: at('z', 0, 0), z: 3 }, next: 'exec' },
    { name: 'no object is a no-op', inputs: { object: null, z: 3 }, next: 'exec' },
  ],
  ApplyForce: [
    {
      name: 'pushes for the length of the frame: force × dt, handed on as an impulse',
      inputs: { object: crate, x: 10, y: -4 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([['applyImpulse', 'crate', 5, -2]]),
    },
    {
      name: 'no object asks nothing and continues',
      inputs: { object: null, x: 10, y: 0 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([]),
    },
    {
      name: 'without physics (the editor run) it continues',
      inputs: { object: crate, x: 1, y: 1 },
      next: 'exec',
    },
  ],
  ApplyImpulse: [
    {
      name: 'kicks the object with the impulse as given',
      inputs: { object: crate, x: 3, y: -4 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([['applyImpulse', 'crate', 3, -4]]),
    },
    { name: 'without physics it continues', inputs: { object: crate, x: 1, y: 1 }, next: 'exec' },
  ],
  SetVelocity: [
    {
      name: 'sets the velocity as given',
      inputs: { object: crate, x: 120, y: -30 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([['setVelocity', 'crate', 120, -30]]),
    },
    { name: 'without physics it continues', inputs: { object: crate, x: 1, y: 1 }, next: 'exec' },
  ],
  SetAngularVelocity: [
    {
      name: 'sets the turning speed in degrees per second',
      inputs: { object: crate, speed: 90 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([['setAngularVelocity', 'crate', 90]]),
    },
    { name: 'without physics it continues', inputs: { object: crate, speed: 90 }, next: 'exec' },
  ],
  GetVelocity: [
    {
      name: 'reads velocity and turning speed',
      inputs: { object: crate },
      context: { physics: physicsDouble() },
      outputs: { x: 12, y: -3, angular: 45 },
    },
    {
      name: 'an object without a dynamic body reads 0',
      inputs: { object: fakeEntity('wall') },
      context: { physics: physicsDouble() },
      outputs: { x: 0, y: 0, angular: 0 },
    },
    { name: 'without physics it reads 0', inputs: { object: crate }, outputs: { x: 0, y: 0, angular: 0 } },
  ],
  JointPosition: [
    {
      name: 'reads how far the joint stands from where it was placed, and how fast',
      inputs: { joint: fakeEntity('hinge') },
      context: { physics: physicsDouble() },
      outputs: { value: 30, speed: -12 },
    },
    {
      name: 'a joint the engine does not read reads 0',
      inputs: { joint: fakeEntity('rope') },
      context: { physics: physicsDouble() },
      outputs: { value: 0, speed: 0 },
    },
    {
      name: 'without physics it reads 0',
      inputs: { joint: fakeEntity('hinge') },
      outputs: { value: 0, speed: 0 },
    },
  ],
  SetGravity: [
    {
      name: 'sets the scene gravity',
      inputs: { x: 0, y: -500 },
      context: { physics: physicsDouble() },
      next: 'exec',
      after: (ctx) => expect(physicsCalls(ctx)).toEqual([['setGravity', 0, -500]]),
    },
    { name: 'without physics it continues', inputs: { x: 0, y: 1 }, next: 'exec' },
  ],
  Raycast: [
    {
      name: 'hands the ray to the context, ignoring the owner, and puts out what it met',
      inputs: { fromX: 10, fromY: 20, dirX: 0, dirY: 1, length: 300 },
      context: {
        raycast: (from, direction, length, options) => {
          expect([from, direction, length, options.ignore?.id, options.triggers]).toEqual([
            { x: 10, y: 20 },
            { x: 0, y: 1 },
            300,
            'owner',
            false,
          ]);
          return {
            object: crate,
            collider: painted,
            point: { x: 10, y: 120 },
            normal: { x: 0, y: -1 },
            distance: 100,
          };
        },
      },
      next: 'exec',
      outputs: {
        hit: true,
        object: crate,
        collider: painted,
        pointX: 10,
        pointY: 120,
        normalX: 0,
        normalY: -1,
        distance: 100,
      },
    },
    {
      name: 'without "Ignore owner" and with "Hit triggers" it says so; a miss puts out nothing',
      inputs: { fromX: 0, fromY: 0, dirX: 1, dirY: 0, length: 50 },
      params: { ignoreOwner: false, triggers: true },
      context: {
        raycast: (_from, _direction, _length, options) => {
          expect([options.ignore, options.triggers]).toEqual([null, true]);
