From 77307f6eb1554cbead2bec8948a6a2d73e5d0f1d Mon Sep 17 00:00:00 2001
From: Michael Miller <icy.arctic.fox@gmail.com>
Date: Thu, 16 May 2019 18:20:08 -0600
Subject: [PATCH] Split part of RangeMatcher off as CollectionMatcher

Use CollectionMatcher for `be_within`.
The `#of` method creates a RangeMatcher.
---
 spec/matchers/collection_matcher_spec.cr     | 391 ++++++++++++++++
 spec/matchers/range_matcher_spec.cr          | 468 ++++++-------------
 src/spectator/dsl/matcher_dsl.cr             |   4 +-
 src/spectator/matchers/collection_matcher.cr |  67 +++
 src/spectator/matchers/range_matcher.cr      |  63 +--
 5 files changed, 609 insertions(+), 384 deletions(-)
 create mode 100644 spec/matchers/collection_matcher_spec.cr
 create mode 100644 src/spectator/matchers/collection_matcher.cr

diff --git a/spec/matchers/collection_matcher_spec.cr b/spec/matchers/collection_matcher_spec.cr
new file mode 100644
index 0000000..f848792
--- /dev/null
+++ b/spec/matchers/collection_matcher_spec.cr
@@ -0,0 +1,391 @@
+require "../spec_helper"
+
+describe Spectator::Matchers::CollectionMatcher do
+  describe "#match" do
+    it "compares using #includes?" do
+      spy = SpySUT.new
+      partial = new_partial(5)
+      matcher = Spectator::Matchers::CollectionMatcher.new(spy)
+      matcher.match(partial)
+      spy.includes_call_count.should be > 0
+    end
+
+    context "returned MatchData" do
+      describe "#matched?" do
+        context "given a Range" do
+          context "inclusive" do
+            it "is true for lower-bound" do
+              lower = 3
+              upper = 9
+              value = lower
+              range = Range.new(lower, upper, exclusive: false)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
+            end
+
+            it "is false for lower-bound minus 1" do
+              lower = 3
+              upper = 9
+              value = lower - 1
+              range = Range.new(lower, upper, exclusive: false)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+
+            it "is true for mid-range" do
+              lower = 3
+              upper = 9
+              value = 5
+              range = Range.new(lower, upper, exclusive: false)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
+            end
+
+            it "is true for upper-bound" do
+              lower = 3
+              upper = 9
+              value = upper
+              range = Range.new(lower, upper, exclusive: false)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
+            end
+
+            it "is false for upper-bound plus 1" do
+              lower = 3
+              upper = 9
+              value = upper + 1
+              range = Range.new(lower, upper, exclusive: false)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+          end
+
+          context "exclusive" do
+            it "is true for lower-bound" do
+              lower = 3
+              upper = 9
+              value = lower
+              range = Range.new(lower, upper, exclusive: true)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
+            end
+
+            it "is false for lower-bound minus 1" do
+              lower = 3
+              upper = 9
+              value = lower - 1
+              range = Range.new(lower, upper, exclusive: true)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+
+            it "is true for mid-range" do
+              lower = 3
+              upper = 9
+              value = 5
+              range = Range.new(lower, upper, exclusive: true)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_true
+            end
+
+            it "is false for upper-bound" do
+              lower = 3
+              upper = 9
+              value = upper
+              range = Range.new(lower, upper, exclusive: true)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+
+            it "is false for upper-bound plus 1" do
+              lower = 3
+              upper = 9
+              value = upper + 1
+              range = Range.new(lower, upper, exclusive: true)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data.matched?.should be_false
+            end
+          end
+        end
+
+        context "given an Enumerable" do
+          it "is true for an existing item" do
+            array = %i[a b c]
+            value = :b
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::CollectionMatcher.new(array)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
+          end
+
+          it "is false for a non-existing item" do
+            array = %i[a b c]
+            value = :z
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::CollectionMatcher.new(array)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+        end
+      end
+
+      describe "#values" do
+        context "given a Range" do
+          context "collection" do
+            it "is the expected value" do
+              value = 5
+              range = Range.new(3, 9)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data_value_sans_prefix(match_data.values, :collection)[:value].should eq(range)
+            end
+          end
+
+          context "actual" do
+            it "is the actual value" do
+              value = 5
+              range = Range.new(3, 9)
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(range)
+              match_data = matcher.match(partial)
+              match_data_value_sans_prefix(match_data.values, :actual)[:value].should eq(value)
+            end
+          end
+        end
+
+        context "given an Enumerable" do
+          context "collection" do
+            it "is the expected value" do
+              array = %i[a b c]
+              value = :z
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(array)
+              match_data = matcher.match(partial)
+              match_data_value_sans_prefix(match_data.values, :collection)[:value].should eq(array)
+            end
+          end
+
+          context "actual" do
+            it "is the actual value" do
+              array = %i[a b c]
+              value = :z
+              partial = new_partial(value)
