ai-agent-skills / android

---
description: Unit testing best practices with BDD style
alwaysApply: false
---
- Name test functions in BDD style: given_<condition>_when_<action>_then_<result>
- Use GIVEN, WHEN, THEN comments in the test body for clarity.
- Write one behavioral scenario per test.
- Use mocks (MockK, Mockito) to isolate dependencies.
- Prefer runTest or coroutine test rules for suspend functions.
- Avoid fragile tests with real-time delays or random input.
- Example:
```kotlin
@Test
fun givenValidUser_whenFetchUser_thenReturnsUser() {
    // GIVEN
    val userId = 123
    coEvery { userRepo.getUser(userId) } returns User(userId, "Alice")

    // WHEN
    val result = runBlocking { sut.fetchUser(userId) }

    // THEN
    assertEquals("Alice", result.name)
}