gFlake - Google Test Deflaking Tool

A CLI tool to automatically discover and repeatedly run Google Test (gtest) test cases to identify flaky tests.

Features

• Automatic Test Discovery - Discovers all gtest test cases from your binary
• Interactive Menus - Hierarchical menus for test selection
• Multiprocess Execution - Parallel test execution for maximum throughput
• Real-time Progress - Live progress bars and statistics
• Timing Analysis - Statistical analysis of test execution times
• Failure Logging - All failed runs logged to failed_tests.log

Quick Start

1. Installation

From PyPI

Using pipx (recommended):

Install pipx if you haven't already by following the instructions.

pipx install gflake

Using pip:

If installing pipx is not an option, you may also install gflake using pip:

pip install --user gflake

Ensure that your PATH includes the directory where pip installs executables (usually ~/.local/bin on Linux/macOS).

From Source

Install Git LFS for large files by following the instructions.

Then, clone the repository and install dependencies using Poetry:

# Clone the repository
git clone git@github.com:denizariyan/gflake.git
cd gflake

# Install with Poetry
poetry install

# Alternatively, use make alias
make install

Usage

Interactive Mode (Recommended)

gflake run <path-to-your-gtest-binary>

This will:

1. Discover all tests in your binary
2. Show interactive menus to select test suites and cases
3. Execute the test repeatedly with progress bars
4. Show detailed statistics and failure analysis

Command Options

gflake run <binary> [OPTIONS]

Options:
  -t, --test-name TEXT     Full test name (e.g., 'SuiteName.TestCase') to run directly without menu
  -d, --duration FLOAT     Duration to run tests in seconds [default: 5.0]
  -p, --processes INT      Number of parallel processes [default: half of CPU cores]
  -v, --verbose            Enable verbose output
  --help                   Show help message

Examples

# Interactive mode - shows menus for test selection
gflake run <path-to-your-gtest-binary> --duration 30

# Direct test execution - runs specific test without menu
gflake run <path-to-your-gtest-binary> --test-name "BasicTests.FlakyTest" --duration 30

# Run for 10 minutes with 4 processes
gflake run <path-to-your-gtest-binary> --duration 600 --processes 4

# Run without parallelisation
gflake run <path-to-your-gtest-binary> --processes 1

Test Discovery

# List all available tests without running them
gflake discover <path-to-your-gtest-binary>

Finding Test Names for Direct Execution

Use the discover command to see all available test names in the exact format needed for the --test-name option:

Example output:

gflake discover cpp/build/test_binary

📁 BasicTests (3 tests)
├── 🧩 SimpleTest                   # Use: BasicTests.SimpleTest
└── 🧩 SlowTest                     # Use: BasicTests.SlowTest

📁 TypedTest/0 (2 tests) (typed)
├── 🧩 DefaultConstruction          # Use: TypedTest/0.DefaultConstruction
└── 🧩 Assignment                   # Use: TypedTest/0.Assignment

Understanding the Output

Session Summary

gFlake provides a comprehensive session summary table with the following metrics:

• Test Case: Full name of the test that was executed

• Progress: Real-time progress showing elapsed time vs target duration

• Time Remaining: Time left in the session

• Processes Used: Number of parallel processes utilized during execution

• Total Attempts: Total number of test runs executed during the session

• Successful Runs: Number of runs that passed successfully

• Failed Runs: Number of runs that failed

• Success Rate: Percentage of successful runs

• Throughput: Tests executed per second across all processes

• Median/Mean/Min/Max Time: Aggregated statistics for all test runs

Failure Analysis

• First few failures shown with full output
• All failures logged to failed_tests.log with timestamps

Log Files

Failed test runs are automatically logged to failed_tests.log:

================================================================================
gFlake Session: 2025-07-31 21:17:44
Total Failed Runs: 3157
================================================================================

FAILURE #1
————————————————————————————————————————
Return Code: 1
Duration: 3.7ms

Standard Output:
Running main() from /path/to/gtest_main.cc
/path/to/test.cpp:41: Failure
Failed
Simulated flaky test failure (random value: 1)

[  FAILED  ] BasicTests.FlakyTest (0 ms)
...

Development

# Install dependencies
poetry install

# Build sample C++ binary with gtest
mkdir -p cpp/build && cd cpp/build && cmake .. && cmake --build .

# Run Python tests
## Using Poetry
poetry run pytest tests/
## Using Makefile alias
make test-python

# Run C++ tests
## Using CMake
cd cpp/build && ctest
## Using Makefile alias
make test-cpp        # Without flaky test
make test-cpp-all    # With flaky test

# Use sample gtest binary
## Run using installed gflake
gflake run cpp/build/test_binary

## Run via poetry
poetry run gflake run cpp/build/test_binary

# Run linter
make lint-fix

# Run formatter
make format

Tips

• Start Small: Begin with short durations (30-60 seconds) to verify your setup
• Adjust Processes: Use --processes to match your system capabilities if the defaults (half of available cores) are not optimal.
  • If your tests share resources (e.g. database operations) or affect each other in any way, consider running with --processes 1 to avoid interference.
• Monitor Logs: Check failed_tests.log for detailed failure analysis
• Use Discovery: Run gflake discover to see all available tests