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Tooling · hard

44. Unit Testing with Mocks & Stubs

Testing pure logic and isolating async boundaries.

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Unit tests isolate units of code. Asynchronous network requests and provider RPC calls should be mocked to ensure deterministic, fast test runs.

js
test("formats wei to ether correctly", () => {
  expect(formatEther(1000000000000000000n)).toBe("1.0");
});

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Check your understanding

  1. 1. Why mock RPC node calls in unit tests?

  2. 2. What is an assertion in a test?

  3. 3. What happens if an async test fails to await a promise?

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