write-tests

name	write-tests
description	Write or update unit tests for changed code, following project conventions and ensuring coverage meets the 80% threshold.

Write Tests

Steps

1. Identify what to test

Read the source module(s). Focus on:

• Public functions and CLI command handlers
• Branches: error paths, edge cases, validation
• New or changed behavior

Skip: third-party internals, Streamlit UI, trivial pass-throughs.

2. Locate or create test file

Tests in tests/ mirror source modules:

Source	Test file
src/databao_cli/commands/init.py	tests/test_init.py
src/databao_cli/commands/build.py	tests/test_build.py
src/databao_cli/mcp/tools/<name>.py	tests/test_mcp.py
src/databao_cli/commands/datasource/add.py	tests/test_add_datasource.py

Add to existing file when possible.

3. Conventions

• pytest only, no unittest.TestCase.
• Use project_layout fixture for project dirs, tmp_path for filesystem.
• CLI: click.testing.CliRunner, import cli from databao_cli.__main__.
• One behavior per test: test_<action>_<scenario>.
• Return type -> None on all test functions.
• Mock external I/O, not internal modules.

4. Write tests (Arrange/Act/Assert)

Specific assertions over truthiness. Include context:

assert result.exit_code == 0, f"Expected success but got: {result.output}"

5. Run and verify

uv run pytest tests/test_<module>.py -v
make test-cov-check

Repeat until 80% threshold met.

6. Lint

Run make check. Fix ruff/mypy errors in test code.