          return null;
        },
      },
      next: 'exec',
      outputs: {
        hit: false,
        object: null,
        collider: null,
        pointX: 0,
        pointY: 0,
        normalX: 0,
        normalY: 0,
        distance: 0,
      },
    },
  ],
  RaycastAll: [
    {
      name: 'puts the hits out as parallel lists, nearest first, and counts them (#157)',
      inputs: { fromX: 10, fromY: 20, dirX: 0, dirY: 1, length: 300, maxHits: 2 },
      context: {
        raycastAll: (from, direction, length, options) => {
          expect([from, direction, length, options.ignore?.id, options.triggers, options.maxHits]).toEqual([
            { x: 10, y: 20 },
            { x: 0, y: 1 },
            300,
            'owner',
            false,
            2,
          ]);
          return [
            {
              object: crate,
              collider: painted,
              point: { x: 10, y: 120 },
              normal: { x: 0, y: -1 },
              distance: 100,
            },
            {
              object: dancer,
              collider: dancer,
              point: { x: 10, y: 220 },
              normal: { x: 0, y: 1 },
              distance: 200,
            },
          ];
        },
      },
      next: 'exec',
      outputs: {
        count: 2,
        // The objects travel as objects, not as their names: that is what a list may carry now.
        objects: [crate, dancer],
        colliders: [painted, dancer],
        pointsX: [10, 10],
        pointsY: [120, 220],
        normalsX: [0, 0],
        normalsY: [-1, 1],
        distances: [100, 200],
      },
    },
    {
      name: 'a ray that meets nothing puts out empty lists and a count of 0',
      inputs: { fromX: 0, fromY: 0, dirX: 1, dirY: 0, length: 50, maxHits: -3 },
      params: { ignoreOwner: false, triggers: true },
      context: {
        raycastAll: (_from, _direction, _length, options) => {
          // A negative "max hits" is no limit at all, the same as 0.
          expect([options.ignore, options.triggers, options.maxHits]).toEqual([null, true, 0]);
          return [];
        },
      },
      next: 'exec',
      outputs: {
        count: 0,
        objects: [],
        colliders: [],
        pointsX: [],
        pointsY: [],
        normalsX: [],
        normalsY: [],
        distances: [],
      },
    },
  ],
  IgnoreOneWay: [
    {
      name: 'asks the context to let the object through for the seconds given',
      inputs: { object: crate, seconds: 0.4 },
      context: { ignoreOneWay: (target, seconds) => expect([target.id, seconds]).toEqual(['crate', 0.4]) },
      next: 'exec',
    },
    { name: 'no object is a no-op that continues', inputs: { object: null, seconds: 1 }, next: 'exec' },
  ],
  TileAt: [
    {
      name: 'asks the context for the cell, floored to whole cells, and says what lies there (#135)',
      inputs: { tilemap: map, layer: 'Ground', cellX: 2.7, cellY: 1 },
      context: {
        tileAt: (target, layer, cell) => {
          expect([target.id, layer, cell]).toEqual(['map', 'Ground', { x: 2, y: 1 }]);
          return 'grass';
        },
      },
      outputs: { tile: 'grass', empty: false },
    },
    {
      name: 'an empty cell, and one the context cannot answer, both read as empty',
      inputs: { tilemap: map, layer: '', cellX: 0, cellY: 0 },
      context: { tileAt: () => null },
      outputs: { tile: '', empty: true },
    },
    { name: 'no tilemap is an empty cell', inputs: { tilemap: null }, outputs: { tile: '', empty: true } },
  ],
  SetTile: [
    {
      name: 'hands the cell and the tile to the context and says whether it took them',
      inputs: { tilemap: map, layer: 'Ground', cellX: 3, cellY: 4.5, tile: 'door' },
      context: {
        setTile: (target, layer, cell, tile) => {
          expect([target.id, layer, cell, tile]).toEqual(['map', 'Ground', { x: 3, y: 4 }, 'door']);
          return true;
        },
      },
      next: 'exec',
      outputs: { done: true },
    },
    {
      name: 'no tilemap sets nothing and continues',
      inputs: { tilemap: null },
      next: 'exec',
      outputs: { done: false },
    },
  ],
  WorldToCell: [
    {
      name: 'finds the cell under a world point of a moved map, and whether it is on the grid',
      // 4 x 2 cells of 10 around (100, 50): the grid runs from (80, 40) to (120, 60).
