Merge pull request #31011 from danielma/dma/assert-changes-with-to-should-still-assert-change

`assert_changes` should always assert some change

1 files changed, 11 insertions, 0 deletions

diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index 84e4953fe2..79b75a001a 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -156,6 +156,16 @@ class AssertDifferenceTest < ActiveSupport::TestCase
     end
   end
 
+  def test_assert_changes_with_to_option_but_no_change_has_special_message
+    error = assert_raises Minitest::Assertion do
+      assert_changes "@object.num", to: 0 do
+        # no changes
+      end
+    end
+
+    assert_equal "\"@object.num\" didn't change. It was already 0", error.message
+  end
+
   def test_assert_changes_with_wrong_to_option
     assert_raises Minitest::Assertion do
       assert_changes "@object.num", to: 2 do
@@ -218,6 +228,7 @@ class AssertDifferenceTest < ActiveSupport::TestCase
   def test_assert_changes_with_message
     error = assert_raises Minitest::Assertion do
       assert_changes "@object.num", "@object.num should 1", to: 1 do
+        @object.decrement
       end
     end