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Zespan adds zero latency in production because events are batched asynchronously. In test environments, you want to ensure the SDK does not make network calls, slow down test suites, or leak API keys.

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Disable tracing in tests

Set sampleRate to 0 to drop all events before they reach the queue. No network calls are made. 
zespan.init({
  apiKey: process.env.ZESPAN_API_KEY ?? "zsp_test",
  sampleRate: 0, // drop all events
  environment: "test",
});
You can also skip zespan.init() entirely in tests — the SDK is a no-op if not initialized. Calls to wrapOpenAI() and other wrappers return the original client unchanged.

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Disable via environment variable

If ZESPAN_API_KEY is not set, the SDK does not initialize. In CI, simply omit the variable: 
# .env.test — no ZESPAN_API_KEY
OPENAI_API_KEY=sk-...
Or guard initialization in your application code: 
if (process.env.ZESPAN_API_KEY) {
  zespan.init({ apiKey: process.env.ZESPAN_API_KEY });
}

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Mock the SDK in unit tests

For unit tests that assert on span creation, mock the SDK module: 
// vitest
import { vi, describe, it, expect } from "vitest";

vi.mock("@zespan/sdk", () => ({
  zespan: {
    init: vi.fn(),
    wrapOpenAI: (client: unknown) => client, // return client unchanged
    wrapAnthropic: (client: unknown) => client,
  },
  withAgent: vi.fn(async (_opts, fn) => fn()),
  startSpan: vi.fn(async (_opts, fn) => fn({ setAttributes: vi.fn() })),
}));

describe("my agent", () => {
  it("calls the model once", async () => {
    // your test — Zespan SDK is a no-op
  });
});

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Use a test API key

If you want the SDK initialized in integration tests but do not want real traces sent to Zespan, set a dummy API key and point to a local mock server: 
zespan.init({
  apiKey: "zsp_test_dummy",
  endpoint: "http://localhost:4318", // local mock or equivalent
  environment: "test",
  sampleRate: 1.0,
});

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Flush in tests

If your test runner exits before the SDK flushes its event queue, traces may be silently dropped. Call zespan.flush() at the end of each test: 
afterEach(async () => {
  await zespan.flush();
});

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CI environment configuration

In CI (GitHub Actions, CircleCI, etc.), set environment to "ci" and sampleRate to 0: 
# .github/workflows/test.yml
env:
  ZESPAN_API_KEY: ${{ secrets.ZESPAN_API_KEY }}
  LUMIQTRACE_SAMPLE_RATE: "0"
  LUMIQTRACE_ENVIRONMENT: "ci"
The SDK reads LUMIQTRACE_SAMPLE_RATE as a number between 0.0 and 1.0. Set it to 0 to drop all events in CI without changing application code.

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Next steps