      inputs: { tilemap: map, x: 95, y: 55 },
      context: { isTilemap: () => true },
      outputs: { cellX: 1, cellY: 1, inside: true },
    },
    {
      name: 'a point off the grid still names a cell, but not an inside one',
      inputs: { tilemap: map, x: 75, y: 45 },
      context: { isTilemap: () => true },
      outputs: { cellX: -1, cellY: 0, inside: false },
    },
    {
      name: 'something that is no tilemap has no cells',
      inputs: { tilemap: map, x: 95, y: 55 },
      outputs: { cellX: 0, cellY: 0, inside: false },
    },
  ],
  CellToWorld: [
    {
      name: 'puts out the middle of the cell in world units',
      inputs: { tilemap: map, cellX: 1, cellY: 1 },
      context: { isTilemap: () => true },
      outputs: { x: 95, y: 55 },
    },
    { name: 'no tilemap answers the origin', inputs: { tilemap: null, cellX: 1 }, outputs: { x: 0, y: 0 } },
  ],
  Tile: [{ name: 'hands out the tile chosen', params: { value: 'door' }, outputs: { value: 'door' } }],
  Spawn: [
    {
      name: 'places the asset that arrives on its input, local to the parent',
      inputs: { asset: 'crate', x: 1, y: 2, z: 3, parent: fakeEntity('Box') },
      context: {
        spawn: (assetId, position, parent) =>
          assetId === 'crate' &&
          position.x === 1 &&
          position.y === 2 &&
          position.z === 3 &&
          parent?.name === 'Box'
            ? fakeEntity('Crate')
            : null,
      },
      next: 'exec',
      outputs: { object: fakeEntity('Crate') },
    },
    {
      name: 'no asset chosen logs a hint and continues with no object',
      next: 'exec',
      outputs: { object: null },
      after: (ctx) => expect(ctx.logs).toEqual(['Spawn: no asset selected']),
    },
  ],
  AddJoint: [
    {
      name: 'places the picked joint on the object at (x, y), connected to the other',
      inputs: { jointAsset: 'rope', object: fakeEntity('Box'), connected: fakeEntity('Hook'), x: 4, y: -6 },
      context: {
        addJoint: (assetId, owner, connected, at) =>
          assetId === 'rope' &&
          owner.name === 'Box' &&
          connected?.name === 'Hook' &&
          at.x === 4 &&
          at.y === -6
            ? fakeEntity('Rope')
            : null,
      },
      next: 'exec',
      outputs: { joint: fakeEntity('Rope') },
    },
    {
      name: 'hands the scene on as null when nothing is connected',
      inputs: { jointAsset: 'rope', object: fakeEntity('Box'), connected: null },
      context: { addJoint: (_asset, _owner, connected) => (connected === null ? fakeEntity('Rope') : null) },
      next: 'exec',
      outputs: { joint: fakeEntity('Rope') },
    },
    {
      name: 'without a picked joint places nothing and says so',
      inputs: { jointAsset: '', object: fakeEntity('Box') },
      next: 'exec',
      outputs: { joint: null },
      after: (ctx) => expect(ctx.logs).toEqual(['Add joint: no joint selected']),
    },
    {
      name: 'an asset that is no joint places nothing and says so',
      inputs: { jointAsset: 'crate', object: fakeEntity('Box') },
      next: 'exec',
      outputs: { joint: null },
      after: (ctx) => expect(ctx.logs).toEqual(['Add joint: asset crate is no joint']),
    },
  ],
  Destroy: [
    {
      name: 'no object is a no-op that still continues the flow',
      inputs: { object: null },
      next: 'exec',
    },
  ],
  Emit: [
    {
      name: 'no source is a no-op that still continues the flow',
      inputs: { source: null },
      next: 'exec',
    },
    {
      name: 'counts a pulse on the source it is given',
      inputs: { source: emitTarget },
      next: 'exec',
      after: () => expect(emitTarget.emits).toBe(1),
    },
  ],
  PlayAnimation: [
    {
      name: 'no object is a no-op that still continues the flow',
      inputs: { object: null, animation: 'anim-1' },
      next: 'exec',
    },
    {
      name: 'starts a player on the object, and a second play leaves it running',
      inputs: { object: dancer, animation: 'anim-1' },
      next: 'exec',
      after: () => {
