Add valid palindrome in Python with unit tests

.github/PRE_COMMIT_HOOK.md

@@ -0,0 +1,110 @@
+# Pre-commit Hook Configuration
+
+This repository uses a pre-commit hook to ensure code quality and prevent broken commits.
+
+## What the pre-commit hook does
+
+The pre-commit hook automatically runs the following checks before allowing any commit:
+
+1. **Code Formatting** (`make format`)
+
+   - Formats C++ files using `clang-format`
+   - Formats Python files using `ruff` (or `black` as fallback)
+   - Automatically stages formatted files if changes are made
+
+2. **Code Linting** (`make lint`)
+
+   - Lints C++ files using `clang-tidy`
+   - Lints Python files using `ruff` (or `flake8` as fallback)
+
+3. **Tests** (`make test:all`)
+   - Runs all C++ tests using Google Test
+   - Runs all Python tests using pytest
+
+## Installation
+
+The pre-commit hook is already installed in this repository. If you're setting up a new clone, the hook should work automatically.
+
+## Manual Testing
+
+You can manually test the pre-commit hook by running:
+
+```bash
+./.git/hooks/pre-commit
+```
+
+## Bypassing the hook (not recommended)
+
+If you absolutely need to bypass the pre-commit hook (e.g., for a work-in-progress commit), you can use:
+
+```bash
+git commit --no-verify -m "your commit message"
+```
+
+**Warning:** This is not recommended as it can introduce broken code into the repository.
+
+## Troubleshooting
+
+### Hook fails on formatting
+
+- The hook automatically fixes formatting issues and stages the corrected files
+- If formatting fails, check that you have the required tools installed:
+  - C++: `clang-format`
+  - Python: `ruff` or `black`
+
+### Hook fails on linting
+
+- Fix the linting issues reported by running `make lint` to see details
+- Common issues include:
+  - Unused variables
+  - Code style violations
+  - Missing includes
+
+### Hook fails on tests
+
+- Fix the failing tests by running `make test:all` to see details
+- Ensure all new code has corresponding tests
+- Verify that existing functionality wasn't broken
+
+### Installing required tools
+
+For macOS (using Homebrew):
+
+```bash
+# C++ tools
+brew install clang-format llvm
+
+# Python tools (if not using requirements.txt)
+pip install ruff pytest
+
+# Google Test (for C++ tests)
+brew install googletest
+```
+
+For Ubuntu/Debian:
+
+```bash
+# C++ tools
+sudo apt-get install clang-format clang-tidy
+
+# Python tools (if not using requirements.txt)
+pip install ruff pytest
+
+# Google Test (for C++ tests)
+sudo apt-get install libgtest-dev
+```
+
+## Configuration
+
+The pre-commit hook uses the existing Makefile targets. To modify the behavior:
+
+1. **Formatting rules**: Modify the `format-cpp` and `format-python` targets in `Makefile`
+2. **Linting rules**: Modify the `lint-cpp` and `lint-python` targets in `Makefile`
+3. **Test configuration**: Modify the `test:all` target in `Makefile`
+
+## Benefits
+
+- **Consistent code style**: All code follows the same formatting standards
+- **Early error detection**: Linting catches potential issues before they reach the repository
+- **Reliable codebase**: Tests ensure that new changes don't break existing functionality
+- **Team productivity**: Reduces time spent on code review for style and basic issues

.github/workflows/python-package-conda.yml

@@ -1,6 +1,9 @@
-name: Python Lint & Test
+---
+name: Presubmit (Python)
 
-on: [push]
+on: # yamllint disable-line rule:truthy
+  pull_request:
+    branches: ["main"]
 
 jobs:
   build-python:
@@ -11,6 +14,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Fetch full history for git diff
+
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
         with:
@@ -22,11 +28,105 @@ jobs:
           python -m pip install --upgrade pip
           pip install -r requirements.txt
 
