Make find_owners_test.py pass consistently.

The finder.owners_queue contains a set of owners but they appear in an
arbitrary order on each invocation of the test. The current method of
assertEqual() with a list fails randomly because of the ordering being
different.

Example: https://ci.chromium.org/p/infra/builders/try/Depot%20Tools%20Presubmit%20(win)/b8897976148721436512

This changes comparisons of owners_queue to use an assertEqualSets()
which does a comparison that is order-independent.

Change-Id: Ia827795af283dadeb56f76ae0cf14fa4ad7e9eeb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1895699
Reviewed-by: Aaron Gable <agable@chromium.org>
Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>

tests/owners_finder_test.py

@@ -132,7 +132,11 @@ class _BaseTestCase(unittest.TestCase):
 
 class OwnersFinderTests(_BaseTestCase):
   def test_constructor(self):
-    self.assertNotEquals(self.defaultFinder(), None)
+    self.assertNotEqual(self.defaultFinder(), None)
+
+  # A surrogate for the python 3 assertCountEqual() method.
+  def assertCountEqual(self, a, b):
+    self.assertEqual(sorted(a), sorted(b))
 
   def test_skip_files_owned_by_reviewers(self):
     files = [
@@ -155,8 +159,8 @@ class OwnersFinderTests(_BaseTestCase):
     i = 0
     while i < 2:
       i += 1
-      self.assertEqual(finder.owners_queue,
-                       [brett, john, darin, peter, ken, ben, tom])
+      self.assertCountEqual(finder.owners_queue,
+                            [brett, john, darin, peter, ken, ben, tom])
       self.assertEqual(finder.unreviewed_files, {
           'base/vlog.h',
           'chrome/browser/defaults.h',
@@ -192,7 +196,7 @@ class OwnersFinderTests(_BaseTestCase):
 
     finder = self.defaultFinder()
     finder.select_owner(darin)
-    self.assertEqual(finder.owners_queue, [brett, peter, ken, ben, tom])
+    self.assertCountEqual(finder.owners_queue, [brett, peter, ken, ben, tom])
     self.assertEqual(finder.selected_owners, {darin})
     self.assertEqual(finder.deselected_owners, {john})
     self.assertEqual(finder.reviewed_by, {'content/bar/foo.cc': darin,
@@ -204,7 +208,7 @@ class OwnersFinderTests(_BaseTestCase):
 
     finder = self.defaultFinder()
     finder.select_owner(brett)
-    self.assertEqual(finder.owners_queue, [john, darin, peter, ken, tom])
+    self.assertCountEqual(finder.owners_queue, [john, darin, peter, ken, tom])
     self.assertEqual(finder.selected_owners, {brett})
     self.assertEqual(finder.deselected_owners, {ben})
     self.assertEqual(finder.reviewed_by,
@@ -220,7 +224,7 @@ class OwnersFinderTests(_BaseTestCase):
   def test_deselect(self):
     finder = self.defaultFinder()
     finder.deselect_owner(john)
-    self.assertEqual(finder.owners_queue, [brett, peter, ken, ben, tom])
+    self.assertCountEqual(finder.owners_queue, [brett, peter, ken, ben, tom])
     self.assertEqual(finder.selected_owners, {darin})
     self.assertEqual(finder.deselected_owners, {john})
     self.assertEqual(finder.reviewed_by, {'content/bar/foo.cc': darin,