[bugfix] Fix assertRaises tests in api_tests.py

Bug: T267801
Change-Id: I42d3975ebd1363112e4b2f21cdc0b323065a839d
---
M tests/api_tests.py
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/tests/api_tests.py b/tests/api_tests.py
index 83db11b..6da76fa 100755
--- a/tests/api_tests.py
+++ b/tests/api_tests.py
@@ -475,10 +475,10 @@
 
     def test_namespace(self):
         """Test PageGenerator set_namespace."""
-        with self.assertRaises(AssertionError):
-            self.gen.set_namespace(0)
-            self.gen.set_namespace(1)
-            self.gen.set_namespace(None)
+        for namespace in (0, 1, None):
+            with self.subTest(namespace=namespace), \
+                 self.assertRaises(AssertionError):
+                self.gen.set_namespace(namespace)
 
 
 class TestPropertyGenerator(TestCase):
@@ -637,10 +637,10 @@
         self.gen = api.PageGenerator(site=self.site,
                                      generator='links',
                                      parameters={'titles': 'test'})
-        with self.assertRaises(AssertionError):
-            self.gen.set_namespace(0)
-            self.gen.set_namespace(1)
-            self.gen.set_namespace(None)
+        for namespace in (0, 1, None):
+            with self.subTest(namespace=namespace), \
+                 self.assertRaises(AssertionError):
+                self.gen.set_namespace(namespace)
 
     @suppress_warnings(
         r'^set_namespace\(\) will be modified to raise TypeError*',

