Add nonblocking/asyn I/O operations

backend/tests/Clustering.service.test.js

@@ -1,18 +1,18 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest';
 
-const { createMock, mockEmbeddings } = vi.hoisted(() => {
+const { streamMock, mockEmbeddings } = vi.hoisted(() => {
   const embeddings = new Map([
     ['note_001', [1.0, 0.0, 0.0]],
     ['note_002', [0.0, 1.0, 0.0]],
   ]);
-  return { createMock: vi.fn(), mockEmbeddings: embeddings };
+  return { streamMock: vi.fn(), mockEmbeddings: embeddings };
 });
 
 vi.mock('@anthropic-ai/sdk', () => {
   return {
     default: class MockAnthropic {
       constructor() {
-        this.messages = { create: createMock };
+        this.messages = { stream: streamMock };
       }
     },
   };
@@ -34,6 +34,40 @@ const MOCK_CLUSTERS = [
   { label: 'Export Issues', noteIds: ['note_002'] },
 ];
 
+// Splits text into several text_delta events so the service is exercised
+// against a genuinely incremental stream rather than one whole payload.
+const textEvents = (text, pieces = 4) => {
+  const size = Math.max(1, Math.ceil(text.length / pieces));
+  const events = [];
+  for (let i = 0; i < text.length; i += size) {
+    events.push({
+      type: 'content_block_delta',
+      delta: { type: 'text_delta', text: text.slice(i, i + size) },
+    });
+  }
+  return events;
+};
+
+const mockStreamOf = (text) => {
+  const events = [
+    { type: 'message_start' },
+    ...textEvents(text),
+    { type: 'message_stop' },
+  ];
+  streamMock.mockImplementation(() => ({
+    async *[Symbol.asyncIterator]() {
+      for (const event of events) yield event;
+    },
+  }));
+};
+
+const mockStreamThrowing = (err) => {
+  streamMock.mockImplementation(() => ({
+    async *[Symbol.asyncIterator]() {
+      throw err;
+    },
+  }));
+};
 
 describe('clusterNotes service', () => {
 
@@ -41,27 +75,32 @@ describe('clusterNotes service', () => {
     vi.clearAllMocks();
   });
 
-  it('should call Anthropic messages.create with the correct model', async () => {
-    createMock.mockResolvedValue({
-      content: [{ type: 'text', text: JSON.stringify(MOCK_CLUSTERS) }],
-    });
+  it('should call Anthropic messages.stream with the correct model', async () => {
+    mockStreamOf(JSON.stringify(MOCK_CLUSTERS));
 
     await clusterNotes(MOCK_NOTES);
 
-    expect(createMock).toHaveBeenCalledOnce();
-    const callArgs = createMock.mock.calls[0][0];
+    expect(streamMock).toHaveBeenCalledOnce();
+    const callArgs = streamMock.mock.calls[0][0];
     expect(callArgs.model).toBe('claude-sonnet-4-20250514');
     expect(callArgs.max_tokens).toBe(4096);
   });
 
+  it('should forward an abort signal to the LLM request', async () => {
+    mockStreamOf(JSON.stringify(MOCK_CLUSTERS));
+    const controller = new AbortController();
+
+    await clusterNotes(MOCK_NOTES, { signal: controller.signal });
+
+    expect(streamMock.mock.calls[0][1]).toEqual({ signal: controller.signal });
+  });
+
   it('should include all note texts in prompt sent to the LLM API', async () => {
-    createMock.mockResolvedValue({
-      content: [{ type: 'text', text: JSON.stringify(MOCK_CLUSTERS) }],
-    });
+    mockStreamOf(JSON.stringify(MOCK_CLUSTERS));
 
     await clusterNotes(MOCK_NOTES);
 
-    const prompt = createMock.mock.calls[0][0].messages[0].content;
+    const prompt = streamMock.mock.calls[0][0].messages[0].content;
     expect(prompt).toContain('note_001');
     expect(prompt).toContain('Login is broken');
     expect(prompt).toContain('note_002');
@@ -69,9 +108,7 @@ describe('clusterNotes service', () => {
   });
 
   it('should return clusters and a cohesion score', async () => {
-    createMock.mockResolvedValue({
-      content: [{ type: 'text', text: JSON.stringify(MOCK_CLUSTERS) }],
-    });
+    mockStreamOf(JSON.stringify(MOCK_CLUSTERS));
 
     const result = await clusterNotes(MOCK_NOTES);
 
@@ -81,22 +118,35 @@ describe('clusterNotes service', () => {
     expect(result.score).toBeLessThanOrEqual(1);
   });
 
+  it('should reassemble clusters split across many stream deltas', async () => {
+    const json = JSON.stringify(MOCK_CLUSTERS);
+    streamMock.mockImplementation(() => ({
+      async *[Symbol.asyncIterator]() {
+        for (const char of json) {
+          yield { type: 'content_block_delta', delta: { type: 'text_delta', text: char } };
+        }
+      },
+    }));
+
+    const result = await clusterNotes(MOCK_NOTES);
+
+    expect(result.clusters).toEqual(MOCK_CLUSTERS);
+  });
+
   it('should throw error when the API returns non-JSON', async () => {
-    createMock.mockResolvedValue({
-      content: [{ type: 'text', text: 'An unknown error occured when generting structured response.' }],
-    });
+    mockStreamOf('An unknown error occured when generting structured response.');
 
     await expect(clusterNotes(MOCK_NOTES)).rejects.toThrow('non-JSON response');
   });
 
   it('should throw error when the API response has no text content', async () => {
-    createMock.mockResolvedValue({ content: [] });
+    mockStreamOf('');
 
     await expect(clusterNotes(MOCK_NOTES)).rejects.toThrow('no text content returned');
   });
 
   it('should throw error when Anthropic API authentication fails', async () => {
-    createMock.mockRejectedValue(new Error('401 Unauthorized'));
+    mockStreamThrowing(new Error('401 Unauthorized'));
 
     await expect(clusterNotes(MOCK_NOTES)).rejects.toThrow('401 Unauthorized');
   });
@@ -105,9 +155,7 @@ describe('clusterNotes service', () => {
     const incompleteClusters = [
       { label: 'Auth Issues', noteIds: ['note_001'] },
     ];
-    createMock.mockResolvedValue({
-      content: [{ type: 'text', text: JSON.stringify(incompleteClusters) }],
-    });
+    mockStreamOf(JSON.stringify(incompleteClusters));
 
     await expect(clusterNotes(MOCK_NOTES)).rejects.toThrow('Cluster validation failed');
   });