chore: add coverage reporting, Codecov badge, and improvement suggestions

.github/workflows/coverage.yml

@@ -0,0 +1,70 @@
+name: coverage
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+jobs:
+  coverage-linux:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Install dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y $(cat .github/workflows/apt-deps.txt) gcovr
+    - name: Install latest SDL
+      run: |
+        wget https://www.libsdl.org/release/SDL2-2.24.1.tar.gz
+        tar -xzf SDL2-2.24.1.tar.gz
+        cd SDL2-2.24.1
+        ./configure
+        make -j $(nproc)
+        sudo make install
+    - name: Install latest tinyxml2
+      run: |
+        wget https://github.com/leethomason/tinyxml2/archive/refs/tags/10.0.0.tar.gz
+        tar -xzf 10.0.0.tar.gz
+        cd tinyxml2-10.0.0
+        mkdir build
+        cd build
+        cmake ..
+        make
+        sudo make install
+    - name: Install Python dependencies
+      run: python3 -m pip install -r requirements.txt
+    - name: Configure with coverage instrumentation
+      run: |
+        cmake --no-warn-unused-cli -H. -Bbuild-coverage -GNinja \
+          -DCMAKE_BUILD_TYPE=Debug \
+          -DLUS_BUILD_TESTS=ON \
+          -DCMAKE_CXX_FLAGS="--coverage" \
+          -DCMAKE_C_FLAGS="--coverage" \
+          -DCMAKE_EXE_LINKER_FLAGS="--coverage"
+      env:
+        CC: gcc-12
+        CXX: g++-12
+    - name: Build
+      run: cmake --build build-coverage --config Debug --parallel $(nproc)
+    - name: Run tests
+      run: ctest --test-dir build-coverage --output-on-failure
+      env:
+        SDL_VIDEODRIVER: dummy
+        SDL_AUDIODRIVER: dummy
+    - name: Generate coverage report
+      run: |
+        gcovr \
+          --root . \
+          --filter 'src/' \
+          --xml-pretty \
+          --output coverage.xml \
+          build-coverage
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v5
+      with:
+        files: coverage.xml
+        fail_ci_if_error: false
+        token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -1,4 +1,6 @@
 # libultraship
+[![codecov](https://codecov.io/gh/Kenix3/libultraship/graph/badge.svg)](https://codecov.io/gh/Kenix3/libultraship)
+
 libultraship (LUS) is a library meant to provide reimplementations of libultra (n64 sdk) functions that run on modern hardware.
 
 LUS uses an asset loading system where data is stored separately from the executable in an archive file ending in `.otr` or `.o2r`. `.otr` files are [`.mpq`](http://www.zezula.net/en/mpq/main.html) compatible files. `.o2r` files are `.zip` compatible files. This separation of data from executable follows modern design practices which are more mod friendly. All one needs to do is supply a patch `.otr` or `.o2r` and the system will automatically replace the data.

codecov.yml

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+coverage:
+  status:
+    project:
+      default:
+        target: auto
+        threshold: 1%
+    patch:
+      default:
+        target: auto
+        threshold: 1%
+
+ignore:
+  - "tests/**"
+  - "build*/**"
+  - "cmake/**"
+  - "tools/**"