test: add child registration integration tests

32 tests covering registerChild, getChildren, deregistration, edge cases.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

test/childRegistration.test.js

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+const ChildRegistrationUtils = require('../src/helper/childRegistrationUtils');
+const { POSITIONS } = require('../src/constants/positions');
+
+// ── Helpers ──────────────────────────────────────────────────────────────────
+
+/** Create a minimal mock parent (mainClass) that ChildRegistrationUtils expects. */
+function createMockParent(opts = {}) {
+  return {
+    child: {},
+    logger: {
+      debug: jest.fn(),
+      info: jest.fn(),
+      warn: jest.fn(),
+      error: jest.fn(),
+    },
+    // optionally provide a registerChild callback so the utils can delegate
+    registerChild: opts.registerChild || undefined,
+    ...opts,
+  };
+}
+
+/** Create a minimal mock child node with the given overrides. */
+function createMockChild(overrides = {}) {
+  const defaults = {
+    config: {
+      general: {
+        id: overrides.id || 'child-1',
+        name: overrides.name || 'TestChild',
+      },
+      functionality: {
+        softwareType: overrides.softwareType !== undefined ? overrides.softwareType : 'measurement',
+        positionVsParent: overrides.position || POSITIONS.UPSTREAM,
+      },
+      asset: {
+        category: overrides.category || 'sensor',
+        type: overrides.assetType || 'pressure',
+      },
+    },
+    measurements: overrides.measurements || null,
+  };
+  // allow caller to add extra top-level props
+  return { ...defaults, ...(overrides.extra || {}) };
+}
+
+// ── Tests ────────────────────────────────────────────────────────────────────
+
+describe('ChildRegistrationUtils', () => {
+  let parent;
+  let utils;
+
+  beforeEach(() => {
+    parent = createMockParent();
+    utils = new ChildRegistrationUtils(parent);
+  });
+
+  // ── Construction ─────────────────────────────────────────────────────────
+  describe('constructor', () => {
+    it('should store a reference to the mainClass', () => {
+      expect(utils.mainClass).toBe(parent);
+    });
+
+    it('should initialise with an empty registeredChildren map', () => {
+      expect(utils.registeredChildren.size).toBe(0);
+    });
+
+    it('should use the parent logger', () => {
+      expect(utils.logger).toBe(parent.logger);
+    });
+  });
+
+  // ── registerChild ────────────────────────────────────────────────────────
+  describe('registerChild()', () => {
+    it('should register a child and store it in the internal map', async () => {
+      const child = createMockChild();
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(utils.registeredChildren.size).toBe(1);
+      expect(utils.registeredChildren.has('child-1')).toBe(true);
+    });
+
+    it('should store softwareType, position and timestamp in the registry entry', async () => {
+      const child = createMockChild({ softwareType: 'machine' });
+      const before = Date.now();
+      await utils.registerChild(child, POSITIONS.DOWNSTREAM);
+      const after = Date.now();
+
+      const entry = utils.registeredChildren.get('child-1');
+      expect(entry.softwareType).toBe('machine');
+      expect(entry.position).toBe(POSITIONS.DOWNSTREAM);
+      expect(entry.registeredAt).toBeGreaterThanOrEqual(before);
+      expect(entry.registeredAt).toBeLessThanOrEqual(after);
+    });
+
+    it('should store the child in mainClass.child[softwareType][category]', async () => {
+      const child = createMockChild({ softwareType: 'measurement', category: 'sensor' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(parent.child.measurement).toBeDefined();
+      expect(parent.child.measurement.sensor).toBeInstanceOf(Array);
+      expect(parent.child.measurement.sensor).toContain(child);
+    });
+
+    it('should set the parent reference on the child', async () => {
+      const child = createMockChild();
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(child.parent).toEqual([parent]);
+    });
+
+    it('should set positionVsParent on the child', async () => {
+      const child = createMockChild();
+      await utils.registerChild(child, POSITIONS.DOWNSTREAM);
+
+      expect(child.positionVsParent).toBe(POSITIONS.DOWNSTREAM);
+    });
+
+    it('should lowercase the softwareType before storing', async () => {
+      const child = createMockChild({ softwareType: 'Measurement' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      const entry = utils.registeredChildren.get('child-1');
+      expect(entry.softwareType).toBe('measurement');
+      expect(parent.child.measurement).toBeDefined();
+    });
+
