diff --git a/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/__init__.py b/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/__init__.py
new file mode 100644
index 00000000..f757e54c
--- /dev/null
+++ b/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/__init__.py
@@ -0,0 +1,5 @@
+# #590: a subpackage that turns itself into a module from elsewhere on sys.path.
+I_AM = "the subpackage that was replaced with a system module"
+import sys
+import system_distro
+sys.modules[__name__] = system_distro
diff --git a/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/_distro.py b/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/_distro.py
new file mode 100644
index 00000000..16c32b2a
--- /dev/null
+++ b/tests/data/importer/pkg_like_ansible/module_utils/sys_distro/_distro.py
@@ -0,0 +1 @@
+I_AM = "the module inside the replaced subpackage"
diff --git a/tests/data/importer/system_distro.py b/tests/data/importer/system_distro.py
new file mode 100644
index 00000000..78fb1601
--- /dev/null
+++ b/tests/data/importer/system_distro.py
@@ -0,0 +1,2 @@
+# #590: a system module that replaces some subpackage
+I_AM = "the system module that replaced the subpackage"
diff --git a/tests/responder_test.py b/tests/responder_test.py
index 60817747..2653589c 100644
--- a/tests/responder_test.py
+++ b/tests/responder_test.py
@@ -159,7 +159,6 @@ class BrokenModulesTest(testlib.TestCase):
 
         self.assertEquals(1, responder.get_module_count)
         self.assertEquals(1, responder.good_load_module_count)
-        self.assertEquals(7642, responder.good_load_module_size)
         self.assertEquals(0, responder.bad_load_module_count)
 
         call = router._async_route.mock_calls[0]