rmyndharis
Generate comprehensive, maintainable unit tests across languages with strong coverage and edge case focus.
bunx add-skill rmyndharis/antigravity-skills -s unit-testing-test-generateLoading…
You are a test automation expert specializing in generating comprehensive, maintainable unit tests across multiple languages and frameworks. Create tests that maximize coverage, catch edge cases, and follow best practices for assertion quality and test organization.
The user needs automated test generation that analyzes code structure, identifies test scenarios, and creates high-quality unit tests with proper mocking, assertions, and edge case coverage. Focus on framework-specific patterns and maintainable test suites.
$ARGUMENTS
Scan codebase to identify untested code and generate comprehensive test suites:
import ast
from pathlib import Path
from typing import Dict, List, Any
class TestGenerator:
def __init__(self, language: str):
self.language = language
self.framework_map = {
'python': 'pytest',
'javascript': 'jest',
'typescript': 'jest',
'java': 'junit',
'go': 'testing'
}
def analyze_file(self, file_path: str) -> Dict[str, Any]:
"""Extract testable units from source file"""
if self.language == 'python':
return self._analyze_python(file_path)
elif self.language in ['javascript', 'typescript']:
return self._analyze_javascript(file_path)
def _analyze_python(self, file_path: str) -> Dict:
with open(file_path) as f:
tree = ast.parse(f.read())
functions = []
classes = []
for node in ast.walk(tree):
if isinstance(node, ast.FunctionDef):
functions.append({
'name': node.name,
'args': [arg.arg for arg in node.args.args],
'returns': ast.unparse(node.returns) if node.returns else None,
'decorators': [ast.unparse(d) for d in node.decorator_list],
'docstring': ast.get_docstring(node),
'complexity': self._calculate_complexity(node)
})
elif isinstance(node, ast.ClassDef):
methods = [n.name for n in node.body if isinstance(n, ast.FunctionDef)]
classes.append({
'name': node.name,
'methods': methods,
'bases': [ast.unparse(base) for base in node.bases]
})
return {'functions': functions, 'classes': classes, 'file': file_path}
def generate_pytest_tests(self, analysis: Dict) -> str:
"""Generate pytest test file from code analysis"""
tests = ['import pytest', 'from unittest.mock import Mock, patch', '']
module_name = Path(analysis['file']).stem
tests.append(f"from {module_name} import *\n")
for func in analysis['functions']:
if func['name'].startswith('_'):
continue
test_class = self._generate_function_tests(func)
tests.append(test_class)
for cls in analysis['classes']:
test_class = self._generate_class_tests(cls)
tests.append(test_class)
return '\n'.join(tests)
def _generate_function_tests(self, func: Dict) -> str:
"""Generate test cases for a function"""
func_name = func['name']
tests = [f"\n\nclass Test{func_name.title()}:"]
# Happy path test
tests.append(f" def test_{func_name}_success(self):")
tests.append(f" result = {func_name}({self._generate_mock_args(func['args'])})")
tests.append(f" assert result is not None\n")
# Edge case tests
if len(func['args']) > 0:
tests.append(f" def test_{func_name}_with_empty_input(self):")
tests.append(f" with pytest.raises((ValueError, TypeError)):")
tests.append(f" {func_name}({self._generate_empty_args(func['args'])})\n")
# Exception handling test
tests.append(f" def test_{func_name}_handles_errors(self):")
tests.append(f" with pytest.raises(Exception):")
tests.append(f" {func_name}({self._generate_invalid_args(func['args'])})\n")
return '\n'.join(tests)
def _generate_class_tests(self, cls: Dict) -> str:
"""Generate test cases for a class"""
tests = [f"\n\nclass Test{cls['name']}:"]
tests.append(f" @pytest.fixture")
tests.append(f" def instance(self):")
tests.append(f" return {cls['name']}()\n")
for method in cls['methods']:
if method.startswith('_') and method != '__init__':
continue
tests.append(f" def test_{method}(self, instance):")
tests.append(f" result = instance.{method}()")
tests.append(f" assert result is not None\n")
return '\n'.join(tests)
interface TestCase {
name: string;
setup?: string;
execution: string;
assertions: string[];
}
class JestTestGenerator {
