Update AttributesMatcher to use MatchData

This is a glorious mess.

spec/matchers/attributes_matcher_spec.cr

@@ -1,16 +1,18 @@
 require "../spec_helper"
 
 describe Spectator::Matchers::AttributesMatcher do
-  describe "#match?" do
+  describe "#match" do
     it "uses ===" do
       array = %i[a b c]
       spy = SpySUT.new
       partial = new_partial(array)
-      matcher = Spectator::Matchers::HaveMatcher.new({spy})
-      matcher.match?(partial).should be_true
+      matcher = Spectator::Matchers::AttributesMatcher.new({first: spy})
+      matcher.match(partial)
       spy.case_eq_call_count.should be > 0
     end
 
+    context "returned MatchData" do
+      describe "#matched?" do
         context "one argument" do
           context "against an equal value" do
             it "is true" do
@@ -18,7 +20,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: :a}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -28,7 +31,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: :z}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -38,7 +42,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Symbol}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -48,7 +53,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Int32}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -58,7 +64,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: /foo/i}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -68,7 +75,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: /qux/i}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
         end
@@ -80,7 +88,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: :a, last: :c}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
 
             context "matching type" do
@@ -90,7 +99,8 @@ describe Spectator::Matchers::AttributesMatcher do
                   attributes = {first: Symbol, last: /foo/i}
                   partial = new_partial(array)
                   matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-              matcher.match?(partial).should be_true
+                  match_data = matcher.match(partial)
+                  match_data.matched?.should be_true
                 end
               end
 
@@ -100,7 +110,8 @@ describe Spectator::Matchers::AttributesMatcher do
                   attributes = {first: Symbol, last: /bar/i}
                   partial = new_partial(array)
                   matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-              matcher.match?(partial).should be_false
+                  match_data = matcher.match(partial)
+                  match_data.matched?.should be_false
                 end
               end
             end
@@ -112,7 +123,8 @@ describe Spectator::Matchers::AttributesMatcher do
                   attributes = {first: Float32, last: /foo/i}
                   partial = new_partial(array)
                   matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-              matcher.match?(partial).should be_false
+                  match_data = matcher.match(partial)
+                  match_data.matched?.should be_false
                 end
               end
 
@@ -122,7 +134,8 @@ describe Spectator::Matchers::AttributesMatcher do
                   attributes = {first: Float32, last: /bar/i}
                   partial = new_partial(array)
                   matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-              matcher.match?(partial).should be_false
+                  match_data = matcher.match(partial)
+                  match_data.matched?.should be_false
                 end
               end
             end
@@ -134,7 +147,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: :a, last: :d}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -144,7 +158,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: :d, last: :e}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -154,7 +169,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Symbol, last: String}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -164,7 +180,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Symbol, last: Float32}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -174,7 +191,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Float32, last: Bytes}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -184,7 +202,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: /foo/i, last: /baz/i}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
 
@@ -194,7 +213,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: /foo/i, last: /qux/i}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -204,7 +224,8 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: /baz/i, last: /qux/i}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_false
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
             end
           end
 
@@ -214,12 +235,63 @@ describe Spectator::Matchers::AttributesMatcher do
               attributes = {first: Symbol, last: /foo/i, size: 3}
               partial = new_partial(array)
               matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-          matcher.match?(partial).should be_true
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
             end
           end
         end
       end
 
+      describe "#values" do
+        it "contains a key for each expected attribute" do
+          array = [:a, 42, "FOO"]
+          attributes = {first: Symbol, last: /foo/i, size: 3}
+          partial = new_partial(array)
+          matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
+          match_data = matcher.match(partial)
+          values = match_data.values
+          values.has_key?(:"expected first").should be_true
+          values.has_key?(:"expected last").should be_true
+          values.has_key?(:"expected size").should be_true
+        end
+
+        it "contains a key for each actual value" do
+          array = [:a, 42, "FOO"]
+          attributes = {first: Symbol, last: /foo/i, size: 3}
+          partial = new_partial(array)
+          matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
+          match_data = matcher.match(partial)
+          values = match_data.values
+          values.has_key?(:"actual first").should be_true
+          values.has_key?(:"actual last").should be_true
+          values.has_key?(:"actual size").should be_true
+        end
+
+        it "has the expected values" do
+          array = [:a, 42, "FOO"]
+          attributes = {first: Symbol, last: /foo/i, size: 3}
+          partial = new_partial(array)
+          matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
+          match_data = matcher.match(partial)
+          values = match_data.values
+          values[:"expected first"].should eq(attributes[:first])
+          values[:"expected last"].should eq(attributes[:last])
+          values[:"expected size"].should eq(attributes[:size])
+        end
+
+        it "has the actual values" do
+          array = [:a, 42, "FOO"]
+          attributes = {first: Symbol, last: /foo/i, size: 3}
+          partial = new_partial(array)
+          matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
+          match_data = matcher.match(partial)
+          values = match_data.values
+          values[:"actual first"].should eq(array.first)
+          values[:"actual last"].should eq(array.last)
+          values[:"actual size"].should eq(array.size)
+        end
+      end
+
       describe "#message" do
         it "contains the actual label" do
           value = "foobar"
@@ -227,7 +299,8 @@ describe Spectator::Matchers::AttributesMatcher do
           label = "everything"
           partial = new_partial(value, label)
           matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-      matcher.message(partial).should contain(label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
         end
 
