/build-gpui-apps

Test Examples

Contents: Testing Best Practices · Test Organization · Setup and Teardown · Assertions · Performance Testing · Running Tests · Basic Test Execution · Test Configuration · Advanced Test Execution · CI/CD Integration

Testing Best Practices

Test Organization

Group related tests in modules:

#[cfg(test)]
mod tests {
    use super::*;

    mod entity_tests {
        use super::*;

        #[gpui_kit::test]
        fn test_creation() { /* ... */ }

        #[gpui_kit::test]
        fn test_updates() { /* ... */ }
    }

    mod async_tests {
        use super::*;

        #[gpui_kit::test]
        async fn test_async_ops() { /* ... */ }
    }

    mod distributed_tests {
        use super::*;

        #[gpui_kit::test]
        fn test_multi_app() { /* ... */ }
    }
}

Setup and Teardown

Use helper functions for common setup:

fn create_test_counter(cx: &mut TestAppContext) -> Entity<Counter> {
    cx.new(|cx| Counter::new(cx))
}

#[gpui_kit::test]
fn test_counter_operations(cx: &mut TestAppContext) {
    let counter = create_test_counter(cx);

    // Test operations
}

Assertions

Use descriptive assertions:

#[gpui_kit::test]
fn test_counter_bounds(cx: &mut TestAppContext) {
    let counter = create_test_counter(cx);

    // Test upper bound
    for _ in 0..100 {
        counter.update(cx, |counter, cx| {
            counter.increment(cx);
        });
    }

    let count = counter.read_with(cx, |counter, _| counter.count);
    assert!(count <= 100, "Counter should not exceed maximum");

    // Test lower bound
    for _ in 0..200 {
        counter.update(cx, |counter, cx| {
            counter.decrement(cx);
        });
    }

    let count = counter.read_with(cx, |counter, _| counter.count);
    assert!(count >= 0, "Counter should not go below minimum");
}

Performance Testing

Test performance characteristics:

#[gpui_kit::test]
fn test_operation_performance(cx: &mut TestAppContext) {
    let component = cx.new(|cx| MyComponent::new(cx));

    let start = std::time::Instant::now();

    // Perform many operations
    for i in 0..1000 {
        component.update(cx, |comp, cx| {
            comp.perform_operation(i, cx);
        });
    }

    let elapsed = start.elapsed();
    assert!(elapsed < Duration::from_millis(100), "Operations should complete quickly");
}

Running Tests

Basic Test Execution

# Run all tests
cargo test

# Run specific test
cargo test test_counter_operations

# Run tests in a specific module
cargo test entity_tests::

# Run with output
cargo test -- --nocapture

Test Configuration

Enable test-support feature for GPUI tests:

[features]
test-support = ["gpui/test-support"]

cargo test --features test-support

Advanced Test Execution

# Run tests with iterations for property testing
cargo test -- --test-threads=1

# Run tests matching a pattern
cargo test test_async

# Run tests with backtrace on failure
RUST_BACKTRACE=1 cargo test

CI/CD Integration

For continuous integration:

# .github/workflows/test.yml
name: Tests
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@stable
      - name: Run tests
        run: cargo test --features test-support

GPUI's testing framework provides deterministic, fast, and comprehensive testing capabilities that mirror real application behavior while providing the control needed for thorough testing of complex UI and async scenarios.

Merged from GPUI Kit skill. Apache-2.0. Imported 2026-09-28; local links and version-sensitive guidance adapted. The current documentation and locked source take precedence over example signatures.