Display last item and full list when #last is used

Only perform one check with #responds_to?.

src/spectator/matchers/end_with_matcher.cr

@@ -6,23 +6,31 @@ module Spectator::Matchers
   # Otherwise, it is treated as an `Indexable` and the `last` value is compared against.
   struct EndWithMatcher(ExpectedType) < ValueMatcher(ExpectedType)
     # Determines whether the matcher is satisfied with the value given to it.
-    private def match?(actual)
-      if actual.responds_to?(:ends_with?)
+    private def match_ends_with?(actual)
       actual.ends_with?(expected)
-      else
-        expected === actual.last
     end
+
+    # Determines whether the matcher is satisfied with the value given to it.
+    private def match_last?(actual)
+      expected === actual
     end
 
     # Determines whether the matcher is satisfied with the partial given to it.
     # `MatchData` is returned that contains information about the match.
     def match(partial)
       values = ExpectedActual.new(partial, self)
-      MatchData.new(match?(values.actual), values)
+      actual = values.actual
+      if actual.responds_to?(:ends_with?)
+        EndsWithMatchData.new(match_ends_with?(actual), values)
+      else
+        last = actual.last
+        LastMatchData.new(match_last?(last), values, last)
+      end
     end
 
     # Match data specific to this matcher.
-    private struct MatchData(ExpectedType, ActualType) < MatchData
+    # This type is used when the actual value responds to `ends_with?`.
+    private struct EndsWithMatchData(ExpectedType, ActualType) < MatchData
       # Creates the match data.
       def initialize(matched, @values : ExpectedActual(ExpectedType, ActualType))
         super(matched)
@@ -39,21 +47,43 @@ module Spectator::Matchers
       # Describes the condition that satisfies the matcher.
       # This is informational and displayed to the end-user.
       def message
-        "#{@values.actual_label} ends with #{@values.expected_label} (using #{comparison_method})"
+        "#{@values.actual_label} ends with #{@values.expected_label} (using #ends_with?)"
       end
 
       # Describes the condition that won't satsify the matcher.
       # This is informational and displayed to the end-user.
       def negated_message
-        "#{@values.actual_label} does not end with #{@values.expected_label} (using #{comparison_method})"
+        "#{@values.actual_label} does not end with #{@values.expected_label} (using #ends_with?)"
+      end
     end
 
-      private def comparison_method
-        if @values.actual.responds_to?(:ends_with?)
-          "#ends_with?"
-        else
-          "expected === actual.last"
-        end
+    # Match data specific to this matcher.
+    # This type is used when the actual value does not respond to `ends_with?`.
+    private struct LastMatchData(ExpectedType, ActualType, LastType) < MatchData
+      # Creates the match data.
+      def initialize(matched, @values : ExpectedActual(ExpectedType, ActualType), @last : LastType)
+        super(matched)
+      end
+
+      # Information about the match.
+      def values
+        {
+          expected: @values.expected,
+          actual:   @last,
+          list:     @values.actual,
+        }
+      end
+
+      # Describes the condition that satisfies the matcher.
+      # This is informational and displayed to the end-user.
+      def message
+        "#{@values.actual_label} ends with #{@values.expected_label} (using expected === actual.last)"
+      end
+
+      # Describes the condition that won't satsify the matcher.
+      # This is informational and displayed to the end-user.
+      def negated_message
+        "#{@values.actual_label} does not end with #{@values.expected_label} (using expected === actual.last)"
       end
     end
   end