Update LessThanMatcher to use MatchData

spec/matchers/less_than_matcher_spec.cr

@@ -1,22 +1,25 @@
 require "../spec_helper"
 
 describe Spectator::Matchers::LessThanMatcher do
-  describe "#match?" do
+  describe "#match" do
     it "compares using #<" do
       spy = SpySUT.new
       partial = new_partial(spy)
       matcher = Spectator::Matchers::LessThanMatcher.new(42)
-      matcher.match?(partial).should be_true
+      matcher.match(partial)
       spy.lt_call_count.should be > 0
     end
 
+    context "returned MatchData" do
+      describe "#matched?" do
         context "with a larger value" do
           it "is true" do
             actual = 42
             expected = 777
             partial = new_partial(actual)
             matcher = Spectator::Matchers::LessThanMatcher.new(expected)
-        matcher.match?(partial).should be_true
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
           end
         end
 
@@ -26,7 +29,8 @@ describe Spectator::Matchers::LessThanMatcher do
             expected = 42
             partial = new_partial(actual)
             matcher = Spectator::Matchers::LessThanMatcher.new(expected)
-        matcher.match?(partial).should be_false
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
           end
         end
 
@@ -35,7 +39,65 @@ describe Spectator::Matchers::LessThanMatcher do
             value = 42
             partial = new_partial(value)
             matcher = Spectator::Matchers::LessThanMatcher.new(value)
-        matcher.match?(partial).should be_false
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+        end
+      end
+
+      describe "#values" do
+        context "expected" do
+          it "is the expected value" do
+            actual = 42
+            expected = 777
+            partial = new_partial(actual)
+            matcher = Spectator::Matchers::LessThanMatcher.new(expected)
+            match_data = matcher.match(partial)
+            match_data.values[:expected].value.should eq(expected)
+          end
+
+          it "is prefixed with <" do
+            actual = 42
+            expected = 777
+            partial = new_partial(actual)
+            matcher = Spectator::Matchers::LessThanMatcher.new(expected)
+            match_data = matcher.match(partial)
+            match_data.values[:expected].to_s.should start_with("<")
+          end
+        end
+
+        context "actual" do
+          it "is the actual value" do
+            actual = 42
+            expected = 777
+            partial = new_partial(actual)
+            matcher = Spectator::Matchers::LessThanMatcher.new(expected)
+            match_data = matcher.match(partial)
+            match_data.values[:actual].value.should eq(actual)
+          end
+
+          context "when #matched? is true" do
+            it "is prefixed with <" do
+              actual = 42
+              expected = 777
+              partial = new_partial(actual)
+              matcher = Spectator::Matchers::LessThanMatcher.new(expected)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true # Sanity check.
+              match_data.values[:actual].to_s.should start_with("<")
+            end
+          end
+
+          context "when #matched? is false" do
+            it "is prefixed with >=" do
+              actual = 777
+              expected = 42
+              partial = new_partial(actual)
+              matcher = Spectator::Matchers::LessThanMatcher.new(expected)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false # Sanity check.
+              match_data.values[:actual].to_s.should start_with(">=")
+            end
           end
         end
       end
@@ -45,7 +107,8 @@ describe Spectator::Matchers::LessThanMatcher do
           value = 42
           partial = new_partial(value)
           matcher = Spectator::Matchers::LessThanMatcher.new(value)
-      matcher.message(partial).should contain("<")
+          match_data = matcher.match(partial)
+          match_data.message.should contain("<")
         end
 
         it "contains the actual label" do
@@ -53,7 +116,8 @@ describe Spectator::Matchers::LessThanMatcher do
           label = "everything"
           partial = new_partial(value, label)
           matcher = Spectator::Matchers::LessThanMatcher.new(value)
-      matcher.message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
         end
 
         it "contains the expected label" do
@@ -61,7 +125,8 @@ describe Spectator::Matchers::LessThanMatcher do
           label = "everything"
           partial = new_partial(value)
           matcher = Spectator::Matchers::LessThanMatcher.new(value, label)
-      matcher.message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
         end
 
         context "when expected label is omitted" do
@@ -70,7 +135,8 @@ describe Spectator::Matchers::LessThanMatcher do
             value2 = 777
             partial = new_partial(value1)
             matcher = Spectator::Matchers::LessThanMatcher.new(value2)
-        matcher.message(partial).should contain(value2.to_s)
+            match_data = matcher.match(partial)
+            match_data.message.should contain(value2.to_s)
           end
         end
       end
@@ -80,7 +146,8 @@ describe Spectator::Matchers::LessThanMatcher do
           value = 42
           partial = new_partial(value)
           matcher = Spectator::Matchers::LessThanMatcher.new(value)
-      matcher.negated_message(partial).should contain("<")
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain("<")
         end
 
         it "contains the actual label" do
@@ -88,7 +155,8 @@ describe Spectator::Matchers::LessThanMatcher do
           label = "everything"
           partial = new_partial(value, label)
           matcher = Spectator::Matchers::LessThanMatcher.new(value)
-      matcher.negated_message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain(label)
         end
 
         it "contains the expected label" do
@@ -96,7 +164,8 @@ describe Spectator::Matchers::LessThanMatcher do
           label = "everything"
           partial = new_partial(value)
           matcher = Spectator::Matchers::LessThanMatcher.new(value, label)
-      matcher.negated_message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain(label)
         end
 
         context "when expected label is omitted" do
@@ -105,7 +174,10 @@ describe Spectator::Matchers::LessThanMatcher do
             value2 = 777
             partial = new_partial(value1)
             matcher = Spectator::Matchers::LessThanMatcher.new(value2)
-        matcher.negated_message(partial).should contain(value2.to_s)
+            match_data = matcher.match(partial)
+            match_data.negated_message.should contain(value2.to_s)
+          end
+        end
       end
     end
   end

src/spectator/matchers/less_than_matcher.cr

@@ -5,27 +5,48 @@ module Spectator::Matchers
   # The values are compared with the < operator.
   struct LessThanMatcher(ExpectedType) < ValueMatcher(ExpectedType)
     # Determines whether the matcher is satisfied with the value given to it.
-    # True is returned if the match was successful, false otherwise.
-    def match?(partial)
-      partial.actual < expected
+    private def match?(actual)
+      actual < expected
     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) : MatchData
-      raise NotImplementedError.new("#match")
+    def match(partial)
+      values = ExpectedActual.new(partial, self)
+      MatchData.new(match?(values.actual), values)
+    end
+
+    # Match data specific to this matcher.
+    private struct MatchData(ExpectedType, ActualType) < MatchData
+      # Creates the match data.
+      def initialize(matched, @values : ExpectedActual(ExpectedType, ActualType))
+        super(matched)
+      end
+
+      # Information about the match.
+      def values
+        {
+          expected: PrefixedValue.new("<", @values.expected),
+          actual:   PrefixedValue.new(actual_operator, @values.actual),
+        }
+      end
+
+      # Textual operator for the actual value.
+      private def actual_operator
+        matched? ? "<" : ">="
       end
 
       # Describes the condition that satisfies the matcher.
       # This is informational and displayed to the end-user.
-    def message(partial)
-      "Expected #{partial.label} to be less than #{label} (using <)"
+      def message
+        "#{@values.actual_label} is less than #{@values.expected_label} (using <)"
       end
 
       # Describes the condition that won't satsify the matcher.
       # This is informational and displayed to the end-user.
-    def negated_message(partial)
-      "Expected #{partial.label} to not be less than #{label} (using <)"
+      def negated_message
+        "#{@values.actual_label} is greater than or equal to #{@values.expected_label} (using <)"
+      end
     end
   end
 end