Suppress "unused variable" in Ruby 2.5

activesupport/test/test_case_test.rb

@@ -87,7 +87,8 @@ def test_negative_differences
 
   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
@@ -200,7 +201,7 @@ def test_assert_changes_works_with_nil
   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
@@ -208,7 +209,7 @@ def test_assert_changes_with_to_and_case_operator
   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