tests: Implement MockLLMProvider for tier 2 integration tests

packages/llm/src/index.ts

@@ -1,3 +1,4 @@
 export * from "./llm.js";
 export * from "./config.js";
 export * from "./providers/google-genai.js";
+export * from "./providers/mock.js";

packages/llm/src/providers/mock.ts

@@ -0,0 +1,24 @@
+import { z } from "zod";
+import { ILLMProvider, LLMRequest, LLMResponse } from "../llm.js";
+
+export class MockLLMProvider implements ILLMProvider {
+  providerName = "mock";
+  private callCount = 0;
+
+  constructor(private responses: unknown[]) {}
+
+  async generateStructuredResponse<T extends z.ZodTypeAny>(
+    request: LLMRequest<T>,
+  ): Promise<LLMResponse<z.infer<T>>> {
+    const next = this.responses[this.callCount++];
+    if (next === undefined) {
+      return { success: false, error: "Mock responses exhausted" };
+    }
+    try {
+      const parsed = request.schema.parse(next);
+      return { success: true, data: parsed };
+    } catch (e) {
+      return { success: false, error: e instanceof Error ? e.message : String(e) };
+    }
+  }
+}

packages/llm/tests/mock.test.ts

@@ -0,0 +1,63 @@
+import { describe, test, expect } from "vitest";
+import { z } from "zod";
+import { MockLLMProvider } from "../src/providers/mock.js";
+
+describe("MockLLMProvider Unit Tests (Tier 1)", () => {
+  test("returns parsed matching data for valid mock response", async () => {
+    const TestSchema = z.object({
+      name: z.string(),
+      age: z.number(),
+    });
+
+    const mockData = { name: "Alice", age: 30 };
+    const provider = new MockLLMProvider([mockData]);
+
+    const response = await provider.generateStructuredResponse({
+      systemPrompt: "system prompt",
+      userContext: "user context",
+      schema: TestSchema,
+    });
+
+    expect(response.success).toBe(true);
+    expect(response.data).toEqual(mockData);
+  });
+
+  test("returns failure for malformed mock response", async () => {
+    const TestSchema = z.object({
+      name: z.string(),
+      age: z.number(),
+    });
+
+    // age is a string instead of a number, which violates schema
+    const malformedData = { name: "Alice", age: "thirty" };
+    const provider = new MockLLMProvider([malformedData]);
+
+    const response = await provider.generateStructuredResponse({
+      systemPrompt: "system prompt",
+      userContext: "user context",
+      schema: TestSchema,
+    });
+
+    expect(response.success).toBe(false);
+    expect(response.error).toBeDefined();
+    expect(response.data).toBeUndefined();
+  });
+
+  test("returns failure when mock responses are exhausted", async () => {
+    const TestSchema = z.object({
+      name: z.string(),
+    });
+
+    const provider = new MockLLMProvider([]);
+
+    const response = await provider.generateStructuredResponse({
+      systemPrompt: "system prompt",
+      userContext: "user context",
+      schema: TestSchema,
+    });
+
+    expect(response.success).toBe(false);
+    expect(response.error).toBe("Mock responses exhausted");
+    expect(response.data).toBeUndefined();
+  });
+});