+              matcher = Spectator::Matchers::CollectionMatcher.new(array)
+              match_data = matcher.match(partial)
+              match_data_value_sans_prefix(match_data.values, :actual)[:value].should eq(value)
+            end
+          end
+        end
+      end
+
+      describe "#message" do
+        it "contains the actual label" do
+          range = 1..10
+          value = 5
+          label = "everything"
+          partial = new_partial(value, label)
+          matcher = Spectator::Matchers::CollectionMatcher.new(range)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
+        end
+
+        it "contains the expected label" do
+          range = 1..10
+          value = 5
+          label = "everything"
+          partial = new_partial(value)
+          matcher = Spectator::Matchers::CollectionMatcher.new(range, label)
+          match_data = matcher.match(partial)
+          match_data.message.should contain(label)
+        end
+
+        context "when expected label is omitted" do
+          it "contains stringified form of expected value" do
+            range = 1..10
+            value = 5
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::CollectionMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.message.should contain(range.to_s)
+          end
+        end
+      end
+
+      describe "#negated_message" do
+        it "contains the actual label" do
+          range = 1..10
+          value = 5
+          label = "everything"
+          partial = new_partial(value, label)
+          matcher = Spectator::Matchers::CollectionMatcher.new(range)
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain(label)
+        end
+
+        it "contains the expected label" do
+          range = 1..10
+          value = 5
+          label = "everything"
+          partial = new_partial(value)
+          matcher = Spectator::Matchers::CollectionMatcher.new(range, label)
+          match_data = matcher.match(partial)
+          match_data.negated_message.should contain(label)
+        end
+
+        context "when expected label is omitted" do
+          it "contains stringified form of expected value" do
+            range = 1..10
+            value = 5
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::CollectionMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.negated_message.should contain(range.to_s)
+          end
+        end
+      end
+    end
+  end
+
+  describe "#of" do
+    it "is true for lower-bound" do
+      center = 5
+      diff = 4
+      lower = center - diff
+      value = lower
+      partial = new_partial(value)
+      matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+      match_data = matcher.match(partial)
+      match_data.matched?.should be_true
+    end
+
+    it "is false for lower-bound minus 1" do
+      center = 5
+      diff = 4
+      lower = center - diff
+      value = lower - 1
+      partial = new_partial(value)
+      matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+      match_data = matcher.match(partial)
+      match_data.matched?.should be_false
+    end
+
+    it "is true for mid-range" do
+      center = 5
+      diff = 4
+      value = center
+      partial = new_partial(value)
+      matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+      match_data = matcher.match(partial)
+      match_data.matched?.should be_true
+    end
+
+    it "is true for upper-bound" do
+      center = 5
+      diff = 4
+      upper = center + diff
+      value = upper
+      partial = new_partial(value)
+      matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+      match_data = matcher.match(partial)
+      match_data.matched?.should be_true
+    end
+
+    it "is false for upper-bound plus 1" do
+      center = 5
+      diff = 4
+      upper = center + diff
+      value = upper + 1
+      partial = new_partial(value)
+      matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+      match_data = matcher.match(partial)
+      match_data.matched?.should be_false
+    end
+
+    describe "#message" do
+      it "contains the original label" do
+        center = 5
+        diff = 4
+        value = 3
+        label = "foobar"
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff, label).of(center)
+        match_data = matcher.match(partial)
+        match_data.message.should contain(label)
+      end
+
+      it "contains the center" do
+        center = 5
+        diff = 4
+        value = 3
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+        match_data = matcher.match(partial)
+        match_data.message.should contain(center.to_s)
+      end
+
+      it "contains the diff" do
+        center = 5
+        diff = 4
+        value = 3
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+        match_data = matcher.match(partial)
+        match_data.message.should contain(diff.to_s)
+      end
+    end
+
+    describe "#negated_message" do
+      it "contains the original label" do
+        center = 5
+        diff = 4
+        value = 3
+        label = "foobar"
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff, label).of(center)
+        match_data = matcher.match(partial)
+        match_data.negated_message.should contain(label)
+      end
+
+      it "contains the center" do
+        center = 5
+        diff = 4
+        value = 3
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+        match_data = matcher.match(partial)
+        match_data.negated_message.should contain(center.to_s)
+      end
+
+      it "contains the diff" do
+        center = 5
+        diff = 4
+        value = 3
+        partial = new_partial(value)
+        matcher = Spectator::Matchers::CollectionMatcher.new(diff).of(center)
+        match_data = matcher.match(partial)
+        match_data.negated_message.should contain(diff.to_s)
+      end
+    end
+  end
+end
diff --git a/spec/matchers/range_matcher_spec.cr b/spec/matchers/range_matcher_spec.cr
index 71ffa15..5f473a5 100644
--- a/spec/matchers/range_matcher_spec.cr
+++ b/spec/matchers/range_matcher_spec.cr
@@ -2,147 +2,117 @@ require "../spec_helper"
 
