YAML Tests (Schema-bound)

Schema-bound tests live in models/*.yml or models/**/schema.yml and complement (or replace) project.yml-based tests.

Example

# examples/r1_demo/models/users_enriched.yml
version: 1
models:
  - name: users_enriched
    description: "Adds gmail flag"
    columns:
      - name: id
        tests:
          - not_null: { severity: error }
          - unique
      - name: email
        tests:
          - not_null
          - accepted_values:
              values: ["a@example.com","b@example.com","c@gmail.com"]
              severity: warn
      - name: user_id
        tests:
          - relationships:
              to: ref('dim_users')
              field: user_id
              to_field: id
````

### Severities

* `error` → contributes to failures (exit code 2).
* `warn` → surfaced in summary as ❕, does not affect exit code.

### Run

```bash
fft test examples/r1_demo --env dev
# Select only tests tagged 'reconcile' (if present)
fft test examples/r1_demo --env dev --select tag:reconcile

Output (excerpt)

Data Quality Summary
────────────────────
✅ not_null           users.id                               (3ms)
❌ unique             users.id                               (2ms)
   ↳ [unique] users.id: found 1 duplicate
❕ accepted_values     users_enriched.email                   (1ms)

Totals
──────
✓ passed: 2
✗ failed: 1
! warnings: 1

Relationships (Foreign Keys)

Use the relationships test to assert that every value in a child column exists in a parent table. When declared under a column, the column name becomes the default field. The to parameter may point to another model via ref('model_name'), giving you fully-qualified database identifiers that match the current target profile. Optional filters (where, to_where) let you scope the child or parent sides independently.