create-python-tests

# Creating Python Unit Tests for a Data Product When a new data product is created or updated, you **MUST** create a corresponding Python unit test using `pytest`. This test ensures that the compiled SQL query correctly implements the business logic, transformations, joins, and filtering criteria documented in the implementation plan. --- ## Workflow ### Step 1: Analyze the Implementation Plan and Code 1. **Retrieve Assumptions & Transformations:** Read the implementation plan (from `/create-data-product`) to identify: * Which source tables are joined (e.g., `KNA1` and `ADRC`). * What filtering rules are applied (e.g., `mandt = '100'`, specific system versions). * What columns are expected and how they are transformed (e.g., coalesced fields, calculations). 2. **Locate Scaffolding Files:** Locate the custom data product's definition file (`src/data_modules/<namespace>/<source>/products/<type>/definitions/*.js`). 3. **Leverage SAP & Domain Knowledge (CRITICAL):** Apply your technical understanding of SAP DDIC structures (e.g., how client-specific data is separated, document lines vs headers, translation checks) and the business domain (e.g., Order-to-Cash, Procure-to-Pay, General Ledger) to design meaningful assertions. If any transformations or business rules are complex, custom, or ambiguous, you **MUST** ask the user for clarifying inputs on how those requirements should be verified in the unit tests before writing the test file. ### Step 2: Scaffold the Test File 1. **Test Location:** Create the test file under `tests/unit/<namespace>/` named `test_<type>.py`. 2. **Template Reference:** Use the base test template in [test_template.py.md](assets/test_template.py.md) to structure the test file. ### Step 3: Implement Test Assertions Write assertions to verify the following from the compiled query: 1. **Join Logic Verification:** Parse the query to assert that the correct source tables are joined on the appropriate keys. * *Example:* Verify that `KNA1` is joined with `ADRC` on `kunnr`. 2. **Filter Logic Verification:** Assert that filtering constraints from the user profile or assumptions are present in the SQL. * *Example:* Verify that `mandt = '100'` or `mandt = "100"` is enforced in the `WHERE` or `ON` clauses. 3. **Field Transformations Verification:** Verify that specific aliased or transformed fields exist in the SELECT statement. * *Example:* Verify that `COALESCE` is used on postal code fields or region fields. 4. **Important Field Existence Verification:** Verify that key or important fields (like primary keys, key foreign relations, and required business dimensions) are actively selected and projected in the final SQL statement. * *Example:* Verify that fields like `customer_number_kunnr` or `valid_from_date` are selected. 5. **Custom Z-Fields Assertions:** If the data product maps custom SAP fields (Z-fields, ZZ-fields, or YY-fields), write explicit assertions to verify that these custom columns are correctly projected in the SELECT query and adhere to the snake_case description mapping convention (e.g., asserting that `'zz_'` or `'yy_'` matches are present). ### Step 4: Run the Unit Tests 1. Compile the workspace first: `uv run cortex-build --config config/config.yaml`. 2. Execute the unit tests using `pytest`. You **MUST** run the targeted test file for your custom data product to verify assertions quickly and efficiently: ```bash uv run pytest tests/unit/<namespace>/test_<type>.py -s ``` 3. **If any Test Fails:** Fix the query definitions, configs, or test assertions and recompile/retest until the targeted test passes cleanly. 4. **Full Suite Verification (CRITICAL):** Once the targeted test passes, you **MUST** run the entire suite (`uv run pytest`) to ensure you haven't broken any other existing tests or core functionalities. ALL available unit tests must pass. --- ## 📊 Quality Gate Integration Any Python unit tests created with this skill must be included in the **Final Quality Report** as part of the Quality Gate execution. Report the number of unit tests executed, passed, and failed.