Write focused single-purpose tests

Break down large test cases into smaller, focused tests that each verify a single feature or behavior. Each test should have a clear purpose that is evident from its name and structure. This improves test maintainability, readability, and makes failures easier to debug.

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Break down large test cases into smaller, focused tests that each verify a single feature or behavior. Each test should have a clear purpose that is evident from its name and structure. This improves test maintainability, readability, and makes failures easier to debug.

Instead of combining multiple test cases:

#[test]
fn test_channel_behavior() {
    let (tx, rx) = channel();
    // Test multiple behaviors...
    assert!(rx.is_empty());
    tx.send(1).unwrap();
    assert!(!rx.is_empty());
    drop(tx);
    assert!(rx.is_closed());
}

Break it into focused tests:

#[test]
fn is_empty_returns_true_initially() {
    let (_, rx) = channel();
    assert!(rx.is_empty());
}

#[test]
fn is_empty_returns_false_after_send() {
    let (tx, rx) = channel();
    tx.send(1).unwrap();
    assert!(!rx.is_empty());
}

#[test]
fn is_closed_returns_true_after_sender_drop() {
    let (tx, rx) = channel();
    drop(tx);
    assert!(rx.is_closed());
}

Key benefits:

  • Clear test purpose and failure diagnosis
  • Better coverage tracking
  • Easier maintenance and updates
  • Simpler debugging when tests fail
  • More meaningful test names

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