1 files changed, 46 insertions, 4 deletions
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index 8830c9b348..eced622137 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -87,7 +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
@@ -114,6 +115,35 @@ class AssertDifferenceTest < ActiveSupport::TestCase
     end
   end
 
+  def test_hash_of_expressions
+    assert_difference "@object.num" => 1, "@object.num + 1" => 1 do
+      @object.increment
+    end
+  end
+
+  def test_hash_of_expressions_with_message
+    error = assert_raises Minitest::Assertion do
+      assert_difference({ "@object.num" => 0 }, "Object Changed") do
+        @object.increment
+      end
+    end
+    assert_equal "Object Changed.\n\"@object.num\" didn't change by 0.\nExpected: 0\n  Actual: 1", error.message
+  end
+
+  def test_hash_of_lambda_expressions
+    assert_difference -> { @object.num } => 1, -> { @object.num + 1 } => 1 do
+      @object.increment
+    end
+  end
+
+  def test_hash_of_expressions_identify_failure
+    assert_raises(Minitest::Assertion) do
+      assert_difference "@object.num" => 1, "1 + 1" => 1 do
+        @object.increment
+      end
+    end
+  end
+
   def test_assert_changes_pass
     assert_changes "@object.num" do
       @object.increment
@@ -155,6 +185,16 @@ 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
@@ -178,6 +218,7 @@ 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
@@ -200,7 +241,7 @@ 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
@@ -208,7 +249,7 @@ 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
@@ -216,6 +257,7 @@ 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
 
@@ -235,7 +277,7 @@ 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