         it "contains the expected label" do
@@ -236,7 +309,8 @@ describe Spectator::Matchers::AttributesMatcher do
           label = "everything"
           partial = new_partial(value)
           matcher = Spectator::Matchers::AttributesMatcher.new(attributes, 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
@@ -245,7 +319,8 @@ describe Spectator::Matchers::AttributesMatcher do
             attributes = {size: 6}
             partial = new_partial(value)
             matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-        matcher.message(partial).should contain(attributes.to_s)
+            match_data = matcher.match(partial)
+            match_data.message.should contain(attributes.to_s)
           end
         end
       end
@@ -257,7 +332,8 @@ describe Spectator::Matchers::AttributesMatcher do
           label = "everything"
           partial = new_partial(value, label)
           matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-      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
@@ -266,7 +342,8 @@ describe Spectator::Matchers::AttributesMatcher do
           label = "everything"
           partial = new_partial(value)
           matcher = Spectator::Matchers::AttributesMatcher.new(attributes, 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
@@ -275,7 +352,10 @@ describe Spectator::Matchers::AttributesMatcher do
             attributes = {size: 6}
             partial = new_partial(value)
             matcher = Spectator::Matchers::AttributesMatcher.new(attributes)
-        matcher.negated_message(partial).should contain(attributes.to_s)
+            match_data = matcher.match(partial)
+            match_data.negated_message.should contain(attributes.to_s)
+          end
+        end
       end
     end
   end

src/spectator/matchers/attributes_matcher.cr

@@ -6,13 +6,10 @@ module Spectator::Matchers
   # The `ExpectedType` type param should be a `NamedTuple`.
   struct AttributesMatcher(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)
-      actual = partial.actual
-
+    private def match?(actual)
       # Test each attribute and immediately return false if a comparison fails.
       {% for attribute in ExpectedType.keys %}
-      return false unless expected[{{attribute.symbolize}}] === actual.{{attribute}}
+      return false unless expected[{{attribute.symbolize}}] === actual[{{attribute.symbolize}}]
       {% end %}
 
       # All checks passed if this point is reached.
@@ -21,20 +18,55 @@ module Spectator::Matchers
 
     # 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)
+      actual_values = snapshot_values(partial.actual)
+      values = ExpectedActual.new(expected, label, actual_values, partial.label)
+      MatchData.new(match?(actual_values), values)
+    end
+
+    # Captures all of the actual values.
+    # A `NamedTuple` is returned,
+    # with each key being the attribute.
+    private def snapshot_values(actual)
+      {% begin %}
+      {
+        {% for attribute in ExpectedType.keys %}
+        {{attribute}}: actual.{{attribute}},
+        {% end %}
+      }
+      {% end %}
+    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
+        {% begin %}
+        {
+          {% for attribute in ExpectedType.keys %}
+          {{"expected " + attribute.stringify}}: @values.expected[{{attribute.symbolize}}],
+          {{"actual " + attribute.stringify}}:   @values.actual[{{attribute.symbolize}}],
+          {% end %}
+        }
+        {% end %}
       end
 
       # Describes the condition that satisfies the matcher.
       # This is informational and displayed to the end-user.
-    def message(partial)
-      "Expected #{partial.label} to have #{label}"
+      def message
+        "#{@values.actual_label} has attributes #{@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)
-      "Expected #{partial.label} to not have #{label}"
+      def negated_message
+        "#{@values.actual_label} does not have attributes #{@values.expected_label}"
+      end
     end
   end
 end