py37: deal with Exception repr changes

Under Python 3.7, a trailing comma is no longer added to
the init parameters generated by a repr() call:

    >>> repr(Exception('It Works'))
    "Exception('It Works')"

vs

    >>> repr(Exception('It Works'))
    "Exception('It Works',)"

Support pre and post Python 3.7 formats in test cases.

Change-Id: Idff8c841fd6c489e887bd72b49e91ef6f0e2d4f3
Closes-Bug: #1784487

oslo_vmware/tests/test_exceptions.py

@@ -43,7 +43,8 @@ class ExceptionsTest(base.TestCase):
     def test_vim_fault_exception(self):
         vfe = exceptions.VimFaultException([ValueError("example")], _("cause"))
         string = str(vfe)
-        self.assertEqual("cause\nFaults: [ValueError('example',)]", string)
+        self.assertIn(string, ["cause\nFaults: [ValueError('example',)]",
+                               "cause\nFaults: [ValueError('example')]"])
 
     def test_vim_fault_exception_with_cause_and_details(self):
         vfe = exceptions.VimFaultException([ValueError("example")],
@@ -51,11 +52,14 @@ class ExceptionsTest(base.TestCase):
                                            "FooBar",
                                            {'foo': 'bar'})
         string = str(vfe)
-        self.assertEqual("MyMessage\n"
+        self.assertIn(string, ["MyMessage\n"
-                         "Cause: FooBar\n"
+                               "Cause: FooBar\n"
-                         "Faults: [ValueError('example',)]\n"
+                               "Faults: [ValueError('example',)]\n"
-                         "Details: {'foo': 'bar'}",
+                               "Details: {'foo': 'bar'}",
-                         string)
+                               "MyMessage\n"
+                               "Cause: FooBar\n"
+                               "Faults: [ValueError('example')]\n"
+                               "Details: {'foo': 'bar'}"])
 
     def _create_subclass_exception(self):
         class VimSubClass(exceptions.VimException):