Merge graph/mutation: removeTask, removeDependency, updateTask, updateEdgeAttributes

2026-04-27 11:53:42 +00:00
parent 95ef4b023b 5adc712193
commit aabc9e2fb5
4 changed files with 508 additions and 10 deletions
--- a/test/mutation.test.ts
+++ b/test/mutation.test.ts
@@ -0,0 +1,328 @@
+import { describe, it, expect } from 'vitest';
+import { TaskGraph } from '../src/graph/index.js';
+import { TaskNotFoundError } from '../src/error/index.js';
+import type { TaskGraphSerialized } from '../src/schema/index.js';
+
+// ---------------------------------------------------------------------------
+// Mutation method tests (acceptance criteria from task file)
+// ---------------------------------------------------------------------------
+
+/**
+ * Helper: create a simple TaskGraph with two nodes and one edge.
+ * Graph: A → B  (edge key: "a->b")
+ */
+function createSimpleGraph(): TaskGraph {
+  const data: TaskGraphSerialized = {
+    attributes: {},
+    options: { type: 'directed', multi: false, allowSelfLoops: false },
+    nodes: [
+      { key: 'a', attributes: { name: 'Task A', risk: 'low', scope: 'narrow' } },
+      { key: 'b', attributes: { name: 'Task B', risk: 'medium', impact: 'component' } },
+    ],
+    edges: [
+      { key: 'a->b', source: 'a', target: 'b', attributes: { qualityRetention: 0.9 } },
+    ],
+  };
+  return new TaskGraph(data);
+}
+
+/**
+ * Helper: create a diamond TaskGraph.
+ * Graph: A → B, A → C, B → D, C → D
+ */
+function createDiamondGraph(): TaskGraph {
+  const data: TaskGraphSerialized = {
+    attributes: {},
+    options: { type: 'directed', multi: false, allowSelfLoops: false },
+    nodes: [
+      { key: 'a', attributes: { name: 'Task A' } },
+      { key: 'b', attributes: { name: 'Task B' } },
+      { key: 'c', attributes: { name: 'Task C' } },
+      { key: 'd', attributes: { name: 'Task D' } },
+    ],
+    edges: [
+      { key: 'a->b', source: 'a', target: 'b', attributes: { qualityRetention: 0.9 } },
+      { key: 'a->c', source: 'a', target: 'c', attributes: { qualityRetention: 0.85 } },
+      { key: 'b->d', source: 'b', target: 'd', attributes: { qualityRetention: 0.9 } },
+      { key: 'c->d', source: 'c', target: 'd', attributes: { qualityRetention: 0.8 } },
+    ],
+  };
+  return new TaskGraph(data);
+}
+
+// ---------------------------------------------------------------------------
+// removeTask
+// ---------------------------------------------------------------------------
+
+describe('removeTask', () => {
+  it('removes an existing task from the graph', () => {
+    const tg = createSimpleGraph();
+    expect(tg.raw.hasNode('a')).toBe(true);
+    tg.removeTask('a');
+    expect(tg.raw.hasNode('a')).toBe(false);
+  });
+
+  it('cascades edge removal (graphology handles this automatically)', () => {
+    const tg = createSimpleGraph();
+    expect(tg.raw.hasEdge('a->b')).toBe(true);
+    tg.removeTask('a');
+    // Edge a->b should also be gone because node 'a' was dropped
+    expect(tg.raw.hasEdge('a->b')).toBe(false);
+    expect(tg.raw.size).toBe(0);
+  });
+
+  it('is a no-op when the node does not exist', () => {
+    const tg = createSimpleGraph();
+    expect(tg.raw.order).toBe(2);
+    expect(tg.raw.size).toBe(1);
+    // Remove a nonexistent node — should not throw or change the graph
+    tg.removeTask('nonexistent');
+    expect(tg.raw.order).toBe(2);
+    expect(tg.raw.size).toBe(1);
+  });
+
+  it('removes all edges attached to the dropped node in a diamond graph', () => {
+    const tg = createDiamondGraph();
+    // Node 'a' has outgoing edges to b and c
+    expect(tg.raw.outNeighbors('a')).toContain('b');
+    expect(tg.raw.outNeighbors('a')).toContain('c');
+    tg.removeTask('a');
+    // All edges from a should be gone
+    expect(tg.raw.hasEdge('a->b')).toBe(false);
+    expect(tg.raw.hasEdge('a->c')).toBe(false);
+    // b, c, d still exist
+    expect(tg.raw.hasNode('b')).toBe(true);
+    expect(tg.raw.hasNode('c')).toBe(true);
+    expect(tg.raw.hasNode('d')).toBe(true);
+    // Edges b->d and c->d still exist
+    expect(tg.raw.hasEdge('b->d')).toBe(true);
+    expect(tg.raw.hasEdge('c->d')).toBe(true);
+  });
+});
+
+// ---------------------------------------------------------------------------
+// removeDependency
+// ---------------------------------------------------------------------------