+      - name: Detect changed Python files
+        id: detect-changes
+        run: |
+          # Get list of changed files
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            # For PR, compare with base branch
+            CHANGED_FILES=$(git diff --name-only \
+              ${{ github.event.pull_request.base.sha }}..HEAD)
+          else
+            # For push, compare with previous commit
+            if [ "${{ github.event.before }}" = \
+              "0000000000000000000000000000000000000000" ]; then
+              # First commit in repo
+              CHANGED_FILES=$(git diff --name-only --diff-filter=A HEAD)
+            else
+              CHANGED_FILES=$(git diff --name-only \
+                ${{ github.event.before }}..HEAD)
+            fi
+          fi
+
+          echo "All changed files:"
+          echo "$CHANGED_FILES"
+
+          # Filter for Python files only
+          CHANGED_PYTHON_FILES=$(echo "$CHANGED_FILES" | \
+            grep '\.py$' || true)
+
+          # Extract unique problem directories from changed Python files
+          CHANGED_PROBLEMS=$(echo "$CHANGED_PYTHON_FILES" | \
+            grep -E '^problems/[^/]+/' | cut -d'/' -f2 | \
+            sort -u | tr '\n' ' ' || true)
+
+          # Check if requirements.txt or Python-related config files changed
+          PYTHON_CONFIG_CHANGES=$(echo "$CHANGED_FILES" | \
+            grep -E '(requirements\.txt|setup\.py|pyproject\.toml)$' || true)
+
+          echo "Changed Python files:"
+          echo "$CHANGED_PYTHON_FILES"
+          echo "Changed problems: $CHANGED_PROBLEMS"
+          echo "Python config changes: $PYTHON_CONFIG_CHANGES"
+
+          # Set outputs
+          echo "changed_problems=$CHANGED_PROBLEMS" >> $GITHUB_OUTPUT
+          echo "has_python_changes=$([ -n "$CHANGED_PYTHON_FILES" ] && \
+            echo 'true' || echo 'false')" >> $GITHUB_OUTPUT
+          echo "has_python_config_changes=$([ -n "$PYTHON_CONFIG_CHANGES" ] && \
+            echo 'true' || echo 'false')" >> $GITHUB_OUTPUT
+          echo "should_run_all_tests=$([ -n "$PYTHON_CONFIG_CHANGES" ] && \
+            echo 'true' || echo 'false')" >> $GITHUB_OUTPUT
+
       - name: Format Python code
+        if: steps.detect-changes.outputs.has_python_changes == 'true'
         run: make format-python
 
       - name: Lint Python code
+        if: steps.detect-changes.outputs.has_python_changes == 'true'
         run: make lint-python
 
-      - name: Run Python tests
-        run: make test-py:all
+      - name: Run Python tests for changed problems
+        if: >
+          steps.detect-changes.outputs.changed_problems != '' &&
+          steps.detect-changes.outputs.should_run_all_tests == 'false'
+        run: |
+          PROBLEMS="${{ steps.detect-changes.outputs.changed_problems }}"
+          echo "Running tests for changed problems: $PROBLEMS"
+
+          for problem in $PROBLEMS; do
+            echo "Testing problem: $problem"
+            # Convert snake_case to kebab-case for make target
+            kebab_case=$(echo "$problem" | sed 's/_/-/g')
+            make test-py:$kebab_case || exit 1
+          done
+
+      - name: Run all Python tests (dependencies changed)
+        if: steps.detect-changes.outputs.should_run_all_tests == 'true'
+        run: |
+          echo "Running all tests due to Python configuration changes"
+          make test-py:all
+
+      - name: Summary
+        if: always()
+        run: |
+          echo "## Test Summary" >> $GITHUB_STEP_SUMMARY
+
+          if [ "${{ steps.detect-changes.outputs.has_python_changes }}" = \
+            "false" ] && \
+            [ "${{ steps.detect-changes.outputs.has_python_config_changes }}" \
+            = "false" ]; then
+            echo "- No Python files changed - skipped all tasks" >> \
+            $GITHUB_STEP_SUMMARY
+          elif [ "${{ steps.detect-changes.outputs.should_run_all_tests }}" = \
+            "true" ]; then
+            echo "- Ran all tests due to config changes" >> $GITHUB_STEP_SUMMARY
+          elif [ "${{ steps.detect-changes.outputs.changed_problems }}" != \
+            "" ]; then
+            problems="${{ steps.detect-changes.outputs.changed_problems }}"
+            echo "- Ran targeted tests for: $problems" >> \
+            $GITHUB_STEP_SUMMARY
+          else
+            echo "- No tests needed (no problem files changed)" >> \
+            $GITHUB_STEP_SUMMARY
+          fi