        expect(dancer.animations).toMatchObject([{ animationId: 'anim-1', time: 0, playing: true }]);
      },
    },
  ],
  PauseAnimation: [
    {
      name: 'holds the player where it stands',
      inputs: { object: dancer, animation: 'anim-1' },
      next: 'exec',
      after: () => expect(dancer.animations?.map((p) => p.playing)).toEqual([false]),
    },
  ],
  StopAnimation: [
    {
      name: 'with no animation named ends every player on the object',
      inputs: { object: dancer, animation: '' },
      next: 'exec',
      after: () => expect(dancer.animations).toEqual([]),
    },
  ],
  PlaySound: [
    {
      name: 'no sound is a no-op that still continues the flow',
      inputs: { sound: '', volume: 1, loop: '' },
      next: 'exec',
      outputs: { voice: 0, length: 0, tail: 0 },
      after: (ctx) => expect(ctx.played).toEqual([]),
    },
    {
      name: 'hands the id on with the volume and loop it was given, and gives out the voice (#315), its length and its tail (#324)',
      inputs: { sound: 'snd-1', volume: 0.5, loop: 'true' },
      next: 'exec',
      // The fake context rings a voice on for its number in tenths of a second.
      outputs: { voice: 1, length: 0.25, tail: 0.35 },
      // What the two mean – a factor on the asset's volume, an answer that overrules its loop
      // flag – is the BehaviorSystem's to resolve, since only it holds the project (see
      // `sounds.test.ts`).
      after: (ctx) =>
        expect(ctx.played).toEqual([
          { assetId: 'snd-1', volume: 0.5, loop: true, detached: false, fx: '', fxParams: {}, tempo: 120 },
        ]),
    },
    {
      name: 'hands on its tempo for a Delay synced to beats, held to 20 to 400 BPM (#332)',
      inputs: { sound: 'snd-1', volume: 1, loop: '', tempo: 1000 },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.tempo).toBe(400),
    },
    {
      name: 'detached says the voice is nobody’s, so destroying this object leaves it playing',
      inputs: { sound: 'snd-1', volume: 1, loop: '', detached: true },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.detached).toBe(true),
    },
    {
      name: 'saying nothing about looping leaves the answer to the asset',
      inputs: { sound: 'snd-1', volume: 1, loop: '' },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.loop).toBeUndefined(),
    },
    {
      name: 'off is an answer of its own, not the absence of one',
      inputs: { sound: 'snd-1', volume: 1, loop: 'false' },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.loop).toBe(false),
    },
    {
      name: 'hands on the sound FX it names (#311)',
      inputs: { sound: 'snd-1', volume: 1, loop: '', fx: 'fx-1' },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.fx).toBe('fx-1'),
    },
    {
      name: 'hands on the numbers of its fx params, and nothing for what is no bundle',
      inputs: { sound: 'snd-1', volume: 1, loop: '', fx: 'fx-1', fxParams: { depth: -12, name: 'x' } },
      next: 'exec',
      after: (ctx) => expect(ctx.played[0]?.fxParams).toEqual({ depth: -12 }),
    },
  ],
  PlayNote: [
    {
      name: 'no instrument is a no-op that still continues the flow',
      inputs: { instrument: '', note: 60 },
      next: 'exec',
      outputs: { voice: 0 },
      after: (ctx) => expect(ctx.notes).toEqual([]),
    },
    {
      name: 'hands the instrument on with its note, velocity, volume and duration, and gives out the voice (#331)',
      inputs: {
        instrument: 'ins-1',
        note: 64,
        velocity: 0.5,
        volume: 0.8,
        duration: 0.25,
        fxParams: { cut: 2 },
      },
      next: 'exec',
      outputs: { voice: 1 },
      after: (ctx) =>
        expect(ctx.notes).toEqual([
          {
            instrumentId: 'ins-1',
            note: 64,
            velocity: 0.5,
            volume: 0.8,
            duration: 0.25,
            detached: false,
            instrumentParams: { cut: 2 },
            tempo: 120,
          },
        ]),
    },
    {
      name: 'hands on its tempo for a Delay synced to beats (#332)',
      inputs: { instrument: 'ins-1', note: 60, tempo: 90 },
