Add missing methods to matchers

Fix matcher inheritance.

src/spectator/matchers/exception_matcher.cr

@@ -15,6 +15,14 @@ module Spectator::Matchers
     def initialize(@expected : TestValue(ExpectedType))
     end
 
+    def description
+      if (message = @expected)
+        "raises #{ExceptionType} with message #{message}"
+      else
+        "raises #{ExceptionType}"
+      end
+    end
+
     def match(actual)
       exception = capture_exception { actual.value }
       case exception

src/spectator/matchers/have_predicate_matcher.cr

@@ -34,6 +34,14 @@ module Spectator::Matchers
       end
     end
 
+    private def failure_message(actual)
+      "#{actual.label} does not have #{expected.label}"
+    end
+
+    private def failure_message_when_negated(actual)
+      "#{actual.label} has #{expected.label}"
+    end
+
     # Captures all of the actual values.
     # A `NamedTuple` is returned, with each key being the attribute.
     private def snapshot_values(object)

src/spectator/matchers/predicate_matcher.cr

@@ -5,7 +5,7 @@ module Spectator::Matchers
   # The `ExpectedType` type param should be a `NamedTuple`.
   # Each key in the tuple is a predicate (without the '?') to test.
   # Each value is a a `Tuple` of arguments to pass to the predicate method.
-  struct PredicateMatcher(ExpectedType) < Matcher(ExpectedType)
+  struct PredicateMatcher(ExpectedType) < Matcher
     private getter expected
 
     def initialize(@expected : TestValue(ExpectedType))
@@ -33,6 +33,14 @@ module Spectator::Matchers
       end
     end
 
+    private def failure_message(actual)
+      "#{actual.label} is not #{expected.label}"
+    end
+
+    private def failure_message_when_negated(actual)
+      "#{actual.label} is #{expected.label}"
+    end
+
     # Captures all of the actual values.
     # A `NamedTuple` is returned, with each key being the attribute.
     private def snapshot_values(object)