[AIRFLOW-6720] Detect missing tests for providers package

tests/test_project_structure.py

@@ -24,6 +24,41 @@
     os.path.join(os.path.dirname(os.path.realpath(__file__)), os.pardir)
 )
 
+MISSING_TEST_FILES = {
+    'tests/providers/amazon/aws/hooks/test_athena.py',
+    'tests/providers/amazon/aws/hooks/test_s3.py',
+    'tests/providers/apache/cassandra/sensors/test_record.py',
+    'tests/providers/apache/cassandra/sensors/test_table.py',
+    'tests/providers/apache/hdfs/sensors/test_web_hdfs.py',
+    'tests/providers/apache/hive/operators/test_vertica_to_hive.py',
+    'tests/providers/apache/hive/sensors/test_hive_partition.py',
+    'tests/providers/apache/hive/sensors/test_metastore_partition.py',
+    'tests/providers/apache/pig/operators/test_pig.py',
+    'tests/providers/apache/spark/hooks/test_spark_jdbc_script.py',
+    'tests/providers/cncf/kubernetes/operators/test_kubernetes_pod.py',
+    'tests/providers/google/cloud/operators/test_datastore.py',
+    'tests/providers/google/cloud/operators/test_gcs_to_bigquery.py',
+    'tests/providers/google/cloud/operators/test_sql_to_gcs.py',
+    'tests/providers/google/cloud/sensors/test_bigquery.py',
+    'tests/providers/google/cloud/utils/test_field_sanitizer.py',
+    'tests/providers/google/cloud/utils/test_field_validator.py',
+    'tests/providers/google/cloud/utils/test_mlengine_operator_utils.py',
+    'tests/providers/google/cloud/utils/test_mlengine_prediction_summary.py',
+    'tests/providers/jenkins/hooks/test_jenkins.py',
+    'tests/providers/microsoft/azure/sensors/test_azure_cosmos.py',
+    'tests/providers/microsoft/mssql/hooks/test_mssql.py',
+    'tests/providers/microsoft/mssql/operators/test_mssql.py',
+    'tests/providers/oracle/operators/test_oracle.py',
+    'tests/providers/presto/operators/test_presto_check.py',
+    'tests/providers/qubole/hooks/test_qubole.py',
+    'tests/providers/samba/hooks/test_samba.py',
+    'tests/providers/snowflake/hooks/test_snowflake.py',
+    'tests/providers/snowflake/operators/test_s3_to_snowflake.py',
+    'tests/providers/snowflake/operators/test_snowflake.py',
+    'tests/providers/sqlite/operators/test_sqlite.py',
+    'tests/providers/vertica/hooks/test_vertica.py'
+}
+
 
 class TestProjectStructure(unittest.TestCase):
     def test_reference_to_providers_from_core(self):
@@ -49,3 +84,53 @@ def assert_file_contains(self, filename: str, pattern: str):
         with open(filename, 'rb', 0) as file, mmap.mmap(file.fileno(), 0, access=mmap.ACCESS_READ) as content:
             if content.find(bytes(pattern, 'utf-8')) == -1:
                 self.fail(f"File {filename} contains illegal pattern - {pattern}")
+
+    def test_providers_modules_should_have_tests(self):
+        """
+        Assert every module in /airflow/providers has a corresponding test_ file in tests/airflow/providers.
+        """
+        # TODO: Should we extend this test to cover other directories?
+        expected_test_files = glob.glob(f"{ROOT_FOLDER}/airflow/providers/**/*.py", recursive=True)
+        # Make path relative
+        expected_test_files = (os.path.relpath(f, ROOT_FOLDER) for f in expected_test_files)
+        # Exclude example_dags
+        expected_test_files = (f for f in expected_test_files if "/example_dags/" not in f)
+        # Exclude __init__.py
+        expected_test_files = (f for f in expected_test_files if not f.endswith("__init__.py"))
+        # Change airflow/ to tests/
+        expected_test_files = (
+            f'tests/{f.partition("/")[2]}'
+            for f in expected_test_files if not f.endswith("__init__.py")
+        )
+        # Add test_ prefix to filename
+        expected_test_files = (
+            f'{f.rpartition("/")[0]}/test_{f.rpartition("/")[2]}'
+            for f in expected_test_files if not f.endswith("__init__.py")
+        )
+
+        current_test_files = glob.glob(f"{ROOT_FOLDER}/tests/providers/**/*.py", recursive=True)
+        # Make path relative
+        current_test_files = (os.path.relpath(f, ROOT_FOLDER) for f in current_test_files)
+        # Exclude __init__.py
+        current_test_files = (f for f in current_test_files if not f.endswith("__init__.py"))
+
+        expected_test_files = set(expected_test_files)
+        current_test_files = set(current_test_files)
+
+        missing_tests_files = expected_test_files - expected_test_files.intersection(current_test_files)
+        self.assertEqual(set(), missing_tests_files - MISSING_TEST_FILES)
+
+    def test_keep_missing_test_files_update(self):
+        new_test_files = []
+        for test_file in MISSING_TEST_FILES:
+            if os.path.isfile(f"{ROOT_FOLDER}/{test_file}"):
+                new_test_files.append(test_file)
+        if new_test_files:
+            new_files_text = '\n'.join(new_test_files)
+            self.fail(
+                "You've added a test file currently listed as missing:\n"
+                f"{new_files_text}"
+                "\n"
+                "Thank you very much.\n"
+                "Can you remove it from the list of missing tests, please?"
+            )