 describe Spectator::Matchers::RangeMatcher do
   describe "#match" do
-    it "compares using #includes?" do
-      spy = SpySUT.new
-      partial = new_partial(5)
-      matcher = Spectator::Matchers::RangeMatcher.new(spy)
-      matcher.match(partial)
-      spy.includes_call_count.should be > 0
-    end
-
     context "returned MatchData" do
       describe "#matched?" do
-        context "given a Range" do
-          context "inclusive" do
-            it "is true for lower-bound" do
-              lower = 3
-              upper = 9
-              value = lower
-              range = Range.new(lower, upper, exclusive: false)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_true
-            end
-
-            it "is false for lower-bound minus 1" do
-              lower = 3
-              upper = 9
-              value = lower - 1
-              range = Range.new(lower, upper, exclusive: false)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_false
-            end
-
-            it "is true for mid-range" do
-              lower = 3
-              upper = 9
-              value = 5
-              range = Range.new(lower, upper, exclusive: false)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_true
-            end
-
-            it "is true for upper-bound" do
-              lower = 3
-              upper = 9
-              value = upper
-              range = Range.new(lower, upper, exclusive: false)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_true
-            end
-
-            it "is false for upper-bound plus 1" do
-              lower = 3
-              upper = 9
-              value = upper + 1
-              range = Range.new(lower, upper, exclusive: false)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_false
-            end
-          end
-
-          context "exclusive" do
-            it "is true for lower-bound" do
-              lower = 3
-              upper = 9
-              value = lower
-              range = Range.new(lower, upper, exclusive: true)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_true
-            end
-
-            it "is false for lower-bound minus 1" do
-              lower = 3
-              upper = 9
-              value = lower - 1
-              range = Range.new(lower, upper, exclusive: true)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_false
-            end
-
-            it "is true for mid-range" do
-              lower = 3
-              upper = 9
-              value = 5
-              range = Range.new(lower, upper, exclusive: true)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_true
-            end
-
-            it "is false for upper-bound" do
-              lower = 3
-              upper = 9
-              value = upper
-              range = Range.new(lower, upper, exclusive: true)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_false
-            end
-
-            it "is false for upper-bound plus 1" do
-              lower = 3
-              upper = 9
-              value = upper + 1
-              range = Range.new(lower, upper, exclusive: true)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data.matched?.should be_false
-            end
-          end
-        end
-
-        context "given an Enumerable" do
-          it "is true for an existing item" do
-            array = %i[a b c]
-            value = :b
+        context "inclusive" do
+          it "is true for lower-bound" do
+            lower = 3
+            upper = 9
+            value = lower
+            range = Range.new(lower, upper, exclusive: false)
             partial = new_partial(value)
-            matcher = Spectator::Matchers::RangeMatcher.new(array)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
             match_data = matcher.match(partial)
             match_data.matched?.should be_true
           end
 
