1 files changed, 22 insertions, 2 deletions
diff --git a/Lib/test/test_pyclbr.py b/Lib/test/test_pyclbr.py
index 9e970d9..839c58f 100644
--- a/Lib/test/test_pyclbr.py
+++ b/Lib/test/test_pyclbr.py
@@ -10,6 +10,7 @@ from types import FunctionType, MethodType, BuiltinFunctionType
 import pyclbr
 from unittest import TestCase, main as unittest_main
 from test import support
+from test.test_importlib import util as test_importlib_util
 from functools import partial
 
 StaticMethodType = type(staticmethod(lambda: None))
@@ -235,11 +236,30 @@ class PyclbrTest(TestCase):
         cm('email.parser')
         cm('test.test_pyclbr')
 
-    def test_issue_14798(self):
+
+class ReadmoduleTests(TestCase):
+
+    def setUp(self):
+        self._modules = pyclbr._modules.copy()
+
+    def tearDown(self):
+        pyclbr._modules = self._modules
+
+
+    def test_dotted_name_not_a_package(self):
         # test ImportError is raised when the first part of a dotted name is
-        # not a package
+        # not a package.
+        #
+        # Issue #14798.
         self.assertRaises(ImportError, pyclbr.readmodule_ex, 'asyncore.foo')
 
+    def test_module_has_no_spec(self):
+        module_name = "doesnotexist"
+        assert module_name not in pyclbr._modules
+        with test_importlib_util.uncache(module_name):
+            with self.assertRaises(ModuleNotFoundError):
+                pyclbr.readmodule_ex(module_name)
+
 
 if __name__ == "__main__":
     unittest_main()