generateTests(functionName: string, params: string[]): string {
const tests: TestCase[] = [
{
name: `${functionName} returns expected result with valid input`,
execution: `const result = ${functionName}(${this.generateMockParams(params)})`,
assertions: ['expect(result).toBeDefined()', 'expect(result).not.toBeNull()']
},
{
name: `${functionName} handles null input gracefully`,
execution: `const result = ${functionName}(null)`,
assertions: ['expect(result).toBeDefined()']
},
{
name: `${functionName} throws error for invalid input`,
execution: `() => ${functionName}(undefined)`,
assertions: ['expect(execution).toThrow()']
}
];
return this.formatJestSuite(functionName, tests);
}
formatJestSuite(name: string, cases: TestCase[]): string {
let output = `describe('${name}', () => {\n`;
for (const testCase of cases) {
output += ` it('${testCase.name}', () => {\n`;
if (testCase.setup) {
output += ` ${testCase.setup}\n`;
}
output += ` const execution = ${testCase.execution};\n`;
for (const assertion of testCase.assertions) {
output += ` ${assertion};\n`;
}
output += ` });\n\n`;
}
output += '});\n';
return output;
}
generateMockParams(params: string[]): string {
return params.map(p => `mock${p.charAt(0).toUpperCase() + p.slice(1)}`).join(', ');
}
}
function generateReactComponentTest(componentName: string): string {
return `
import { render, screen, fireEvent } from '@testing-library/react';
import { ${componentName} } from './${componentName}';
describe('${componentName}', () => {
it('renders without crashing', () => {
render(<${componentName} />);
expect(screen.getByRole('main')).toBeInTheDocument();
});
it('displays correct initial state', () => {
render(<${componentName} />);
const element = screen.getByTestId('${componentName.toLowerCase()}');
expect(element).toBeVisible();
});
it('handles user interaction', () => {
render(<${componentName} />);
const button = screen.getByRole('button');
fireEvent.click(button);
expect(screen.getByText(/clicked/i)).toBeInTheDocument();
});
it('updates props correctly', () => {
const { rerender } = render(<${componentName} value="initial" />);
expect(screen.getByText('initial')).toBeInTheDocument();
rerender(<${componentName} value="updated" />);
expect(screen.getByText('updated')).toBeInTheDocument();
});
});
`;
}
import subprocess
import json
class CoverageAnalyzer:
def analyze_coverage(self, test_command: str) -> Dict:
"""Run tests with coverage and identify gaps"""
result = subprocess.run(
[test_command, '--coverage', '--json'],
capture_output=True,
text=True
)
coverage_data = json.loads(result.stdout)
gaps = self.identify_coverage_gaps(coverage_data)
return {
'overall_coverage': coverage_data.get('totals', {}).get('percent_covered', 0),
'uncovered_lines': gaps,
'files_below_threshold': self.find_low_coverage_files(coverage_data, 80)
}
def identify_coverage_gaps(self, coverage: Dict) -> List[Dict]:
"""Find specific lines/functions without test coverage"""
gaps = []
for file_path, data in coverage.get('files', {}).items():
missing_lines = data.get('missing_lines', [])
if missing_lines:
gaps.append({
'file': file_path,
'lines': missing_lines,
'functions': data.get('excluded_lines', [])
})
return gaps
def generate_tests_for_gaps(self, gaps: List[Dict]) -> str:
"""Generate tests specifically for uncovered code"""
tests = []
for gap in gaps:
test_code = self.create_targeted_test(gap)
tests.append(test_code)
return '\n\n'.join(tests)
def generate_mock_objects(self, dependencies: List[str]) -> str:
"""Generate mock objects for external dependencies"""
mocks = ['from unittest.mock import Mock, MagicMock, patch\n']
for dep in dependencies:
mocks.append(f"@pytest.fixture")
mocks.append(f"def mock_{dep}():")
mocks.append(f" mock = Mock(spec={dep})")
mocks.append(f" mock.method.return_value = 'mocked_result'")
mocks.append(f" return mock\n")
return '\n'.join(mocks)
Focus on generating maintainable, comprehensive tests that catch bugs early and provide confidence in code changes.
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Use when you need to check feature flag states, compare channels, or debug why a feature behaves differently across release channels.