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Sarj Code Standards

production-derived-test-cases

Warn when pytest membership-contract cases are derived only from the first-party production collection.

SARJ409 Rule source Tests Catalog JSON

Why

When exact eligibility or support membership is contractual, deriving cases from production lets a member change without an independent test oracle failing.

Fix

For contractual membership, define a literal expected table, assert the production collection equals it, and drive behavior from the expected table. Suppress the warning with rationale for an intentional dynamic sweep.

Examples

Before — flagged Do not derive cases from production eligibility
app/tests/test_models.py
import pytest
from app.models import ELIGIBLE_MODELS




@pytest.mark.parametrize("model", ELIGIBLE_MODELS)
def test_model(model):
    assert build(model).tier == "priority"
After — preferred Drive behavior from an independent expected table
app/tests/test_models.py
import pytest
from app.models import ELIGIBLE_MODELS


EXPECTED_MODELS = ("a", "b")




def test_model_membership():
    assert ELIGIBLE_MODELS == EXPECTED_MODELS




@pytest.mark.parametrize("model", EXPECTED_MODELS)
def test_model(model):
    assert build(model).tier == "priority"
Before — flagged A fixture equality does not observe the imported production collection
app/tests/test_models.py
import pytest
from app.models import ELIGIBLE_MODELS




def test_membership(ELIGIBLE_MODELS):
    assert ELIGIBLE_MODELS == ("a", "b")




@pytest.mark.parametrize("model", ELIGIBLE_MODELS)
def test_model(model):
    assert build(model)
After — preferred A fresh local expected table observes the actual production collection
app/tests/test_models.py
import pytest
from app.models import ELIGIBLE_MODELS




def test_membership():
    expected = ["a", "b"]
    assert ELIGIBLE_MODELS == expected




@pytest.mark.parametrize("model", ELIGIBLE_MODELS)
def test_model(model):
    assert build(model)