Fix db API get_ids_for_all_tests

This commit fix the get_ids_for_all_tests API typo
and update the docstring.

Story: #2000580
Change-Id: Iaefac14153fa7fcae9e05ccf7e8ced5e63f2a9c6

releasenotes/notes/fix-get_ids_for_all_tests-typo-and-update-the-docstring-552735ca593c4613.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - Fix the get_ids_for_all_tests API typo and
+    update the docstring. (Story 2000580)

subunit2sql/db/api.py

@@ -1157,15 +1157,15 @@ def get_id_from_test_id(test_id, session=None):
 
 
 def get_ids_for_all_tests(session=None):
-    """Return a list of ids (uuid primary key) for all tests in the database
+    """Return an iterator of ids (uuid primary key) for all tests in the database
 
     :param session: Optional session object if one isn't provided a new session
                     will be acquired for the duration of this operation
-    :return: The list of all ids for tests in the tests table
-    :rtype: list
+    :return: The iterator of all ids for tests in the tests table
+    :rtype: iterator
     """
     session = session or get_session()
-    return db_utils.model_query(models.Test, session).value(models.Test.id)
+    return db_utils.model_query(models.Test, session).values(models.Test.id)
 
 
 def get_run_times_grouped_by_run_metadata_key(key, start_date=None,

subunit2sql/tests/db/test_api.py

@@ -13,6 +13,7 @@
 # under the License.
 
 import datetime
+import types
 
 from six import moves
 import testscenarios
@@ -1010,3 +1011,14 @@ class TestDatabaseAPI(base.TestCase):
         self.assertIn('attach_label_a', [x.label for x in res])
         self.assertIn(b'attach', [x.attachment for x in res])
         self.assertIn(b'attach_a', [x.attachment for x in res])
+
+    def test_get_ids_for_all_tests(self):
+        test_a = api.create_test('fake_test')
+        test_b = api.create_test('fake_test1')
+        test_c = api.create_test('fake_test2')
+        res = api.get_ids_for_all_tests()
+        self.assertIsInstance(res, types.GeneratorType)
+        res = list(res)
+        self.assertIn((test_c.id,), res)
+        self.assertIn((test_b.id,), res)
+        self.assertIn((test_a.id,), res)