Expose a bug that list_limit doesn't work correctly

The list_limit for domain list doesn't work
correctly. The return count will less than
list_limit if the sql query contains root domain

This patch expose this bug and it will be fixed
in the following patch.

Co-Authored-By: Lance Bragstad<lbragstad@gmail.com>

Partial-bug: #1760521

Change-Id: Ib28793c97f1b730cb3b83b046e653a7b660af875

keystone/tests/unit/identity/test_backends.py

@@ -24,6 +24,7 @@ from keystone import exception
 from keystone.tests import unit
 from keystone.tests.unit import default_fixtures
 from keystone.tests.unit import filtering
+from keystone.tests.unit import utils as test_utils
 
 
 CONF = keystone.conf.CONF
@@ -1105,6 +1106,36 @@ class IdentityTests(object):
         self.assertThat(entities[1]['name'],
                         matchers.StartsWith('domaingroup1'))
 
+    @unit.skip_if_no_multiple_domains_support
+    @test_utils.wip('The root domain throws off the limit count by one',
+                    bug='#1760521')
+    def test_list_limit_for_domains(self):
+        def create_domains(count):
+            for _ in range(count):
+                domain = unit.new_domain_ref()
+                self.domain_list.append(
+                    PROVIDERS.resource_api.create_domain(domain['id'], domain))
+
+        def clean_up_domains():
+            for domain in self.domain_list:
+                PROVIDERS.resource_api.update_domain(
+                    domain['id'], {'enabled': False})
+                PROVIDERS.resource_api.delete_domain(domain['id'])
+
+        PROVIDERS.resource_api.create_domain(
+            default_fixtures.ROOT_DOMAIN['id'], default_fixtures.ROOT_DOMAIN
+        )
+
+        self.domain_list = []
+        create_domains(6)
+        self.addCleanup(clean_up_domains)
+
+        for x in range(1, 7):
+            self.config_fixture.config(group='resource', list_limit=x)
+            hints = driver_hints.Hints()
+            entities = PROVIDERS.resource_api.list_domains(hints=hints)
+            self.assertThat(entities, matchers.HasLength(hints.limit['limit']))
+
 
 class FilterTests(filtering.FilterTests):
     def test_list_entities_filtered(self):

keystone/tests/unit/test_backend_ldap.py

@@ -3044,6 +3044,12 @@ class DomainSpecificLDAPandSQLIdentity(
         self.skip_test_overrides(
             'Restricted multi LDAP class does not support multiple domains')
 
+    def test_list_limit_for_domains(self):
+        # With this restricted multi LDAP class, tests that use multiple
+        # domains and identity, are still not supported
+        self.skip_test_overrides(
+            'Restricted multi LDAP class does not support multiple domains')
+
 
 class DomainSpecificSQLIdentity(DomainSpecificLDAPandSQLIdentity):
     """Class to test simplest use of domain-specific SQL driver.

keystone/tests/unit/test_v3_resource.py

@@ -21,6 +21,7 @@ import keystone.conf
 from keystone.credential.providers import fernet as credential_fernet
 from keystone import exception
 from keystone.tests import unit
+from keystone.tests.unit import default_fixtures
 from keystone.tests.unit import ksfixtures
 from keystone.tests.unit import test_v3
 from keystone.tests.unit import utils as test_utils
@@ -150,6 +151,25 @@ class ResourceTestCase(test_v3.RestfulTestCase,
                                            resource_url=resource_url)
         self.head(resource_url, expected_status=http_client.OK)
 
+    @test_utils.wip('The root domain throws off the limit count by one',
+                    bug='#1760521')
+    def test_list_limit_for_domains(self):
+        PROVIDERS.resource_api.create_domain(
+            default_fixtures.ROOT_DOMAIN['id'], default_fixtures.ROOT_DOMAIN
+        )
+
+        for x in range(6):
+            domain = {'domain': unit.new_domain_ref()}
+            self.post('/domains', body=domain)
+
+        for expected_length in range(1, 6):
+            self.config_fixture.config(
+                group='resource', list_limit=expected_length
+            )
+            response = self.get('/domains')
+            domain_list = response.json_body['domains']
+            self.assertEqual(expected_length, len(domain_list))
+
     def test_get_head_domain(self):
         """Call ``GET /domains/{domain_id}``."""
         resource_url = '/domains/%(domain_id)s' % {