      next: 'exec',
      after: (ctx) => expect(ctx.notes[0]?.tempo).toBe(90),
    },
  ],
  InstrumentParameterValues: [
    {
      name: 'bundles its picked parameters as numbers, as for a sound FX',
      ports: [{ key: 'cut', kind: 'number' }],
      inputs: { cut: '0.5' },
      outputs: { params: { cut: 0.5 } },
    },
    { name: 'with none picked the bundle is empty', outputs: { params: {} } },
  ],
  PlayPattern: [
    {
      name: 'no pattern is a no-op that still continues the flow',
      inputs: { pattern: '' },
      next: 'exec',
      outputs: { playback: 0 },
      after: (ctx) => expect(ctx.patterns).toEqual([]),
    },
    {
      name: 'hands the pattern on with its volume, looping and owned unless asked otherwise',
      inputs: { pattern: 'pat-1', volume: 0.5, loop: true },
      next: 'exec',
      outputs: { playback: 1 },
      after: (ctx) =>
        expect(ctx.patterns).toEqual([{ patternId: 'pat-1', volume: 0.5, loop: true, detached: false }]),
    },
    {
      name: 'plays once and detached when asked to',
      inputs: { pattern: 'pat-1', loop: false, detached: true },
      next: 'exec',
      after: (ctx) => expect(ctx.patterns[0]).toMatchObject({ loop: false, detached: true }),
    },
  ],
  StopPattern: [
    {
      name: 'stops the pattern it names, letting its notes ring when asked to',
      inputs: { pattern: 'pat-1', letRing: true },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['pattern pat-1 (let ring)']),
    },
    {
      name: 'naming none stops every pattern',
      inputs: { pattern: '' },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['pattern ']),
    },
    {
      name: 'with a playback connected stops only that one, whatever pattern is named',
      inputs: { pattern: 'pat-1', playback: 4 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['voice 4']),
    },
    {
      name: 'a connected playback of 0 – a Play pattern that played nothing – stops nothing',
      inputs: { pattern: 'pat-1', playback: 0 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual([]),
    },
  ],
  PlaySong: [
    {
      name: 'no song is a no-op that still continues the flow',
      inputs: { song: '' },
      next: 'exec',
      outputs: { playback: 0 },
      after: (ctx) => expect(ctx.songs).toEqual([]),
    },
    {
      name: 'hands the song on with its volume and fade in, looping and owned unless asked otherwise',
      inputs: { song: 'song-1', volume: 0.5, fadeIn: 2, loop: true },
      next: 'exec',
      outputs: { playback: 1 },
      after: (ctx) =>
        expect(ctx.songs).toEqual([
          { songId: 'song-1', volume: 0.5, fadeIn: 2, loop: true, detached: false },
        ]),
    },
    {
      name: 'plays once and detached when asked to',
      inputs: { song: 'song-1', volume: 1, fadeIn: 0, loop: false, detached: true },
      next: 'exec',
      after: (ctx) => expect(ctx.songs[0]).toMatchObject({ loop: false, detached: true }),
    },
  ],
  StopSong: [
    {
      name: 'stops the song it names over its fade out',
      inputs: { song: 'song-1', fadeOut: 1.5 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['song song-1 (fade 1.5)']),
    },
    {
      name: 'naming none stops every song',
      inputs: { song: '', fadeOut: 0 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['song  (fade 0)']),
    },
    {
      name: 'with a playback connected stops only that one, whatever song is named',
      inputs: { song: 'song-1', playback: 4, fadeOut: 2 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['playback 4 (fade 2)']),
    },
    {
      name: 'a connected playback of 0 – a Play song that played nothing – stops nothing',
      inputs: { song: 'song-1', playback: 0 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual([]),
    },
  ],
  SoundFxParameters: [
    {
      name: 'bundles its picked parameters as numbers',
      ports: [
        { key: 'depth', kind: 'number' },
        { key: 'loud', kind: 'number' },
      ],
      inputs: { depth: '-12', loud: 3 },
      outputs: { params: { depth: -12, loud: 3 } },