+    it('should delegate to mainClass.registerChild when it is a function', async () => {
+      const registerSpy = jest.fn();
+      parent.registerChild = registerSpy;
+      const child = createMockChild({ softwareType: 'measurement' });
+
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(registerSpy).toHaveBeenCalledWith(child, 'measurement');
+    });
+
+    it('should NOT throw when mainClass has no registerChild method', async () => {
+      delete parent.registerChild;
+      const child = createMockChild();
+
+      await expect(utils.registerChild(child, POSITIONS.UPSTREAM)).resolves.not.toThrow();
+    });
+
+    it('should log a debug message on registration', async () => {
+      const child = createMockChild({ name: 'Pump1', id: 'p1' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(parent.logger.debug).toHaveBeenCalledWith(
+        expect.stringContaining('Registering child: Pump1')
+      );
+    });
+
+    it('should handle empty softwareType gracefully', async () => {
+      const child = createMockChild({ softwareType: '' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      const entry = utils.registeredChildren.get('child-1');
+      expect(entry.softwareType).toBe('');
+    });
+  });
+
+  // ── Multiple children ────────────────────────────────────────────────────
+  describe('multiple children registration', () => {
+    it('should register multiple children of the same softwareType', async () => {
+      const c1 = createMockChild({ id: 'c1', name: 'Sensor1', softwareType: 'measurement' });
+      const c2 = createMockChild({ id: 'c2', name: 'Sensor2', softwareType: 'measurement' });
+
+      await utils.registerChild(c1, POSITIONS.UPSTREAM);
+      await utils.registerChild(c2, POSITIONS.DOWNSTREAM);
+
+      expect(utils.registeredChildren.size).toBe(2);
+      expect(parent.child.measurement.sensor).toHaveLength(2);
+    });
+
+    it('should register children of different softwareTypes', async () => {
+      const sensor = createMockChild({ id: 's1', softwareType: 'measurement' });
+      const machine = createMockChild({ id: 'm1', softwareType: 'machine', category: 'pump' });
+
+      await utils.registerChild(sensor, POSITIONS.UPSTREAM);
+      await utils.registerChild(machine, POSITIONS.AT_EQUIPMENT);
+
+      expect(parent.child.measurement).toBeDefined();
+      expect(parent.child.machine).toBeDefined();
+      expect(parent.child.machine.pump).toContain(machine);
+    });
+
+    it('should register children of different categories under the same softwareType', async () => {
+      const sensor = createMockChild({ id: 's1', softwareType: 'measurement', category: 'sensor' });
+      const analyser = createMockChild({ id: 'a1', softwareType: 'measurement', category: 'analyser' });
+
+      await utils.registerChild(sensor, POSITIONS.UPSTREAM);
+      await utils.registerChild(analyser, POSITIONS.DOWNSTREAM);
+
+      expect(parent.child.measurement.sensor).toHaveLength(1);
+      expect(parent.child.measurement.analyser).toHaveLength(1);
+    });
+
+    it('should support multiple parents on a child (array append)', async () => {
+      const parent2 = createMockParent();
+      const utils2 = new ChildRegistrationUtils(parent2);
+      const child = createMockChild();
+
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+      await utils2.registerChild(child, POSITIONS.DOWNSTREAM);
+
+      expect(child.parent).toEqual([parent, parent2]);
+    });
+  });
+
+  // ── Duplicate registration ───────────────────────────────────────────────
+  describe('duplicate registration', () => {
+    it('should overwrite the registry entry when the same child id is registered twice', async () => {
+      const child = createMockChild({ id: 'dup-1' });
+
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+      await utils.registerChild(child, POSITIONS.DOWNSTREAM);
+
+      // Map.set overwrites, so still size 1
+      expect(utils.registeredChildren.size).toBe(1);
+      const entry = utils.registeredChildren.get('dup-1');
+      expect(entry.position).toBe(POSITIONS.DOWNSTREAM);
+    });
+
+    it('should push the child into the category array again on duplicate registration', async () => {
+      const child = createMockChild({ id: 'dup-1' });
+
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      // _storeChild does a push each time
+      expect(parent.child.measurement.sensor).toHaveLength(2);
+    });
+  });
+
+  // ── Measurement context setup ────────────────────────────────────────────
+  describe('measurement context on child', () => {
+    it('should call setChildId, setChildName, setParentRef when child has measurements', async () => {
+      const measurements = {
+        setChildId: jest.fn(),
