feat: rework just file and add code coverage generation

.github/workflows/build_and_test.yml

@@ -2,40 +2,28 @@ name: Build and test
 
 on:
   push:
-    branches: [ "main" ]
+    branches: ["main"]
   pull_request:
-    branches: [ "main" ]
+    branches: ["main"]
 
 env:
   CARGO_TERM_COLOR: always
 
 jobs:
-  build-nightly:
-
+  build:
+    strategy:
+      matrix:
+        runs-on: [ubuntu-22.04]
+        rust: [stable, nightly]
+        build-type: [debug, release]
     runs-on: ubuntu-22.04
-
-    steps:
-    - name: Rust nightly
-      run: rustup default stable
-    - uses: actions/checkout@v4
-      with:
-        lfs: true
-    - name: Install just
-      uses: extractions/setup-just@v2
-    - name: Run tests
-      run: just test
-
-  build-stable:
-
-    runs-on: ubuntu-22.04
-
     steps:
-    - name: Rust stable
-      run: rustup default stable
-    - uses: actions/checkout@v4
-      with:
-        lfs: true
-    - name: Install just
-      uses: extractions/setup-just@v2
-    - name: Run tests
-      run: just test
+      - name: Rust ${{ matrix.rust }}
+        run: rustup default ${{ matrix.rust }}
+      - uses: actions/checkout@v4
+        with:
+          lfs: true
+      - name: Install just
+        uses: extractions/setup-just@v2
+      - name: Run tests
+        run: just test ${{ matrix.build-type }}

.github/workflows/coverage.yml

@@ -0,0 +1,37 @@
+name: Code coverage
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  generate-coverage:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Rust nightly
+        run: |
+          rustup default nightly
+          rustup component add llvm-tools-preview
+      - uses: actions/checkout@v4
+        with:
+          lfs: true
+      - name: Install just
+        uses: extractions/setup-just@v2
+      - name: Install grcov
+        run: |
+          sudo apt update
+          sudo apt install -y grcov
+      - name: Install just
+        uses: extractions/setup-just@v2
+      - name: Generate coverage
+        run: just coverage
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: target/debug/coverage/byte-knight.lcov

.gitignore

@@ -2,4 +2,7 @@
 /data/lichess_db_puzzle.csv
 **/build/*
 *.exe
-**/.DS_Store
+**/.DS_Store
+*.profraw
+*.profdata
+*.lcov

Justfile

@@ -1,51 +1,103 @@
 set windows-shell := ["pwsh.exe", "-NoLogo", "-Command"]
 
-default: build
+default: (build)
 
-build:
+[group('dev')]
+[doc('Build the project (default is debug)')]
+build config="debug":
     echo "Building the project..."
-    cargo build --release --all
+    cargo build --workspace --all-features {{ if config=="release" {"--release"} else {""} }}
 
-test:
+[group('dev')]
+[doc('Build and run tests (default is debug)')]
+test config="debug":
     echo "Running tests..."
-    cargo test --release --all --all-features
+    cargo test --workspace --all-features {{ if config=="release" {"--release"} else {""} }} -- --include-ignored
 
+export LLVM_PROFILE_FILE:="./target/coverage/byte_knight-%p-%m.profraw"
+
+[group('dev')]
+[doc('Generate test coverage')]
+coverage: (build "debug")
+    echo "Running tests with coverage..."
+    mkdir -p target/coverage
+    RUSTFLAGS="-Cinstrument-coverage" \
+    cargo test --workspace -- --skip "perft"
+    grcov target/coverage engine/target/coverage chess/target/coverage -s . \
+        --binary-path ./target/debug/ --output-types lcov -o ./target/coverage/byte-knight.lcov \
+        --branch --keep-only "src/*" --keep-only "engine/*" --keep-only "chess/*" \
+        --ignore "src/bin/byte-knight/*" --ignore "chess/src/perft*"
+
+[group('dev')]
+[doc('Purge files generated by @coverage')]
+purge-coverage:
+    echo "Purging coverage data..."
+    rm -rf *.profraw
+    rm -rf target/coverage
+    rm -rf chess/target
+    rm -rf engine/target
+    rm -rf chess/*.profraw
+    rm -rf engine/*.profraw
+
+[group('dev')]
+[doc('Run clippy')]
 lint:
     cargo clippy --all --all-features --tests -- -D warnings
 
+[group('chess')]
+[group('performance')]
+[doc('Run sarch benchmark - required before committing for OpenBench.')]
 search-bench:
     echo "Running search benchmark..."
     cargo rustc --release --bin byte-knight -- -C target-cpu=native
     ./target/release/byte-knight bench
 
+[group('chess')]
+[doc('Run perft at a specified depth')]
 perft depth:
     echo "Running perft..."
     cargo run --release --bin perft -- -d {{ depth }}
 
+[group('chess')]
+[doc('Run perft over the EPD test suite')]
 perft-epd:
     echo "Running EPD perft test suite..."
     cargo run --release --bin perft -- --epd-file data/standard.epd
 
+[group('chess')]
+[group('performance')]
+[doc('Run perft benchmark over the EPD test suite')]
 perft-bench:
     echo "Running perft benchmark..."
     cargo run --release --bin perft-bench -- -e data/standard.epd
 
+[group('chess')]
+[doc('Generate magic numbers use for magic bitboards')]
 magics:
     echo "Generating magics..."
     cargo run --release --bin generate_magics
 