    },
    { name: 'with none picked the bundle is empty', outputs: { params: {} } },
  ],
  LoadScene: [
    {
      name: 'asks the context for the scene it names',
      inputs: { scene: 'sc-1' },
      next: 'exec',
      after: (ctx) => expect(ctx.loaded).toEqual(['sc-1']),
    },
    {
      name: 'naming no scene asks for nothing, and the flow carries on',
      inputs: { scene: '' },
      next: 'exec',
      after: (ctx) => expect(ctx.loaded).toEqual([]),
    },
  ],
  StopSound: [
    {
      name: 'silences the sound it names',
      inputs: { sound: 'snd-1' },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['snd-1']),
    },
    {
      name: 'naming none asks for everything',
      inputs: { sound: '' },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['']),
    },
    {
      name: 'lets the echoes of the sound ring when asked to (#324)',
      inputs: { sound: 'snd-1', letRing: true },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['snd-1 (let ring)']),
    },
    {
      name: 'with a voice connected silences only that one, whatever sound is named',
      inputs: { sound: 'snd-1', voice: 3, letRing: true },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual(['voice 3 (let ring)']),
    },
    {
      name: 'a connected voice of 0 – a Play sound that played nothing – silences nothing, not everything',
      inputs: { sound: '', voice: 0 },
      next: 'exec',
      after: (ctx) => expect(ctx.silenced).toEqual([]),
    },
  ],
  SetSoundFxParameters: [
    {
      name: 'hands the numbers of the bundle to the voice it is given',
      inputs: { voice: 4, fxParams: { depth: 3, label: 'x' } },
      next: 'exec',
      after: (ctx) =>
        expect(ctx.tuned).toEqual([{ voice: 4, fxParams: { depth: 3 }, time: 0, ease: 'linear' }]),
    },
    {
      name: 'hands on the time the values take to get there',
      inputs: { voice: 4, fxParams: { depth: -64 }, time: 1.28 },
      next: 'exec',
      after: (ctx) =>
        expect(ctx.tuned).toEqual([{ voice: 4, fxParams: { depth: -64 }, time: 1.28, ease: 'linear' }]),
    },
    {
      name: 'a time below 0 is a quick glide',
      inputs: { voice: 4, fxParams: { depth: 3 }, time: -2 },
      next: 'exec',
      after: (ctx) =>
        expect(ctx.tuned).toEqual([{ voice: 4, fxParams: { depth: 3 }, time: 0, ease: 'linear' }]),
    },
    {
      name: 'hands on the easing the values take: a curve with its direction as a share of the way',
      inputs: { voice: 4, fxParams: { depth: 3 }, time: 1 },
      params: { ease: 'cubic', direction: 'in' },
      next: 'exec',
      after: (ctx) => {
        const ease = ctx.tuned[0]!.ease;
        expect(typeof ease === 'function' && [ease(0), ease(0.5), ease(1)]).toEqual([0, 0.125, 1]);
      },
    },
    {
      name: 'step is handed on by name, the clock jumps at the end',
      inputs: { voice: 4, fxParams: { depth: 3 }, time: 1 },
      params: { ease: 'step' },
      next: 'exec',
      after: (ctx) => expect(ctx.tuned[0]!.ease).toBe('step'),
    },
    {
      name: 'along a Curve asset, as a share that may overshoot',
      inputs: { voice: 4, fxParams: { depth: 3 }, time: 1 },
      params: { ease: 'curve', curve: 'c' },
      lookup: overshootingCurve,
      next: 'exec',
      after: (ctx) => {
        const ease = ctx.tuned[0]!.ease;
        expect(typeof ease === 'function' && ease(0.5)).toBeCloseTo(1.5, 6);
      },
    },
    {
      name: 'a Curve asset that is gone is linear',
      inputs: { voice: 4, fxParams: { depth: 3 }, time: 1 },
      params: { ease: 'curve', curve: 'gone' },
      lookup: overshootingCurve,
      next: 'exec',
      after: (ctx) => expect(ctx.tuned[0]!.ease).toBe('linear'),
    },
    {
      name: 'voice 0 – nothing was played – reaches nothing, and the flow carries on',
      inputs: { voice: 0, fxParams: { depth: 3 } },
      next: 'exec',
      after: (ctx) => expect(ctx.tuned).toEqual([]),
    },
  ],
  Log: [
    {
      name: 'logs its message and continues',
      inputs: { message: 'hi' },
      next: 'exec',
