# Coverage

## Coverage Measurement

Wallet-core is a stable project, we value stability and safety over new features.

Test coverage is one important facet of assuring code quality, and we are strict about high test coverage.

### Checking Coverage Summary in CI build

The `Linux CI` and `Linux CI Rust` CI builds (executed on PRs and commits) contain coverage measurement, and summary is available in the build output:

```
Summary coverage rate:
  lines......: 94.5% (14576 of 15426 lines)
  functions..: 95.0% (2688 of 2830 functions)
```

### Detailed Coverage Report

Detailed coverage report can be generated locally. It includes file and line-level info on coverage.

Steps:

* Run `tools/generate-files` to make sure new added files are generated
* Run `cmake` with `-DTW_CODE_COVERAGE=ON` to enable coverage measurement

```shell
cmake -H. -Bbuild -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DTW_CODE_COVERAGE=ON
```

* Build tests

```shell
make -Cbuild -j12 tests TrezorCryptoTests
```

* Cleanup any old coverage files, and run unit tests

```shell
find . -name "*.gcda" -exec rm {} \;
./build/trezor-crypto/crypto/tests/TrezorCryptoTests
./build/tests/tests tests --gtest_output=xml
```

* Generate coverage info (slow). With the `html` argument the script will generate HTML report as well:

```shell
./tools/coverage html
```

if you see genhtml (from lcov) error on macOS like below:

```shell
c++filt: Unknown command line argument '--no-strip-underscores'.  Try: '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++filt --help'
c++filt: Did you mean '--no-strip-underscore'?
genhtml: ERROR: c++filt output not as expected (0 vs 11) lines
```

please upgrade `lcov` to min. `1.16`, or patch `genhtml` (for example /usr/local/Cellar/lcov/1.15/libexec/bin/), change `--no-strip-underscores` to `--no-strip-underscore`

Open the generated `coverage/index.html` to view the report.

See also [tools/coverage](https://github.com/trustwallet/wallet-core/blob/master/tools/coverage) and [linux-ci.yml](https://github.com/trustwallet/wallet-core/blob/master/.github/workflows/linux-ci.yml)

## Detailed Rust Coverage Report

Detailed Rust coverage report can be generated locally. It includes file and line-level info on coverage.

Steps:

* Switch to the nightly toolchain and install dev dependencies

```shell
tools/install-rust-dependencies dev
```

* Run Rust tests and generate coverage info (slow). With the `html` argument the script will generate HTML report as well:

```shell
./tools/rust-coverage html
```