-          it "is false for a non-existing item" do
-            array = %i[a b c]
-            value = :z
+          it "is false for lower-bound minus 1" do
+            lower = 3
+            upper = 9
+            value = lower - 1
+            range = Range.new(lower, upper, exclusive: false)
             partial = new_partial(value)
-            matcher = Spectator::Matchers::RangeMatcher.new(array)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+
+          it "is true for mid-range" do
+            lower = 3
+            upper = 9
+            value = 5
+            range = Range.new(lower, upper, exclusive: false)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
+          end
+
+          it "is true for upper-bound" do
+            lower = 3
+            upper = 9
+            value = upper
+            range = Range.new(lower, upper, exclusive: false)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
+          end
+
+          it "is false for upper-bound plus 1" do
+            lower = 3
+            upper = 9
+            value = upper + 1
+            range = Range.new(lower, upper, exclusive: false)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+        end
+
+        context "exclusive" do
+          it "is true for lower-bound" do
+            lower = 3
+            upper = 9
+            value = lower
+            range = Range.new(lower, upper, exclusive: true)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
+          end
+
+          it "is false for lower-bound minus 1" do
+            lower = 3
+            upper = 9
+            value = lower - 1
+            range = Range.new(lower, upper, exclusive: true)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+
+          it "is true for mid-range" do
+            lower = 3
+            upper = 9
+            value = 5
+            range = Range.new(lower, upper, exclusive: true)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_true
+          end
+
+          it "is false for upper-bound" do
+            lower = 3
+            upper = 9
+            value = upper
+            range = Range.new(lower, upper, exclusive: true)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data.matched?.should be_false
+          end
+
+          it "is false for upper-bound plus 1" do
+            lower = 3
+            upper = 9
+            value = upper + 1
+            range = Range.new(lower, upper, exclusive: true)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
             match_data = matcher.match(partial)
             match_data.matched?.should be_false
           end
@@ -150,88 +120,62 @@ describe Spectator::Matchers::RangeMatcher do
       end
 
       describe "#values" do
-        context "given a Range" do
-          context "lower" do
-            it "is #begin from the expected range" do
-              range = Range.new(3, 9)
-              partial = new_partial(5)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :lower)[:value].should eq(range.begin)
-            end
+        context "lower" do
+          it "is #begin from the expected range" do
+            range = Range.new(3, 9)
+            partial = new_partial(5)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data_value_sans_prefix(match_data.values, :lower)[:value].should eq(range.begin)
+          end
 
-            it "is prefixed with >=" do
-              range = Range.new(3, 9)
+          it "is prefixed with >=" do
+            range = Range.new(3, 9)
+            partial = new_partial(5)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data_value_sans_prefix(match_data.values, :lower)[:to_s].should start_with(">=")
+          end
+        end
+
+        context "upper" do
+          it "is #end from the expected range" do
+            range = Range.new(3, 9)
+            partial = new_partial(5)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data_value_sans_prefix(match_data.values, :upper)[:value].should eq(range.end)
+          end
+
+          context "when inclusive" do
+            it "is prefixed with <=" do
+              range = Range.new(3, 9, exclusive: false)
               partial = new_partial(5)
               matcher = Spectator::Matchers::RangeMatcher.new(range)
               match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :lower)[:to_s].should start_with(">=")
+              match_data_value_sans_prefix(match_data.values, :upper)[:to_s].should start_with("<=")
             end
           end
 