      after: (ctx) => expect(ctx.logs).toEqual(['hi']),
    },
    {
      name: 'an object logs as its name',
      inputs: { message: fakeEntity('Coin') },
      next: 'exec',
      after: (ctx) => expect(ctx.logs).toEqual(['Coin']),
    },
  ],
  StopGame: [{ name: 'ends play and the flow', next: null, after: (ctx) => expect(ctx.stopped).toBe(true) }],
  RestartGame: [{ name: 'ends the flow – the world restarts before the next tick', next: null }],
  PauseGame: [
    { name: 'pauses the game and flows on', next: 'exec', after: (ctx) => expect(ctx.paused).toBe(true) },
  ],
  ResumeGame: [
    {
      name: 'lets a paused game run on and flows on',
      context: { paused: true } as Partial<NodeContext>,
      next: 'exec',
      after: (ctx) => expect(ctx.paused).toBe(false),
    },
  ],
  IsGamePaused: [
    { name: 'false while the game runs', outputs: { paused: false } },
    {
      name: 'true while it is paused',
      context: { paused: true } as Partial<NodeContext>,
      outputs: { paused: true },
    },
  ],
  SetTimeScale: [
    {
      name: 'sets the scale and flows on',
      inputs: { scale: 0.5 },
      next: 'exec',
      after: (ctx) => expect(ctx.scale).toBe(0.5),
    },
    {
      name: '0 freezes the game',
      inputs: { scale: 0 },
      next: 'exec',
      after: (ctx) => expect(ctx.scale).toBe(0),
    },
    {
      name: 'a negative scale is 0 – time never runs backwards',
      inputs: { scale: -2 },
      after: (ctx) => expect(ctx.scale).toBe(0),
    },
  ],
  TimeScale: [
    {
      name: 'answers the scale the run goes at',
      context: { scale: 0.25 } as Partial<NodeContext>,
      outputs: { scale: 0.25 },
    },
  ],
};

/** Two distinct handles that share a name – `Equals` must still tell them apart. */
function eqNamesakes(): Record<string, Value> {
  return { a: fakeEntity('Coin'), b: fakeEntity('Coin') };
}

/**
 * Nodes without a `run`: only observable through a running world, since the BehaviorSystem
 * seeds their outputs. The value names the test that drives each one.
 */
const EVENT_NODES: Record<string, string> = {
  BehaviorStart: 'nested-behavior.test.ts',
  OnBehavior: 'on-behavior.test.ts',
  OnStart: 'graph.test.ts',
  OnEnable: 'behavior-events.test.ts',
  OnUpdate: 'graph.test.ts',
  OnFixedUpdate: 'fixed-update.test.ts',
  OnDisable: 'behavior-events.test.ts',
  OnDestroy: 'behavior-events.test.ts',
  OnKeyDown: 'behavior-events.test.ts',
  OnKeyUp: 'behavior-events.test.ts',
  OnKeyHeld: 'behavior-events.test.ts',
  OnTimer: 'behavior-events.test.ts',
  OnCollisionEnter: 'collider.test.ts',
  OnCollisionStay: 'behavior-events.test.ts',
  OnCollisionExit: 'collider.test.ts',
  OnClick: 'nodes.test.ts',
  OnMouseWheel: 'clip-areas.test.ts',
  OnAnimationFinished: 'animation.test.ts',
  OnStateEntered: 'state-machine.test.ts',
  OnStateExited: 'state-machine.test.ts',
};

/** A node that ends the block another one opens never runs itself – the opener runs it (`Match`). */
const closesBlock = (type: string) => BUILT_IN_NODES.some((def) => def.opens?.type === type);

describe('node catalog', () => {
  it('covers every built-in node', () => {
    const uncovered = BUILT_IN_NODES.filter((def) =>
      (def.run ?? def.read) ? !CASES[def.type] : !EVENT_NODES[def.type] && !closesBlock(def.type),
    ).map((def) => def.type);
    expect(uncovered).toEqual([]);
  });

  it('lists exactly the nodes that neither run nor read as events', () => {
    const runless = BUILT_IN_NODES.filter((def) => !def.run && !def.read && !closesBlock(def.type)).map(
      (def) => def.type,
    );
    expect(Object.keys(EVENT_NODES).sort()).toEqual(runless.sort());
  });

  it('declares well-formed ports and settings', () => {
    for (const def of BUILT_IN_NODES) {
      const keys = [...def.inputs, ...def.outputs].map((p) => p.key);
      expect(def.label, `${def.type} has a label`).not.toBe('');
      expect(def.description, `${def.type} has a description`).not.toBe('');
      // Keys are unique per side, but may repeat across sides (Normalize reads and writes x/y).
