Add unit tests

.clang-tidy

@@ -0,0 +1,92 @@
+Checks: >
+ -*,
+ bugprone-*,
+ -bugprone-easily-swappable-parameters,
+ -bugprone-exception-escape,
+ cert-*,
+ -cert-err58-cpp,
+ clang-analyzer-*,
+ concurrency-*,
+ cppcoreguidelines-*,
+ -cppcoreguidelines-avoid-magic-numbers,
+ -cppcoreguidelines-avoid-const-or-ref-data-members,
+ -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
+ -cppcoreguidelines-pro-bounds-pointer-arithmetic,
+ -cppcoreguidelines-pro-type-reinterpret-cast,
+ -cppcoreguidelines-pro-type-vararg,
+ -cppcoreguidelines-owning-memory,
+ -cppcoreguidelines-avoid-do-while,
+ google-*,
+ -google-readability-todo,
+ -google-runtime-references,
+ misc-*,
+ -misc-non-private-member-variables-in-classes,
+ -misc-no-recursion,
+ modernize-*,
+ -modernize-use-trailing-return-type,
+ -modernize-avoid-c-arrays,
+ performance-*,
+ readability-*,
+ -readability-identifier-length,
+ -readability-magic-numbers,
+ -readability-function-cognitive-complexity,
+ -readability-uppercase-literal-suffix,
+ -readability-else-after-return,
+ -readability-braces-around-statements,
+ -google-readability-braces-around-statements,
+ -misc-include-cleaner
+
+WarningsAsErrors: ''
+
+CheckOptions:
+ # Naming conventions
+ - key: readability-identifier-naming.NamespaceCase
+   value: lower_case
+ - key: readability-identifier-naming.ClassCase
+   value: CamelCase
+ - key: readability-identifier-naming.StructCase
+   value: CamelCase
+ - key: readability-identifier-naming.EnumCase
+   value: CamelCase
+ - key: readability-identifier-naming.FunctionCase
+   value: camelBack
+ - key: readability-identifier-naming.VariableCase
+   value: camelBack
+ - key: readability-identifier-naming.ParameterCase
+   value: camelBack
+ - key: readability-identifier-naming.MemberCase
+   value: lower_case
+ - key: readability-identifier-naming.MemberCase.Prefix
+   value: m_
+ - key: readability-identifier-naming.ConstantMemberCase
+   value: camelBack
+ - key: readability-identifier-naming.ConstantMemberPrefix
+   value: m_
+ - key: readability-identifier-naming.ConstantCase
+   value: camelBack
+ - key: readability-identifier-naming.EnumConstantCase
+   value: UPPER_CASE
+ - key: readability-identifier-naming.GlobalConstantCase
+   value: UPPER_CASE
+ - key: readability-identifier-naming.StaticConstantCase
+   value: CamelCase
+
+ # Line length
+ - key: readability-function-size.LineThreshold
+   value: 200
+ - key: readability-function-size.StatementThreshold
+   value: 200
+
+ # Misc settings
+ - key: modernize-use-nullptr.NullMacros
+   value: 'NULL'
+ - key: performance-move-const-arg.CheckTriviallyCopyableMove
+   value: true
+ - key: cppcoreguidelines-special-member-functions.AllowSoleDefaultDtor
+   value: true
+
+# Exclude third-party code and build artifacts
+HeaderFilterRegex: '^.*/(src|test)/.*\.(h|hpp)$'
+
+# Suppress warnings from system headers
+SystemHeaders: false

.github/scripts/check-format.sh

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+#!/bin/bash
+set -euo pipefail
+
+echo "Finding changed C++ files against base branch: main"
+CHANGED_FILES=$(git diff --name-only --diff-filter=AM "origin/main...HEAD" | \
+                grep -E '\.(cpp|hpp|h)$' || true)
+
+# Filter to only files that exist (not deleted)
+EXISTING_FILES=""
+for file in $CHANGED_FILES; do
+  if [ -f "$file" ]; then
+    EXISTING_FILES="$EXISTING_FILES $file"
+  fi
+done
+
+if [ -z "$EXISTING_FILES" ]; then
+  echo "No C++ files changed, skipping format check"
+  exit 0
+fi
+
+echo "Checking formatting for: $EXISTING_FILES"
+
+# shellcheck disable=SC2086
+clang-format --dry-run --Werror $EXISTING_FILES
+
+echo "All files are properly formatted!"