-          context "upper" do
-            it "is #end from the expected range" do
-              range = Range.new(3, 9)
+          context "when exclusive" do
+            it "is prefixed with <" do
+              range = Range.new(3, 9, exclusive: false)
               partial = new_partial(5)
               matcher = Spectator::Matchers::RangeMatcher.new(range)
               match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :upper)[:value].should eq(range.end)
-            end
-
-            context "when inclusive" do
-              it "is prefixed with <=" do
-                range = Range.new(3, 9, exclusive: false)
-                partial = new_partial(5)
-                matcher = Spectator::Matchers::RangeMatcher.new(range)
-                match_data = matcher.match(partial)
-                match_data_value_sans_prefix(match_data.values, :upper)[:to_s].should start_with("<=")
-              end
-            end
-
-            context "when exclusive" do
-              it "is prefixed with <" do
-                range = Range.new(3, 9, exclusive: false)
-                partial = new_partial(5)
-                matcher = Spectator::Matchers::RangeMatcher.new(range)
-                match_data = matcher.match(partial)
-                match_data_value_sans_prefix(match_data.values, :upper)[:to_s].should start_with("<")
-              end
-            end
-          end
-
-          context "actual" do
-            it "is the actual value" do
-              value = 5
-              range = Range.new(3, 9)
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(range)
-              match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :actual)[:value].should eq(value)
+              match_data_value_sans_prefix(match_data.values, :upper)[:to_s].should start_with("<")
             end
           end
         end
 
-        context "given an Enumerable" do
-          context "set" do
-            it "is the expected value" do
-              array = %i[a b c]
-              value = :z
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(array)
-              match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :set)[:value].should eq(array)
-            end
-          end
-
-          context "actual" do
-            it "is the actual value" do
-              array = %i[a b c]
-              value = :z
-              partial = new_partial(value)
-              matcher = Spectator::Matchers::RangeMatcher.new(array)
-              match_data = matcher.match(partial)
-              match_data_value_sans_prefix(match_data.values, :actual)[:value].should eq(value)
-            end
+        context "actual" do
+          it "is the actual value" do
+            value = 5
+            range = Range.new(3, 9)
+            partial = new_partial(value)
+            matcher = Spectator::Matchers::RangeMatcher.new(range)
+            match_data = matcher.match(partial)
+            match_data_value_sans_prefix(match_data.values, :actual)[:value].should eq(value)
           end
         end
       end
@@ -304,128 +248,6 @@ describe Spectator::Matchers::RangeMatcher do
     end
   end
 