Makefile

@@ -87,32 +87,48 @@ test\:%:
 test-cpp\:%:
 	@if [ "$*" = "all" ]; then \
 		echo "Running all C++ tests..."; \
+		overall_result=0; \
 		for dir in $(PROBLEM_DIRS); do \
 			if [ -f $$dir/*_test.cc ]; then \
 				echo "$(call color_blue,Testing C++ in $$dir...)"; \
 				$(CXX) $(CXXFLAGS) $(DEBUG_LDFLAGS) $(TEST_LDFLAGS) -I$(COMMON_DIR) -I$$dir -o $$dir/test_runner $$dir/*.cc; \
 				if [ $$? -eq 0 ]; then \
-					cd $$dir && ./test_runner --gtest_brief=1 --gtest_color=yes 2>/dev/null | tail -n +2; \
+					cd $$dir && ./test_runner --gtest_brief=1 --gtest_color=yes; \
+					test_result=$$?; \
+					if [ $$test_result -ne 0 ]; then \
+						overall_result=$$test_result; \
+					fi; \
 					rm -f $$dir/test_runner; \
+					cd - > /dev/null; \
 				else \
 					echo "$(call color_red,Failed to compile tests in $$dir)"; \
+					overall_result=1; \
 				fi; \
 				if [ "$$dir" != "$(lastword $(PROBLEM_DIRS))" ]; then \
 					echo ""; \
 				fi; \
 			fi; \
 		done; \
+		make clean SILENT=true; \
+		exit $$overall_result; \
 	else \
 		snake_case_name=$(call kebab_to_snake,$*); \
 		if [ -f $(PROBLEMS_DIR)/$$snake_case_name/$${snake_case_name}_test.cc ]; then \
 			echo "$(call color_blue,Running C++ tests for $*...)"; \
 			$(CXX) $(CXXFLAGS) $(DEBUG_LDFLAGS) $(TEST_LDFLAGS) -I$(COMMON_DIR) -I$(PROBLEMS_DIR)/$$snake_case_name -o $(PROBLEMS_DIR)/$$snake_case_name/test_runner $(PROBLEMS_DIR)/$$snake_case_name/*.cc; \
 			if [ $$? -eq 0 ]; then \
-				cd $(PROBLEMS_DIR)/$$snake_case_name && ./test_runner --gtest_color=yes 2>/dev/null | tail -n +2; \
+				cd $(PROBLEMS_DIR)/$$snake_case_name && ./test_runner --gtest_color=yes; \
+				test_result=$$?; \
 				rm -f $(PROBLEMS_DIR)/$$snake_case_name/test_runner; \
+				cd - > /dev/null; \
+				exit $$test_result; \
 			else \
 				echo "$(call color_red,Failed to compile tests for $*)"; \
+				exit 1; \
 			fi; \
+		else \
+			echo "$(call color_red,No C++ test file found for $*.)"; \
+			exit 1; \
 		fi; \
 	fi
 	@make clean SILENT=true
@@ -121,19 +137,29 @@ test-cpp\:%:
 test-py\:%:
 	@if [ "$*" = "all" ]; then \
 		echo "Running all Python tests..."; \
+		overall_result=0; \
 		for dir in $(PROBLEM_DIRS); do \
 			if [ -f $$dir/*_test.py ]; then \
-				cd $$dir && $(PYTEST) *_test.py --color=yes 2>/dev/null | tail -n +7; \
+				echo "$(call color_blue,Testing Python in $$dir...)"; \
+				cd $$dir && $(PYTEST) *_test.py --color=yes -v; \
+				test_result=$$?; \
+				if [ $$test_result -ne 0 ]; then \
