Testing

Running tests

# Run all tests
cargo test

# Run tests with output
cargo test -- --nocapture

# Run tests for a specific module
cargo test config::tests
cargo test stress::tests
cargo test event::tests

---

Test architecture

pitop uses a root-relative path design that makes testing straightforward. Every collector accepts a root: &Path parameter instead of hardcoding /proc/ and /sys/. In tests, a temporary directory serves as the root, populated with fixture files.

Example

#[test]
fn test_cpu_collector() {
    let tmp = tempfile::TempDir::new().unwrap();
    // Create fixture files at tmp.path().join("proc/stat")
    let collector = CpuCollector::new(tmp.path());
    // ...
}

---

Test fixtures

Fixture files live in tests/fixtures/ organized by board type:

tests/fixtures/
+-- pi5/
|   +-- device-tree-compatible
|   +-- proc/
|   +-- sys/
+-- pi4b/
|   +-- device-tree-compatible
|   +-- proc/
|   +-- sys/
+-- zero2w/
    +-- device-tree-compatible
    +-- proc/
    +-- sys/

These contain sample data from real Raspberry Pi systems, used to verify parsing logic without needing actual hardware.

---

What is tested

Unit tests

Each module includes inline #[cfg(test)] test modules:

Module	Tests
config.rs	Config loading, defaults, validation, TOML parsing, color parsing
event.rs	Key handling, tab switching, pause, theme cycling
stress.rs	Worker start/stop, add/remove, clamping, primality
ui/theme.rs	Theme lookup, custom theme building, fallback behavior
collectors/gpu.rs	vcgencmd output parsing (clock, memory, temp, codecs)
board/mod.rs	Board detection from device-tree strings
util/ring_buffer.rs	Push, capacity, ordering
util/sysfs.rs	File reading helpers
collectors/*.rs	Data parsing for each collector

Integration tests

The App struct can be instantiated with a temporary root directory for integration-level testing:

fn test_app() -> App {
    let tmp = TempDir::new().unwrap();
    App::new(BoardType::Unknown, tmp.path(), false, Config::default())
}

---

Adding tests

For a new collector

1. Add fixture data to the appropriate tests/fixtures/{board}/ directory
2. Write a test that creates the collector with a temp directory root
3. Populate the temp directory with the fixture data
4. Call collect() and assert the parsed values

For new vcgencmd parsing

1. Add a parsing function (e.g., parse_something(output: &str) -> Option<T>)
2. Write tests with sample vcgencmd output strings
3. Test valid output, malformed output, and empty input

For UI behavior

1. Create an App with test_app() helper
2. Simulate key events with handle_key()
3. Assert the resulting app state

---

Dev dependencies

Crate	Purpose
tempfile	Create temporary directories for fixture-based tests