-  describe "#of" do
-    it "is true for lower-bound" do
-      center = 5
-      diff = 4
-      lower = center - diff
-      value = lower
-      partial = new_partial(value)
-      matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-      match_data = matcher.match(partial)
-      match_data.matched?.should be_true
-    end
-
-    it "is false for lower-bound minus 1" do
-      center = 5
-      diff = 4
-      lower = center - diff
-      value = lower - 1
-      partial = new_partial(value)
-      matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-      match_data = matcher.match(partial)
-      match_data.matched?.should be_false
-    end
-
-    it "is true for mid-range" do
-      center = 5
-      diff = 4
-      value = center
-      partial = new_partial(value)
-      matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-      match_data = matcher.match(partial)
-      match_data.matched?.should be_true
-    end
-
-    it "is true for upper-bound" do
-      center = 5
-      diff = 4
-      upper = center + diff
-      value = upper
-      partial = new_partial(value)
-      matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-      match_data = matcher.match(partial)
-      match_data.matched?.should be_true
-    end
-
-    it "is false for upper-bound plus 1" do
-      center = 5
-      diff = 4
-      upper = center + diff
-      value = upper + 1
-      partial = new_partial(value)
-      matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-      match_data = matcher.match(partial)
-      match_data.matched?.should be_false
-    end
-
-    describe "#message" do
-      it "contains the original label" do
-        center = 5
-        diff = 4
-        value = 3
-        label = "foobar"
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff, label).of(center)
-        match_data = matcher.match(partial)
-        match_data.message.should contain(label)
-      end
-
-      it "contains the center" do
-        center = 5
-        diff = 4
-        value = 3
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-        match_data = matcher.match(partial)
-        match_data.message.should contain(center.to_s)
-      end
-
-      it "contains the diff" do
-        center = 5
-        diff = 4
-        value = 3
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-        match_data = matcher.match(partial)
-        match_data.message.should contain(diff.to_s)
-      end
-    end
-
-    describe "#negated_message" do
-      it "contains the original label" do
-        center = 5
-        diff = 4
-        value = 3
-        label = "foobar"
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff, label).of(center)
-        match_data = matcher.match(partial)
-        match_data.negated_message.should contain(label)
-      end
-
-      it "contains the center" do
-        center = 5
-        diff = 4
-        value = 3
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-        match_data = matcher.match(partial)
-        match_data.negated_message.should contain(center.to_s)
-      end
-
-      it "contains the diff" do
-        center = 5
-        diff = 4
-        value = 3
-        partial = new_partial(value)
-        matcher = Spectator::Matchers::RangeMatcher.new(diff).of(center)
-        match_data = matcher.match(partial)
-        match_data.negated_message.should contain(diff.to_s)
-      end
-    end
-  end
-
   describe "#inclusive" do
     context "initially exclusive" do
       it "is true for lower-bound" do
diff --git a/src/spectator/dsl/matcher_dsl.cr b/src/spectator/dsl/matcher_dsl.cr
index 5fdbe2c..7d14334 100644
--- a/src/spectator/dsl/matcher_dsl.cr
+++ b/src/spectator/dsl/matcher_dsl.cr
@@ -242,7 +242,7 @@ module Spectator::DSL
     # ```
     #
     # NOTE: The of suffix must be used
-    # if the *expected* argument does not implement an includes? method.
+    # if the *expected* argument does not implement an `includes?` method.
     #
     # Additionally, for this second usage,
     # an "inclusive" or "exclusive" suffix can be added.
@@ -258,7 +258,7 @@ module Spectator::DSL
     # NOTE: Do not attempt to mix the two use cases.
     # It likely won't work and will result in a compilation error.
     macro be_within(expected)
-      ::Spectator::Matchers::RangeMatcher.new({{expected}}, {{expected.stringify}})
+      ::Spectator::Matchers::CollectionMatcher.new({{expected}}, {{expected.stringify}})
     end
 
     # Indicates that some value should be between a lower and upper-bound.
diff --git a/src/spectator/matchers/collection_matcher.cr b/src/spectator/matchers/collection_matcher.cr
new file mode 100644
index 0000000..f57d46c
--- /dev/null
+++ b/src/spectator/matchers/collection_matcher.cr
@@ -0,0 +1,67 @@
+require "./value_matcher"
+
+module Spectator::Matchers
+  # Matcher for checking that a value is in a collection of other values.
+  struct CollectionMatcher(ExpectedType) < ValueMatcher(ExpectedType)
+    # Determines whether the matcher is satisfied with the value given to it.
+    private def match?(actual)
+      expected.includes?(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)
+      actual = partial.actual
+      matched = match?(actual)
+      MatchData.new(matched, ExpectedActual.new(partial, self))
+    end
+
+    # Creates a new range matcher with bounds based off of *center*.
+    #
+    # This method expects that the original matcher was created with a "difference" value.
+    # That is:
+    # ```
+    # RangeMatcher.new(diff).of(center)
+    # ```
+    # This implies that the `#match` method would not work on the original matcher.
+    #
+    # The new range will be centered at *center*
+    # and have upper and lower bounds equal to *center* plus and minus diff.
+    # The range will be inclusive.
+    def of(center)
+      diff = @expected
+      lower = center - diff
+      upper = center + diff
+      range = Range.new(lower, upper)
+      RangeMatcher.new(range, "#{center} +/- #{label}")
+    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 named_tuple
+        {
+          collection: NegatableMatchDataValue.new(@values.expected),
+          actual:     @values.actual,
+        }
+      end
+
+      # Describes the condition that satisfies the matcher.
+      # This is informational and displayed to the end-user.
+      def message
+        "#{@values.actual_label} is in #{@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
+        "#{@values.actual_label} is not in #{@values.expected_label}"
+      end
+    end
+  end
+end
diff --git a/src/spectator/matchers/range_matcher.cr b/src/spectator/matchers/range_matcher.cr
index 8b66497..ad05da3 100644
--- a/src/spectator/matchers/range_matcher.cr
+++ b/src/spectator/matchers/range_matcher.cr
@@ -1,10 +1,8 @@
 require "./value_matcher"
 
