feat: add customers data contract and validation tests

README.md

@@ -31,7 +31,7 @@ Scheduling options are documented in [`docs/scheduling.md`](docs/scheduling.md).
 
 ## Current capabilities
 
-- [x] YAML data contracts with column rules and foreign keys
+- [x] YAML data contracts with column rules and foreign keys (orders, customers)
 - [x] Schema validation against contract columns
 - [x] Null, uniqueness, freshness, and referential-integrity checks
 - [x] Check run history with SQLite (default) or PostgreSQL
@@ -101,7 +101,8 @@ python -m src.dqo.cli history --contract orders
 ├── dags/
 │   └── dqo_orders_checks.py
 ├── contracts/
-│   └── orders.yml
+│   ├── orders.yml
+│   └── customers.yml
 ├── data/samples/
 ├── docs/
 │   ├── architecture.md

contracts/customers.yml

@@ -0,0 +1,15 @@
+name: customers
+version: "1.0"
+description: Customer dimension contract for retail analytics
+
+columns:
+  customer_id:
+    type: string
+    nullable: false
+    unique: true
+  full_name:
+    type: string
+    nullable: false
+  region:
+    type: string
+    nullable: false

data/samples/customers_invalid.csv

@@ -0,0 +1,4 @@
+customer_id,full_name,region
+C001,Ada Lovelace,EMEA
+C001,Grace Hopper,AMER
+,Missing Name,APAC

tests/conftest.py

@@ -14,6 +14,11 @@ def orders_contract() -> object:
     return load_contract(ROOT / "contracts" / "orders.yml")
 
 
+@pytest.fixture
+def customers_contract() -> object:
+    return load_contract(ROOT / "contracts" / "customers.yml")
+
+
 @pytest.fixture
 def valid_orders() -> list[dict[str, str]]:
     return load_csv(ROOT / "data" / "samples" / "orders.csv")

tests/test_contracts.py

@@ -10,3 +10,16 @@ def test_load_orders_contract() -> None:
     assert contract.freshness is not None
     assert contract.freshness.column == "updated_at"
     assert len(contract.foreign_keys) == 1
+
+
+def test_load_customers_contract() -> None:
+    contract = load_contract(Path("contracts/customers.yml"))
+    assert contract.name == "customers"
+    assert contract.freshness is None
+    assert {column.name for column in contract.columns} == {
+        "customer_id",
+        "full_name",
+        "region",
+    }
+    customer_id_column = next(column for column in contract.columns if column.name == "customer_id")
+    assert customer_id_column.unique is True

tests/test_runner.py

@@ -23,3 +23,17 @@ def test_run_contract_file_fails_for_invalid_dataset(tmp_path: Path) -> None:
     )
     assert summary.passed is False
     assert summary.failed_results
+
+
+def test_run_checks_passes_for_valid_customers(customers_contract, customers) -> None:
+    results = run_checks(customers_contract, customers)
+    assert all(result.status.value != "failed" for result in results)
+
+
+def test_run_contract_file_fails_for_invalid_customers() -> None:
+    summary = run_contract_file(
+        Path("contracts/customers.yml"),
+        Path("data/samples/customers_invalid.csv"),
+    )
+    assert summary.passed is False
+    assert summary.failed_results