+        setChildName: jest.fn(),
+        setParentRef: jest.fn(),
+      };
+      const child = createMockChild({ id: 'mc-1', name: 'Sensor1', measurements });
+
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(measurements.setChildId).toHaveBeenCalledWith('mc-1');
+      expect(measurements.setChildName).toHaveBeenCalledWith('Sensor1');
+      expect(measurements.setParentRef).toHaveBeenCalledWith(parent);
+    });
+
+    it('should skip measurement setup when child has no measurements object', async () => {
+      const child = createMockChild({ measurements: null });
+
+      // Should not throw
+      await expect(utils.registerChild(child, POSITIONS.UPSTREAM)).resolves.not.toThrow();
+    });
+  });
+
+  // ── getChildrenOfType ────────────────────────────────────────────────────
+  describe('getChildrenOfType()', () => {
+    beforeEach(async () => {
+      const s1 = createMockChild({ id: 's1', softwareType: 'measurement', category: 'sensor' });
+      const s2 = createMockChild({ id: 's2', softwareType: 'measurement', category: 'sensor' });
+      const a1 = createMockChild({ id: 'a1', softwareType: 'measurement', category: 'analyser' });
+      const m1 = createMockChild({ id: 'm1', softwareType: 'machine', category: 'pump' });
+
+      await utils.registerChild(s1, POSITIONS.UPSTREAM);
+      await utils.registerChild(s2, POSITIONS.DOWNSTREAM);
+      await utils.registerChild(a1, POSITIONS.UPSTREAM);
+      await utils.registerChild(m1, POSITIONS.AT_EQUIPMENT);
+    });
+
+    it('should return all children of a given softwareType', () => {
+      const measurements = utils.getChildrenOfType('measurement');
+      expect(measurements).toHaveLength(3);
+    });
+
+    it('should return children filtered by category', () => {
+      const sensors = utils.getChildrenOfType('measurement', 'sensor');
+      expect(sensors).toHaveLength(2);
+    });
+
+    it('should return empty array for unknown softwareType', () => {
+      expect(utils.getChildrenOfType('nonexistent')).toEqual([]);
+    });
+
+    it('should return empty array for unknown category', () => {
+      expect(utils.getChildrenOfType('measurement', 'nonexistent')).toEqual([]);
+    });
+  });
+
+  // ── getChildById ─────────────────────────────────────────────────────────
+  describe('getChildById()', () => {
+    it('should return the child by its id', async () => {
+      const child = createMockChild({ id: 'find-me' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(utils.getChildById('find-me')).toBe(child);
+    });
+
+    it('should return null for unknown id', () => {
+      expect(utils.getChildById('does-not-exist')).toBeNull();
+    });
+  });
+
+  // ── getAllChildren ───────────────────────────────────────────────────────
+  describe('getAllChildren()', () => {
+    it('should return an empty array when no children registered', () => {
+      expect(utils.getAllChildren()).toEqual([]);
+    });
+
+    it('should return all registered child objects', async () => {
+      const c1 = createMockChild({ id: 'c1' });
+      const c2 = createMockChild({ id: 'c2' });
+      await utils.registerChild(c1, POSITIONS.UPSTREAM);
+      await utils.registerChild(c2, POSITIONS.DOWNSTREAM);
+
+      const all = utils.getAllChildren();
+      expect(all).toHaveLength(2);
+      expect(all).toContain(c1);
+      expect(all).toContain(c2);
+    });
+  });
+
+  // ── logChildStructure ───────────────────────────────────────────────────
+  describe('logChildStructure()', () => {
+    it('should log the child structure via debug', async () => {
+      const child = createMockChild({ id: 'log-1', name: 'LogChild' });
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      utils.logChildStructure();
+
+      expect(parent.logger.debug).toHaveBeenCalledWith(
+        'Current child structure:',
+        expect.any(String)
+      );
+    });
+  });
+
+  // ── _storeChild (internal) ──────────────────────────────────────────────
+  describe('_storeChild() internal behaviour', () => {
+    it('should create the child object on parent if it does not exist', async () => {
+      delete parent.child;
+      const child = createMockChild();
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(parent.child).toBeDefined();
+      expect(parent.child.measurement.sensor).toContain(child);
+    });
+
+    it('should use "sensor" as default category when asset.category is absent', async () => {
+      const child = createMockChild();
+      // remove asset.category to trigger default
+      delete child.config.asset.category;
+      await utils.registerChild(child, POSITIONS.UPSTREAM);
+
+      expect(parent.child.measurement.sensor).toContain(child);
+    });
+  });
+});