Add policy_eval_script/tests/test_core.py

policy_eval_script/tests/test_core.py

@@ -0,0 +1,73 @@
+import json
+import hashlib
+import pytest
+from pathlib import Path
+
+# Modul unter Test
+def _import_evaluate_policy():
+    import importlib.util
+    import sys
+    core_path = Path('src/policy_eval_script/core.py')
+    spec = importlib.util.spec_from_file_location('policy_eval_script.core', core_path)
+    module = importlib.util.module_from_spec(spec)
+    sys.modules['policy_eval_script.core'] = module
+    spec.loader.exec_module(module)
+    return module.evaluate_policy
+
+@pytest.fixture(scope='module')
+def evaluate_policy():
+    return _import_evaluate_policy()
+
+@pytest.fixture
+def sample_policy_constants(tmp_path):
+    constants = {"alpha_threshold": 0.05, "beta": 0.1}
+    path = tmp_path / 'policy_constants.json'
+    path.write_text(json.dumps(constants))
+    return path, constants
+
+@pytest.fixture
+def sample_drift_report():
+    return {
+        'stratum_A': {'drift_score': 0.03},
+        'stratum_B': {'drift_score': 0.08}
+    }
+
+def _expected_hash(constants: dict) -> str:
+    const_str = json.dumps(constants, sort_keys=True)
+    return hashlib.sha256(const_str.encode('utf-8')).hexdigest()
+
+def test_evaluate_policy_pass_case(evaluate_policy, sample_drift_report, sample_policy_constants, monkeypatch):
+    _, constants = sample_policy_constants
+    policy_hash = _expected_hash(constants)
+
+    monkeypatch.setattr('src.policy_eval_script.core._load_policy_constants', lambda: constants)
+    result = evaluate_policy(sample_drift_report)
+
+    assert isinstance(result, dict)
+    assert set(result.keys()) >= {'stratum', 'decision', 'reason', 'policy_hash'}
+    assert result['policy_hash'] == policy_hash
+    assert result['decision'] in {'PASS', 'WARN', 'FAIL'}
+    assert isinstance(result['reason'], str)
+
+def test_evaluate_policy_fail_case(evaluate_policy, sample_policy_constants, monkeypatch):
+    report = {'stratum_C': {'drift_score': 0.2}}
+    _, constants = sample_policy_constants
+    constants['alpha_threshold'] = 0.05
+
+    monkeypatch.setattr('src.policy_eval_script.core._load_policy_constants', lambda: constants)
+    result = evaluate_policy(report)
+
+    assert result['decision'] == 'FAIL'
+    assert 'drift_score' in result['reason']
+
+def test_invalid_input_validation(evaluate_policy):
+    with pytest.raises(AssertionError):
+        evaluate_policy('not_a_dict')
+
+def test_evaluate_policy_structure_is_complete(evaluate_policy, sample_drift_report, sample_policy_constants, monkeypatch):
+    _, constants = sample_policy_constants
+    monkeypatch.setattr('src.policy_eval_script.core._load_policy_constants', lambda: constants)
+
+    result = evaluate_policy(sample_drift_report)
+    for field in ('stratum', 'decision', 'reason', 'policy_hash'):
+        assert field in result, f'Missing field {field}'