ExpectationFailed exception takes a result

src/spectator/expectation_failed.cr

@@ -1,4 +1,14 @@
 module Spectator
+  # Exception that indicates a required expectation was not met in an example.
   class ExpectationFailed < Exception
+    # Outcome of the expectation.
+    # Additional information can be retrieved through this.
+    getter result : Expectations::Expectation::Result
+
+    # Creates the exception.
+    # The exception string is generated from the expecation message.
+    def initialize(@result)
+      super(@result.actual_message)
+    end
   end
 end