      expect(new Set(def.inputs.map((p) => p.key)).size, `${def.type} input keys unique`).toBe(
        def.inputs.length,
      );
      expect(new Set(def.outputs.map((p) => p.key)).size, `${def.type} output keys unique`).toBe(
        def.outputs.length,
      );
      expect(
        keys.every((k) => k !== ''),
        `${def.type} has no empty port key`,
      ).toBe(true);
      for (const param of def.params) {
        expect(param.default, `${def.type}.${param.key} has a default`).toBeDefined();
      }
    }
  });
});

for (const [type, cases] of Object.entries(CASES)) {
  describe(type, () => {
    for (const c of cases) {
      it(c.name, () => {
        const { result, ctx } = run(type, c);
        if (c.outputs) expect(result.outputs ?? {}).toEqual(c.outputs);
        if (c.next !== undefined) expect(result.next ?? null).toEqual(c.next);
        if (c.repeat !== undefined) expect(result.repeat ?? null).toEqual(c.repeat);
        if (c.call !== undefined) expect(result.call ?? null).toEqual(c.call);
        if (c.find !== undefined) expect(result.find ?? null).toEqual(c.find);
        c.after?.(ctx);
      });
    }
  });
}

describe('action nodes write through to the object they are given', () => {
  it('Move applies dx/dy × scale × dt', () => {
    const target = at('m', 0, 0);
    runDef('Move', fakeContext(), { object: target, dx: 1, dy: -2, scale: 100, dt: 0.5 }, {});
    expect({ x: target.x, y: target.y }).toEqual({ x: 50, y: -100 });
  });

  it('SetPosition places the object absolutely', () => {
    const target = at('p', 10, 10);
    runDef('SetPosition', fakeContext(), { object: target, x: 30, y: -40 }, {});
    expect({ x: target.x, y: target.y }).toEqual({ x: 30, y: -40 });
  });

  it('SetZ sets only the z', () => {
    const target = { ...at('z', 10, 20), z: 1 };
    runDef('SetZ', fakeContext(), { object: target, z: -4 }, {});
    expect({ x: target.x, y: target.y, z: target.z }).toEqual({ x: 10, y: 20, z: -4 });
  });

  it('Destroy hands the object to the context, children and all unless told to keep them', () => {
    const removed: string[] = [];
    const moved = [fakeEntity('Lid'), fakeEntity('Nail')];
    const ctx = fakeContext({
      destroy: (target, keepChildren) => {
        removed.push(`${target.name} ${keepChildren}`);
        return keepChildren ? moved : [];
      },
    });
    expect(runDef('Destroy', ctx, { object: fakeEntity('Coin') }, {}).outputs).toEqual({ children: [] });
    const kept = runDef('Destroy', ctx, { object: fakeEntity('Crate'), keepChildren: true }, {});
    expect(kept.outputs).toEqual({ children: moved });
    expect(removed).toEqual(['Coin false', 'Crate true']);
  });

  it('RestartGame asks the context for a restart', () => {
    let restarted = false;
    const ctx = fakeContext({
      restart: () => {
        restarted = true;
      },
    });
    runDef('RestartGame', ctx, {}, {});
    expect(restarted).toBe(true);
  });

  it('Random stays inside [min, max) over many draws', () => {
    const ctx = fakeContext();
    const draws = Array.from(
      { length: 200 },
      () => runDef('Random', ctx, { min: 5, max: 10 }, {}).outputs!.result as number,
    );
    expect(draws.every((n) => n >= 5 && n < 10)).toBe(true);
    // Not a constant: a generator stuck on one value would pass the range check above.
    expect(new Set(draws).size).toBeGreaterThan(1);
  });
});