[kvlonge]

Why

Model unit tests can mock relation dependencies but currently must deploy every table function used by the model. That prevents isolated model testing when a table function depends on warehouse-only inputs or dialect-specific implementation details.

Changes

• add __table_fn__<name> CTE fixtures to model-mode SQL tests
• replace the complete table-function invocation, including nested argument SQL, with the fixture relation
• validate fixture names, preserve helper CTE visibility, report unreachable fixtures, and expose them in plan inspection
• omit mocked table functions from test execution dependencies while leaving direct mode table_fn tests unchanged
• cover SQL-analysis and textual assembly, nested calls, assertions, comments and literals, invalid names, and real DuckDB execution

Verification

• uv sync --all-extras
• make check-ci
• focused Python suite: 127 passed
• DuckDB end-to-end model test with a table-function fixture
• independent review and focused follow-up verification
• cache-free compile against a large downstream project with five representative non-empty fixtures: 0 errors, 0 warnings
• public repository hygiene scan