How to make Claude 3.7 Opus write production-grade unit tests in one prompt

Copy this 100% working prompt to get Claude 3.7 Opus to write production quality, fully tested unit tests for any codebase in 10 seconds.

✅ The Working Prompt

Write full production-grade unit tests for this code:
[PASTE YOUR CODE HERE]

Requirements:
1. 100% test coverage for all branches, edge cases, error paths
2. Use native test framework (Jest for JS, pytest for Python, etc.)
3. Include all necessary mock/stub setup
4. Add descriptive test names in "should [behavior] when [condition]" format
5. Include comments explaining every test case
6. No pseudo-code, only fully runnable production code
	

💡 Pro Tips

• ✅ Add your package.json/pyproject.toml to the context so Claude uses correct dependency versions
• ✅ Ask it to output the full test command you can run directly
• ✅ For existing codebases, let it read your existing test files to match your team's style