+
+describe('removeDependency', () => {
+  it('removes an existing edge from the graph', () => {
+    const tg = createSimpleGraph();
+    expect(tg.raw.hasEdge('a->b')).toBe(true);
+    tg.removeDependency('a', 'b');
+    expect(tg.raw.hasEdge('a->b')).toBe(false);
+    expect(tg.raw.size).toBe(0);
+  });
+
+  it('uses the deterministic edge key format ${prerequisite}->${dependent}', () => {
+    const tg = createSimpleGraph();
+    // The edge key must be exactly "a->b"
+    expect(tg.raw.hasEdge('a->b')).toBe(true);
+    // After removal, the key should no longer exist
+    tg.removeDependency('a', 'b');
+    expect(tg.raw.hasEdge('a->b')).toBe(false);
+  });
+
+  it('is a no-op when the edge does not exist', () => {
+    const tg = createSimpleGraph();
+    // Remove a nonexistent edge — should not throw or change the graph
+    tg.removeDependency('b', 'a'); // reverse direction doesn't exist
+    expect(tg.raw.order).toBe(2);
+    expect(tg.raw.size).toBe(1);
+  });
+
+  it('is a no-op when neither node exists', () => {
+    const tg = createSimpleGraph();
+    tg.removeDependency('x', 'y');
+    expect(tg.raw.order).toBe(2);
+    expect(tg.raw.size).toBe(1);
+  });
+
+  it('removes only the specified edge in a multi-edge graph', () => {
+    const tg = createDiamondGraph();
+    expect(tg.raw.size).toBe(4);
+    tg.removeDependency('a', 'b');
+    expect(tg.raw.hasEdge('a->b')).toBe(false);
+    // Other edges still exist
+    expect(tg.raw.hasEdge('a->c')).toBe(true);
+    expect(tg.raw.hasEdge('b->d')).toBe(true);
+    expect(tg.raw.hasEdge('c->d')).toBe(true);
+    expect(tg.raw.size).toBe(3);
+  });
+
+  it('preserves nodes after edge removal', () => {
+    const tg = createSimpleGraph();
+    tg.removeDependency('a', 'b');
+    // Both nodes should still exist
+    expect(tg.raw.hasNode('a')).toBe(true);
+    expect(tg.raw.hasNode('b')).toBe(true);
+  });
+});
+
+// ---------------------------------------------------------------------------
+// updateTask
+// ---------------------------------------------------------------------------
+
+describe('updateTask', () => {
+  it('merges partial attributes into an existing node', () => {
+    const tg = createSimpleGraph();
+    // Node 'a' starts with { name: 'Task A', risk: 'low', scope: 'narrow' }
+    tg.updateTask('a', { risk: 'high' });
+    const attrs = tg.raw.getNodeAttributes('a');
+    expect(attrs.name).toBe('Task A'); // unchanged
+    expect(attrs.risk).toBe('high'); // updated
+    expect(attrs.scope).toBe('narrow'); // unchanged
+  });
+
+  it('merges multiple attributes at once', () => {
+    const tg = createSimpleGraph();
+    tg.updateTask('a', { risk: 'critical', status: 'blocked' });
+    const attrs = tg.raw.getNodeAttributes('a');
+    expect(attrs.name).toBe('Task A'); // unchanged
+    expect(attrs.risk).toBe('critical'); // updated
+    expect(attrs.scope).toBe('narrow'); // unchanged
+    expect(attrs.status).toBe('blocked'); // newly set
+  });
+
+  it('throws TaskNotFoundError if the task does not exist', () => {
+    const tg = createSimpleGraph();
+    expect(() => {
+      tg.updateTask('nonexistent', { risk: 'high' });
+    }).toThrow(TaskNotFoundError);
+  });
+
+  it('TaskNotFoundError has the correct taskId property', () => {
+    const tg = createSimpleGraph();
+    try {
+      tg.updateTask('nonexistent', { risk: 'high' });
+      expect.unreachable('Should have thrown');
+    } catch (e) {
+      expect(e).toBeInstanceOf(TaskNotFoundError);
+      const err = e as TaskNotFoundError;
+      expect(err.taskId).toBe('nonexistent');
+    }
+  });
+
+  it('shallow merge — new fields can be added', () => {
+    const tg = createSimpleGraph();
+    // Node 'b' starts with { name: 'Task B', risk: 'medium', impact: 'component' }
+    tg.updateTask('b', { scope: 'broad', level: 'implementation' });
+    const attrs = tg.raw.getNodeAttributes('b');
+    expect(attrs.name).toBe('Task B');
+    expect(attrs.risk).toBe('medium');
+    expect(attrs.impact).toBe('component');
+    expect(attrs.scope).toBe('broad');
+    expect(attrs.level).toBe('implementation');
+  });
+
+  it('can update the name field', () => {
+    const tg = createSimpleGraph();
+    tg.updateTask('a', { name: 'Updated Task A' });
+    const attrs = tg.raw.getNodeAttributes('a');
