6.3.1. Coretests¶

The core library is primarily tested by the coretests test suite. It defines the test case and pass/fail criteria.

Although only a subset of the core library is certified, also tests for uncertified functions are executed.

One example test is coretests::slice::test_position. It calls .position 4 times with different arguments and asserts that the results are correct:

1#[test]
2fn test_position() {
3    let b = [1, 2, 3, 5, 5];
4    assert_eq!(b.iter().position(|&v| v == 9), None);
5    assert_eq!(b.iter().position(|&v| v == 5), Some(3));
6    assert_eq!(b.iter().position(|&v| v == 3), Some(2));
7    assert_eq!(b.iter().position(|&v| v == 0), None);
8}

This test suite is executed on all qualified targets of Ferrocene.

The results of the coretests test suite can be found in the “Library Test Suite” section of each targets test results.

6.3.2. Doc-tests¶

Doc-tests are the code snippets in doc-comments. The doc-tests for the core library are executed as well. Note that doc-tests are not used for code coverage.

6.3.3. Code coverage tests¶

In order to gather code coverage information, an additional test run of the coretests test suite on the x86_64-unknown-linux-gnu target is performed.

It is ensured that both the instrumented and not instrumented coretests run succeeds. This ensures that coverage instrumentation does not introduce any correctness issues.

Code coverage is measured only on one platform, x86_64-unknown-linux-gnu. This is sufficient because the code of the core library is largely platform independent, and code coverage is only a measure of the quality of the test suite. Correctness is still tested by running the tests on all qualified targets.

How it works:

1. rustc is instructed to instrument the binary by passing -Cinstrument-coverage.

2. The coretests test suite is executed. Due to the instrumentation, this will create .profraw files that contain the coverage information.

3. symbol-report is used to generate a symbol-report.json including all symbols in the certified subset and their spans.

4. blanket is used to generate a HTML coverage report from the .profraw files, the symbol-report.json, and the instrumented binaries.

6.3.4. Tidy test suite¶

The tidy test suite ensures conformance with syntax and semantic rules.

6.3.5. rustc lints¶

During compilation, rustc runs the borrow checker and executes a set of lints to ensure correctness, enforce consistency and prevent common errors.

6.3.6. Integration tests¶

The core library is heavily used in the other components of the Ferrocene toolchain, e.g. in rustc, the std library, rustdoc etc. The integration of the core library is tested by building and testing those components on all the supported platforms.