+					overall_result=$$test_result; \
+				fi; \
 				cd - > /dev/null; \
+				echo ""; \
 			fi; \
 		done; \
+		make clean SILENT=true; \
+		exit $$overall_result; \
 	else \
 		snake_case_name=$(call kebab_to_snake,$*); \
 		if [ -f $(PROBLEMS_DIR)/$$snake_case_name/$${snake_case_name}_test.py ]; then \
 			echo "$(call color_blue,Running Python tests for $*...)"; \
-			cd $(PROBLEMS_DIR)/$$snake_case_name && $(PYTEST) $${snake_case_name}_test.py -v --color=yes 2>/dev/null | tail -n +8; \
+			cd $(PROBLEMS_DIR)/$$snake_case_name && $(PYTEST) $${snake_case_name}_test.py -v --color=yes; \
 		else \
 			echo "$(call color_red,No Python test file found for $*.)"; \
+			exit 1; \
 		fi; \
 	fi
 	@make clean SILENT=true
@@ -151,7 +177,7 @@ format:
 .PHONY: format-cpp
 format-cpp:
 	@echo "Formatting C++ files..."
-	@if command -v clang-format >/dev/null 2>&1; then \
+	@if command -v clang-format >/dev/null; then \
 		find $(COMMON_DIR) $(PROBLEMS_DIR) -name '*.cc' -o -name '*.h' | xargs clang-format -i; \
 		echo "$(call color_green,C++ files formatted.)"; \
 	else \
@@ -161,10 +187,10 @@ format-cpp:
 .PHONY: format-python
 format-python:
 	@echo "Formatting Python files..."
-	@if command -v ruff >/dev/null 2>&1; then \
+	@if command -v ruff >/dev/null; then \
 		ruff format $(PROBLEMS_DIR); \
 		echo "$(call color_green,Python files formatted with ruff.)"; \
-	elif command -v black >/dev/null 2>&1; then \
+	elif command -v black >/dev/null; then \
 		find $(PROBLEMS_DIR) -name '*.py' | xargs black; \
 		echo "$(call color_green,Python files formatted with black.)"; \
 	else \
@@ -180,7 +206,7 @@ lint:
 .PHONY: lint-cpp
 lint-cpp:
 	@echo "Linting C++ files..."
-	@if command -v clang-tidy >/dev/null 2>&1; then \
+	@if command -v clang-tidy >/dev/null; then \
 		find $(PROBLEMS_DIR) $(COMMON_DIR) -type f \( -name '*.cc' -o -name '*.h' \) | while read -r file; do \
 			clang-tidy "$$file" -- $(CXXFLAGS) -x c++ || true; \
 		done; \
@@ -192,10 +218,10 @@ lint-cpp:
 .PHONY: lint-python
 lint-python:
 	@echo "Linting Python files..."
-	@if command -v ruff >/dev/null 2>&1; then \
+	@if command -v ruff >/dev/null; then \
 		ruff check $(PROBLEMS_DIR); \
 		echo "$(call color_green,Python linting complete with ruff.)"; \
-	elif command -v flake8 >/dev/null 2>&1; then \
+	elif command -v flake8 >/dev/null; then \
 		find $(PROBLEMS_DIR) -name '*.py' | xargs flake8; \
 		echo "$(call color_green,Python linting complete with flake8.)"; \
 	else \