 module Spectator::Matchers
-  # Matcher that tests whether a value is in a given range or set of values.
-  # The `includes?` method is used for this check.
-  # Typically this matcher uses a `Range`,
-  # but any type that implements the `includes?` method is supported.
+  # Matcher that tests whether a value is in a given range.
+  # The `Range#includes?` method is used for this check.
   struct RangeMatcher(ExpectedType) < ValueMatcher(ExpectedType)
     # Determines whether the matcher is satisfied with the value given to it.
     private def match?(actual)
@@ -17,31 +15,7 @@ module Spectator::Matchers
       actual = partial.actual
       matched = match?(actual)
       expected_value = @expected
-      if expected_value.is_a?(Range)
-        RangeMatchData.new(matched, ExpectedActual.new(expected_value, label, actual, partial.label))
-      else
-        SetMatchData.new(matched, ExpectedActual.new(partial, self))
-      end
-    end
-
-    # Creates a new range matcher with bounds based off of *center*.
-    #
-    # This method expects that the original matcher was created with a "difference" value.
-    # That is:
-    # ```
-    # RangeMatcher.new(diff).of(center)
-    # ```
-    # This implies that the `#match` method would not work on the original matcher.
-    #
-    # The new range will be centered at *center*
-    # and have upper and lower bounds equal to *center* plus and minus diff.
-    # The range will be inclusive.
-    def of(center)
-      diff = @expected
-      lower = center - diff
-      upper = center + diff
-      range = Range.new(lower, upper)
-      RangeMatcher.new(range, "#{center} +/- #{label}")
+      MatchData.new(matched, ExpectedActual.new(expected_value, label, actual, partial.label))
     end
 
     # Returns a new matcher, with the same bounds, but uses an inclusive range.
@@ -58,7 +32,7 @@ module Spectator::Matchers
 
     # Match data specific to this matcher.
     # This is used when the expected type is a `Range`.
-    private struct RangeMatchData(B, E, ActualType) < MatchData
+    private struct MatchData(B, E, ActualType) < MatchData
       # Creates the match data.
       def initialize(matched, @values : ExpectedActual(Range(B, E), ActualType))
         super(matched)
@@ -100,34 +74,5 @@ module Spectator::Matchers
         exclusive? ? "exclusive" : "inclusive"
       end
     end
-
-    # Match data specific to this matcher.
-    # This is used when the expected type is not a `Range`.
-    private struct SetMatchData(ExpectedType, ActualType) < MatchData
-      # Creates the match data.
-      def initialize(matched, @values : ExpectedActual(ExpectedType, ActualType))
-        super(matched)
-      end
-
-      # Information about the match.
-      def named_tuple
-        {
-          set:    NegatableMatchDataValue.new(@values.expected),
-          actual: @values.actual,
-        }
-      end
-
-      # Describes the condition that satisfies the matcher.
-      # This is informational and displayed to the end-user.
-      def message
-        "#{@values.actual_label} is in #{@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
-        "#{@values.actual_label} is not in #{@values.expected_label}"
-      end
-    end
   end
 end