diff --git a/activesupport/lib/active_support/testing/assertions.rb b/activesupport/lib/active_support/testing/assertions.rb
index 6a6941c72a16ae9006ab945c774405045fa1e454..8c9ea2c0e8b0b1806933e8c109f4ea52dd5f451a 100644
--- a/activesupport/lib/active_support/testing/assertions.rb
+++ b/activesupport/lib/active_support/testing/assertions.rb
@@ -147,7 +147,7 @@ def assert_changes(expression, message = nil, from: UNTRACKED, to: UNTRACKED, &b
         retval = yield
 
         unless from == UNTRACKED
-          error = "#{expression.inspect} isn't #{from}"
+          error = "#{expression.inspect} isn't #{from.inspect}"
           error = "#{message}.\n#{error}" if message
           assert from === before, error
         end
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index d3d2ed8d7ae6cd409d0bbf756071e5f0059f40c5..dfbb8aa41d08f3fd0fc9913c178221ec22e3b0bf 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -138,6 +138,15 @@ def test_assert_changes_with_from_option_with_wrong_value
     end
   end
 
+  def test_assert_changes_with_from_option_with_nil
+    error = assert_raises Minitest::Assertion do
+      assert_changes "@object.num", from: nil do
+        @object.increment
+      end
+    end
+    assert_equal "\"@object.num\" isn't nil", error.message
+  end
+
   def test_assert_changes_with_to_option
     assert_changes "@object.num", to: 1 do
       @object.increment