Fix ContentResultAssertions messages.

Author: faddiv

src/FluentAssertions.AspNetCore.Mvc/ContentResultAssertions.cs

@@ -35,7 +35,8 @@ public ContentResultAssertions WithContent(string expectedContent, string reason
             Execute.Assertion
                    .ForCondition(string.Equals(actualContent, expectedContent, StringComparison.OrdinalIgnoreCase))
                    .BecauseOf(reason, reasonArgs)
-                   .FailWith(string.Format(FailureMessages.CommonFailMessage, "ContentResult.Content", expectedContent, actualContent));
+                   .WithDefaultIdentifier("ContentResult.Content")
+                   .FailWith(FailureMessages.CommonFailMessage2, expectedContent, actualContent);
 
             return this;
         }
@@ -58,7 +59,8 @@ public ContentResultAssertions WithContentType(string expectedContentType, strin
             Execute.Assertion
                    .ForCondition(string.Equals(expectedContentType, actualContentType, StringComparison.OrdinalIgnoreCase))
                    .BecauseOf(reason, reasonArgs)
-                   .FailWith(string.Format(FailureMessages.CommonFailMessage, "ContentResult.ContentType", expectedContentType, actualContentType));
+                   .WithDefaultIdentifier("ContentResult.ContentType")
+                   .FailWith(FailureMessages.CommonFailMessage2, expectedContentType, actualContentType);
 
             return this;
         }

src/FluentAssertions.AspNetCore.Mvc/FailureMessages.Designer.cs

@@ -120,6 +120,9 @@
   <data name="CommonFailMessage" xml:space="preserve">
     <value>Expected {0} to be '{1}' but found '{2}'</value>
   </data>
+  <data name="CommonFailMessage2" xml:space="preserve">
+    <value>Expected {context} to be {0}{reason} but found {1}.</value>
+  </data>
   <data name="CommonNullWasSuppliedFailMessage" xml:space="preserve">
     <value>Expected {0} to be of type {1}, but no {0} was supplied.</value>
   </data>

src/FluentAssertions.AspNetCore.Mvc/FailureMessages.resx

@@ -20,9 +20,9 @@ public void WithContent_GivenUnexpected_ShouldFail()
             var actualContent = "content";
             var expectedContent = "xyz";
             ActionResult result = new ContentResult { Content = actualContent };
-            var failureMessage = String.Format(FailureMessages.CommonFailMessage, "ContentResult.Content", expectedContent, actualContent);
+            var failureMessage = ExpectedFailureMessage("ContentResult.Content", expectedContent, actualContent);
 
-            Action a = () => result.Should().BeContentResult().WithContent(expectedContent);
+            Action a = () => result.Should().BeContentResult().WithContent(expectedContent, "it is {0}", 10);
 
             a.Should().Throw<Exception>()
                 .WithMessage(failureMessage);
@@ -41,12 +41,18 @@ public void WithContentType_GivenUnexpected_ShouldFail()
             var actualContentType = "text/html";
             var expectedContentType = "xyz";
             ActionResult result = new ContentResult { ContentType = actualContentType };
-            var failureMessage = String.Format(FailureMessages.CommonFailMessage, "ContentResult.ContentType", expectedContentType, actualContentType);
+            var failureMessage = ExpectedFailureMessage("ContentResult.ContentType", expectedContentType, actualContentType);
 
-            Action a = () => result.Should().BeContentResult().WithContentType(expectedContentType);
+            Action a = () => result.Should().BeContentResult().WithContentType(expectedContentType, "it is {0}", 10);
 
             a.Should().Throw<Exception>()
                 .WithMessage(failureMessage);
         }
+
+        private string ExpectedFailureMessage(string context, string expected, string actual)
+        {
+            return $"Expected {context} to be \"{expected}\" because it is 10 but found \"{actual}\".";
+        }
+
     }
 }