.github/scripts/generate-coverage.sh

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+#!/bin/bash
+set -euo pipefail
+
+cd build
+
+echo "Running tests with coverage instrumentation..."
+export LLVM_PROFILE_FILE="caesar-%p.profraw"
+./caesar_test
+
+echo "Checking for profraw files..."
+if ! ls caesar-*.profraw 1> /dev/null 2>&1; then
+  echo "ERROR: No .profraw files found!"
+  exit 1
+fi
+
+echo "Merging profile data..."
+/usr/bin/llvm-profdata-21 merge -sparse caesar-*.profraw -o caesar.profdata
+
+echo "Generating coverage report (text summary)..."
+/usr/bin/llvm-cov-21 report ./caesar_test \
+  -instr-profile=caesar.profdata \
+  -ignore-filename-regex='test/.*' \
+  -ignore-filename-regex='.*/Catch2/.*'
+
+echo "Generating detailed HTML report..."
+/usr/bin/llvm-cov-21 show ./caesar_test \
+  -instr-profile=caesar.profdata \
+  -format=html \
+  -output-dir=coverage-report \
+  -ignore-filename-regex='test/.*' \
+  -ignore-filename-regex='.*/Catch2/.*' \
+  -show-line-counts-or-regions \
+  -show-instantiations
+
+echo "Generating per-file coverage summary..."
+echo "### Per-File Coverage Summary" > coverage-summary.txt
+/usr/bin/llvm-cov-21 report ./caesar_test \
+  -instr-profile=caesar.profdata \
+  -ignore-filename-regex='test/.*' \
+  -ignore-filename-regex='.*/Catch2/.*' \
+  >> coverage-summary.txt
+
+echo "Coverage report generated successfully"
+cat coverage-summary.txt

.github/scripts/run-clang-tidy.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+set -euo pipefail
+
+echo "Finding changed C++ files against base branch: main"
+CHANGED_FILES=$(git diff --name-only --diff-filter=AM "origin/main...HEAD" | \
+                grep -E '\.(cpp)$' | \
+                grep -v '^test/' || true)
+
+# Filter to only files that exist (not deleted)
+EXISTING_FILES=""
+for file in $CHANGED_FILES; do
+  if [ -f "$file" ]; then
+    EXISTING_FILES="$EXISTING_FILES $file"
+  fi
+done
+
+if [ -z "$EXISTING_FILES" ]; then
+  echo "No C++ files changed, skipping clang-tidy"
+  exit 0
+fi
+
+echo "Changed C++ files: $EXISTING_FILES"
+echo "Running clang-tidy..."
+
+# Run clang-tidy on changed files
+# shellcheck disable=SC2086
+clang-tidy -p build --warnings-as-errors='*' $EXISTING_FILES
+
+echo "clang-tidy completed successfully"

.github/workflows/ci.yml

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+name: CI
+
+on:
+  pull_request:
+    branches: [ main ]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+env:
+  VCPKG_ROOT: ${{ github.workspace }}/vcpkg
+  VCPKG_COMMIT: 'b1e15efef6758eaa0beb0a8732cfa66f6a68a81d'
+
+jobs:
+  build:
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y cmake ninja-build ccache
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 21 all
+          sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-21 100
+          sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-21 100
+          sudo update-alternatives --install /usr/bin/clang-scan-deps clang-scan-deps /usr/bin/clang-scan-deps-21 100
+          sudo update-alternatives --install /usr/bin/llvm-profdata llvm-profdata /usr/bin/llvm-profdata-21 100
+          sudo update-alternatives --install /usr/bin/llvm-cov llvm-cov /usr/bin/llvm-cov-21 100
+
+      - name: Setup ccache
+        uses: hendrikmuhs/ccache-action@v1.2
+        with:
+          key: ${{ runner.os }}-ccache-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-ccache-
+
+      - name: Setup vcpkg
+        uses: lukka/run-vcpkg@v11
+        with:
+          vcpkgDirectory: ${{ env.VCPKG_ROOT }}
+          vcpkgGitCommitId: ${{ env.VCPKG_COMMIT }}
+
+      - name: Configure CMake
+        run: cmake -B build --preset debug -DENABLE_COVERAGE=ON
+        env:
+          CC: /usr/bin/clang-21
+          CXX: /usr/bin/clang++-21
+          CMAKE_CXX_COMPILER_LAUNCHER: ccache
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Run tests and generate coverage
+        run: .github/scripts/generate-coverage.sh
+
+      - name: Upload coverage report
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-report
+          path: |
+            build/coverage-report/
+            build/coverage-summary.txt
+          retention-days: 30
+
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: build-artifacts
+          path: |
+            build/
+            !build/vcpkg_installed/
+          retention-days: 1
+
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    needs: build
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y cmake ninja-build
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 21 all
+          sudo update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-21 100
+          sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-21 100
+
+      - name: Download build artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: build-artifacts
+          path: build
+
+      - name: Check formatting on changed files
+        run: .github/scripts/check-format.sh
+
+      - name: Run clang-tidy on changed files
+        run: .github/scripts/run-clang-tidy.sh
+
+  coverage-comment:
+    name: Post Coverage Comment
+    runs-on: ubuntu-latest
+    needs: build
+
+    steps:
+      - name: Download coverage report
+        uses: actions/download-artifact@v4
+        with:
+          name: coverage-report
+
+      - name: Comment coverage summary on PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+            const summary = fs.readFileSync('coverage-summary.txt', 'utf8');
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: '## Code Coverage Report\n\n```\n' + summary + '\n```\n\nDetailed HTML report available in artifacts.'
+            });

.gitignore

@@ -1,2 +1,13 @@
 .cache
 build/
+vcpkg-manifest-install.log
+vcpkg_installed
+
+# Coverage
+coverage/
+*.profraw
+*.profdata
+*.gcda
+*.gcno
+*.gcov
+*.info