Update HaveKeyMatcher to use MatchData

spec/matchers/have_key_matcher_spec.cr

@@ -1,7 +1,15 @@
 require "../spec_helper"
 
+private struct FakeKeySet
+  def has_key?(key)
+    true
+  end
+end
+
 describe Spectator::Matchers::HaveKeyMatcher do
-  describe "#match?" do
+  describe "#match" do
+    context "returned MatchData" do
+      describe "#matched?" do
         context "against a Hash" do
           context "with an existing key" do
             it "is true" do
@@ -9,7 +17,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
               key = "foo"
               partial = new_partial(hash)
               matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -19,7 +28,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
               key = "baz"
               partial = new_partial(hash)
               matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
         end
@@ -31,7 +41,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
               key = :foo
               partial = new_partial(tuple)
               matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -41,7 +52,45 @@ describe Spectator::Matchers::HaveKeyMatcher do
               key = :baz
               partial = new_partial(tuple)
               matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+          end
+        end
+      end
+
+      describe "#values" do
+        context "key" do
+          it "is the expected key" do
+            tuple = {foo: "bar"}
+            key = :baz
+            partial = new_partial(tuple)
+            matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
+            match_data = matcher.match(partial)
+            match_data.values[:key].should eq(key)
+          end
+        end
+
+        context "actual" do
+          context "when #keys is available" do
+            it "is the list of keys" do
+              tuple = {foo: "bar"}
+              key = :baz
+              partial = new_partial(tuple)
+              matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
+              match_data = matcher.match(partial)
+              match_data.values[:actual].should eq(tuple.keys)
+            end
+          end
+
+          context "when #keys isn't available" do
+            it "is the actual value" do
+              actual = FakeKeySet.new
+              key = :baz
+              partial = new_partial(actual)
+              matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
+              match_data = matcher.match(partial)
+              match_data.values[:actual].should eq(actual)
             end
           end
         end
@@ -54,7 +103,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
           label = "blah"
           partial = new_partial(tuple, label)
           matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-      matcher.message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
         end
 
         it "contains the expected label" do
@@ -63,7 +113,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
           label = "blah"
           partial = new_partial(tuple)
           matcher = Spectator::Matchers::HaveKeyMatcher.new(key, label)
-      matcher.message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
         end
 
         context "when the expected label is omitted" do
@@ -72,7 +123,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
             key = :foo
             partial = new_partial(tuple)
             matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-        matcher.message(partial).should contain(key.to_s)
+            match_data = matcher.match(partial)
+            match_data.message.should contain(key.to_s)
           end
         end
       end
@@ -84,7 +136,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
           label = "blah"
           partial = new_partial(tuple, label)
           matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-      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
@@ -93,7 +146,8 @@ describe Spectator::Matchers::HaveKeyMatcher do
           label = "blah"
           partial = new_partial(tuple)
           matcher = Spectator::Matchers::HaveKeyMatcher.new(key, label)
-      matcher.negated_message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain(label)
         end
 
         context "when the expected label is omitted" do
@@ -102,7 +156,10 @@ describe Spectator::Matchers::HaveKeyMatcher do
             key = :foo
             partial = new_partial(tuple)
             matcher = Spectator::Matchers::HaveKeyMatcher.new(key)
-        matcher.negated_message(partial).should contain(key.to_s)
+            match_data = matcher.match(partial)
+            match_data.negated_message.should contain(key.to_s)
+          end
+        end
       end
     end
   end

src/spectator/matchers/have_key_matcher.cr

@@ -5,27 +5,44 @@ module Spectator::Matchers
   # The set is checked with the `has_key?` method.
   struct HaveKeyMatcher(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.
+    private def match?(actual)
-    def match?(partial)
+      actual.has_key?(expected)
-      partial.actual.has_key?(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
+    def match(partial)
-      raise NotImplementedError.new("#match")
+      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
+        actual = @values.actual
+        {
+          key:    @values.expected,
+          actual: actual.responds_to?(:keys) ? actual.keys : actual,
+        }
       end
 
       # Describes the condition that satisfies the matcher.
       # This is informational and displayed to the end-user.
-    def message(partial)
+      def message
-      "Expected #{partial.label} to have key #{label}"
+        "#{@values.actual_label} has key #{@values.expected_label}"
       end
 
       # Describes the condition that won't satsify the matcher.
       # This is informational and displayed to the end-user.
-    def negated_message(partial)
+      def negated_message
-      "Expected #{partial.label} to not have key #{label}"
+        "#{@values.actual_label} does not have key #{@values.expected_label}"
+      end
     end
   end
 end