1 files changed, 8 insertions, 7 deletions
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index af7fc44d66..84e4953fe2 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "abstract_unit"
 
 class AssertDifferenceTest < ActiveSupport::TestCase
@@ -85,7 +87,8 @@ class AssertDifferenceTest < ActiveSupport::TestCase
 
   def test_expression_is_evaluated_in_the_appropriate_scope
     silence_warnings do
-      local_scope = local_scope = "foo"
+      local_scope = "foo"
+      local_scope = local_scope  # to suppress unused variable warning
       assert_difference("local_scope; @object.num") { @object.increment }
     end
   end
@@ -176,6 +179,7 @@ class AssertDifferenceTest < ActiveSupport::TestCase
   end
 
   def test_assert_changes_works_with_any_object
+    # Silences: instance variable @new_object not initialized.
     retval = silence_warnings do
       assert_changes :@new_object, from: nil, to: 42 do
         @new_object = 42
@@ -198,7 +202,7 @@ class AssertDifferenceTest < ActiveSupport::TestCase
   def test_assert_changes_with_to_and_case_operator
     token = nil
 
-    assert_changes "token", to: /\w{32}/ do
+    assert_changes -> { token }, to: /\w{32}/ do
       token = SecureRandom.hex
     end
   end
@@ -206,7 +210,7 @@ class AssertDifferenceTest < ActiveSupport::TestCase
   def test_assert_changes_with_to_and_from_and_case_operator
     token = SecureRandom.hex
 
-    assert_changes "token", from: /\w{32}/, to: /\w{32}/ do
+    assert_changes -> { token }, from: /\w{32}/, to: /\w{32}/ do
       token = SecureRandom.hex
     end
   end
@@ -233,13 +237,10 @@ class AssertDifferenceTest < ActiveSupport::TestCase
       end
     end
 
-    assert_equal "@object.num should not change.\n\"@object.num\" did change to 1.\nExpected: 0\n  Actual: 1", error.message
+    assert_equal "@object.num should not change.\n\"@object.num\" did change to 1", error.message
   end
 end
 
-class AlsoDoingNothingTest < ActiveSupport::TestCase
-end
-
 # Setup and teardown callbacks.
 class SetupAndTeardownTest < ActiveSupport::TestCase
   setup :reset_callback_record, :foo