+[group('chess')]
+[doc('Verify that generated Zobrist hashes are unique')]
 verify-zobrist:
     echo "Verifying Zobrist hash..."
     cargo run --release --bin verify_zobrist
 
+[group('dev')]
+[doc('Generate release binaries for given target.')]
 release target:
     echo "Building release binaries..."
     cargo rustc --release --bin byte-knight --target={{ target }}
 
-cache-main: build
+[group('dev')]
+[doc('Caches the release binary to bk-main for testing.')]
+cache-main: (build "release")
     echo "Caching binary for testing..."
     cp target/release/byte-knight ./bk-main
 
-compare-to-main engine1: build
+[group('dev')]
+[group('chess')]
+[doc('Run the engine against itself. Requires @cache-main to be run first and fastchess to be installed.')]
+compare-to-main engine1: (build "release")
     echo "Comparing {{ engine1 }} to bk-main"
     fastchess -engine cmd="{{ engine1 }}" name="dev" -engine cmd="./bk-main" name="bk-main" -openings file="./data/Pohl.epd" format=epd order=random -each tc=10+0.1 -rounds 200 -repeat -concurrency 8 -sprt elo0=0 elo1=5 alpha=0.05 beta=0.1 model=normalized -output format=cutechess

README.md

@@ -1,5 +1,7 @@
 <center><h1> byte-knight </h1></center>
 
+[![codecov](https://codecov.io/gh/DeveloperPaul123/byte-knight/graph/badge.svg?token=USEPKU8K4G)](https://codecov.io/gh/DeveloperPaul123/byte-knight)
+
 `byte-knight` is a UCI compliant chess engine written in Rust. It started as a port of the chess engine I submitted for Sebatian Lague's [Chess Engine Challenge](https://github.com/DeveloperPaul123/Leonidas) where it placed in the top 32 out of 600+ entries.
 
 # Overview

engine/src/score.rs

@@ -24,6 +24,25 @@ use crate::defs::MAX_DEPTH;
 pub type ScoreType = i16;
 pub(crate) type LargeScoreType = i32;
 /// Represents a score in centipawns.
+///
+/// This type has saturating add/sub operations to prevent overflow.
+/// It will not wrap around on overflow, but instead saturate to the internal types min/max.
+///
+/// The score is represented as a signed 16-bit integer, which allows for a range of -32,768 to 32,767.
+///
+/// Example usage:
+/// ```rust
+/// use engine::score::{Score, ScoreType};
+/// let score = Score::new(150); // Represents a score of 150 centipawns
+/// let mate_score = Score::MATE; // Represents a checkmate score
+/// let draw_score = Score::DRAW; // Represents a draw score
+/// let mut s = Score::INF / 2;
+/// s += Score::INF;
+/// assert_eq!(s, Score::INF); // Saturating addition
+/// let mut ss = -Score::INF;
+/// ss -= Score::INF;
+/// assert_eq!(ss, Score::new(ScoreType::MIN)); // Saturating subtraction
+/// ```
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Default)]
 pub struct Score(pub ScoreType);
 
@@ -83,55 +102,55 @@ impl Neg for Score {
 
 impl AddAssign for Score {
     fn add_assign(&mut self, other: Score) {
-        self.0 += other.0;
+        *self = *self + other;
     }
 }
 
 impl AddAssign<ScoreType> for Score {
     fn add_assign(&mut self, other: ScoreType) {
-        self.0 += other;
+        *self = *self + other;
     }
 }
 
 impl Add for Score {
     type Output = Score;
 
-    fn add(self, other: Score) -> Score {
-        Score(self.0 + other.0)
+    fn add(self, other: Score) -> Self::Output {
+        Score(self.0.saturating_add(other.0))
     }
 }
 
 impl Add<ScoreType> for Score {
     type Output = Score;
 
-    fn add(self, other: ScoreType) -> Score {
-        Score(self.0 + other)
+    fn add(self, other: ScoreType) -> Self::Output {
+        Score(self.0.saturating_add(other))
     }
 }
 
 impl Sub for Score {
     type Output = Score;
-    fn sub(self, other: Score) -> Score {
-        Score(self.0 - other.0)
+    fn sub(self, other: Score) -> Self::Output {
+        Score(self.0.saturating_sub(other.0))
     }
 }
 
 impl Sub<ScoreType> for Score {
     type Output = Score;
     fn sub(self, other: ScoreType) -> Score {
-        Score(self.0 - other)
+        Score(self.0.saturating_sub(other))
     }
 }
 
 impl SubAssign for Score {
     fn sub_assign(&mut self, other: Score) {
-        self.0 -= other.0;
+        *self = *self - other;
     }
 }
 
 impl SubAssign<ScoreType> for Score {
     fn sub_assign(&mut self, rhs: ScoreType) {
-        self.0 -= rhs;
+        *self = *self - rhs;
     }
 }
 
@@ -193,3 +212,14 @@ impl Shl<u32> for Score {
         Score(self.0 << rhs)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn add_assign() {
+        let mut right = Score::INF / 2;
+        right += Score::INF;
+        assert_eq!(right, Score::INF);
+    }
+}

engine/src/search.rs

@@ -648,6 +648,7 @@ mod tests {
     }
 
     #[test]
+    #[ignore = "Timing on this is not consistent when instrumentation is enabled"]
     fn do_not_exceed_time() {
         let mut board = Board::default_board();
         let config = SearchParameters {