+    expect(attrs.name).toBe('Updated Task A');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// updateEdgeAttributes
+// ---------------------------------------------------------------------------
+
+describe('updateEdgeAttributes', () => {
+  it('merges partial attributes into an existing edge', () => {
+    const tg = createSimpleGraph();
+    // Edge 'a->b' starts with { qualityRetention: 0.9 }
+    tg.updateEdgeAttributes('a', 'b', { qualityRetention: 0.75 });
+    const attrs = tg.raw.getEdgeAttributes('a->b');
+    expect(attrs.qualityRetention).toBe(0.75);
+  });
+
+  it('uses the deterministic edge key format to identify the edge', () => {
+    const tg = createDiamondGraph();
+    // Update edge a->c (qualityRetention: 0.85)
+    tg.updateEdgeAttributes('a', 'c', { qualityRetention: 0.5 });
+    const attrs = tg.raw.getEdgeAttributes('a->c');
+    expect(attrs.qualityRetention).toBe(0.5);
+    // Other edges unchanged
+    expect(tg.raw.getEdgeAttributes('a->b').qualityRetention).toBe(0.9);
+    expect(tg.raw.getEdgeAttributes('b->d').qualityRetention).toBe(0.9);
+    expect(tg.raw.getEdgeAttributes('c->d').qualityRetention).toBe(0.8);
+  });
+
+  it('throws TaskNotFoundError if the edge does not exist', () => {
+    const tg = createSimpleGraph();
+    expect(() => {
+      tg.updateEdgeAttributes('b', 'a', { qualityRetention: 0.5 }); // reverse edge doesn't exist
+    }).toThrow(TaskNotFoundError);
+  });
+
+  it('throws TaskNotFoundError when neither node exists', () => {
+    const tg = createSimpleGraph();
+    expect(() => {
+      tg.updateEdgeAttributes('x', 'y', { qualityRetention: 0.5 });
+    }).toThrow(TaskNotFoundError);
+  });
+
+  it('TaskNotFoundError for missing edge has the edge key as taskId', () => {
+    const tg = createSimpleGraph();
+    try {
+      tg.updateEdgeAttributes('x', 'y', { qualityRetention: 0.5 });
+      expect.unreachable('Should have thrown');
+    } catch (e) {
+      expect(e).toBeInstanceOf(TaskNotFoundError);
+      const err = e as TaskNotFoundError;
+      expect(err.taskId).toBe('x->y');
+    }
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Standalone function tests (via re-exports from module)
+// ---------------------------------------------------------------------------
+
+describe('standalone mutation functions', () => {
+  it('removeTask is exported from the module', async () => {
+    const mod = await import('../src/graph/mutation.js');
+    expect(typeof mod.removeTask).toBe('function');
+  });
+
+  it('removeDependency is exported from the module', async () => {
+    const mod = await import('../src/graph/mutation.js');
+    expect(typeof mod.removeDependency).toBe('function');
+  });
+
+  it('updateTask is exported from the module', async () => {
+    const mod = await import('../src/graph/mutation.js');
+    expect(typeof mod.updateTask).toBe('function');
+  });
+
+  it('updateEdgeAttributes is exported from the module', async () => {
+    const mod = await import('../src/graph/mutation.js');
+    expect(typeof mod.updateEdgeAttributes).toBe('function');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Integration: mutations maintain deterministic edge key format
+// ---------------------------------------------------------------------------
+
+describe('mutation edge key format invariants', () => {
+  it('removeDependency uses the deterministic key to find the edge', () => {
+    const tg = createDiamondGraph();
+    // Remove by (prerequisite, dependent) pair — internally uses "a->c" key
+    tg.removeDependency('a', 'c');
+    expect(tg.raw.hasEdge('a->c')).toBe(false);
+    // Verify the edge key is gone from the graph's edge list
+    const remainingEdges = [...tg.raw.edges()];
+    expect(remainingEdges).not.toContain('a->c');
+    expect(remainingEdges).toContain('a->b');
+  });
+
+  it('updateEdgeAttributes uses the deterministic key to find the edge', () => {
+    const tg = createDiamondGraph();
+    tg.updateEdgeAttributes('b', 'd', { qualityRetention: 0.5 });
+    // Only the edge "b->d" is affected
+    expect(tg.raw.getEdgeAttributes('b->d').qualityRetention).toBe(0.5);
+    expect(tg.raw.getEdgeAttributes('a->b').qualityRetention).toBe(0.9);
+    expect(tg.raw.getEdgeAttributes('a->c').qualityRetention).toBe(0.85);
+    expect(tg.raw.getEdgeAttributes('c->d').qualityRetention).toBe(0.8);
+  });
+});