altimate-code: Skill for OpenCode

dbt Testing

Requirements

Agent: builder or migrator (requires file write access) Tools used: bash (runs altimate-dbt commands), read, glob, write, edit, altimate_core_testgen, altimate_core_validate

When to Use This Skill

Use when the user wants to:

• Add tests to a model's schema.yml (unique, not_null, relationships, accepted_values)
• Write dbt unit tests (mock inputs → expected outputs)
• Create custom generic or singular tests
• Debug why a test is failing
• Practice test-driven development in dbt

Do NOT use for:

• Creating or modifying model SQL → use dbt-develop
• Writing model descriptions → use dbt-docs
• Debugging build/compilation errors → use dbt-troubleshoot

The Iron Rule

Never modify a test to make it pass without understanding why it's failing.

A failing test is information. It means either:

1. The data has a real quality issue (fix the data or the model)
2. The test expectation is wrong (update the test with justification)
3. The model logic is wrong (fix the model)

Option 2 requires explicit user confirmation. Do not silently weaken tests.

Schema Test Workflow

1. Discover Columns

altimate-dbt columns --model <name>
altimate-dbt column-values --model <name> --column <col>

2. Read Existing Tests

glob models/**/*schema*.yml models/**/*_models.yml
read <yaml_file>

3. Generate Tests

Auto-generate with altimate_core_testgen: Pass the compiled SQL and schema to generate boundary-value, NULL-handling, and edge-case test assertions automatically. This produces executable test SQL covering cases you might miss manually.

altimate_core_testgen(sql: <compiled_sql>, schema_context: <schema_object>)

Review the generated tests — keep what makes sense, discard trivial ones. Then apply test rules based on column patterns — see references/schema-test-patterns.md.

4. Write YAML

Merge into existing schema.yml (don't duplicate). Use edit for existing files, write for new ones.