Make Example comparable against names and sources

This will be needed for filtering examples.

spec/pending_example_spec.cr

@@ -119,4 +119,66 @@ describe Spectator::PendingExample do
       example.to_s.should contain(group.what.to_s)
     end
   end
+
+  describe "#===" do
+    context "with a matching Regex" do
+      it "is true" do
+        example = new_pending_example
+        regex = Regex.new(Regex.escape(example.what))
+        (example === regex).should be_true
+      end
+    end
+
+    context "with a non-matching Regex" do
+      it "is false" do
+        example = new_pending_example
+        regex = /BOGUS/
+        (example === regex).should be_false
+      end
+    end
+
+    context "with a String equal to the name" do
+      it "is true" do
+        example = new_pending_example
+        (example === example.to_s).should be_true
+      end
+    end
+
+    context "with a String different than the name" do
+      it "is false" do
+        example = new_pending_example
+        (example === "BOGUS").should be_false
+      end
+    end
+
+    context "with a matching source location" do
+      it "is true" do
+        example = new_pending_example
+        (example === example.source).should be_true
+      end
+    end
+
+    context "with a non-matching source location" do
+      it "is false" do
+        example = new_pending_example
+        source = Spectator::Source.new(__FILE__, __LINE__)
+        (example === source).should be_false
+      end
+    end
+
+    context "with a matching source line" do
+      it "is true" do
+        example = new_pending_example
+        (example === example.source.line).should be_true
+      end
+    end
+
+    context "with a non-matching source line" do
+      it "is false" do
+        example = new_pending_example
+        line = example.source.line + 5
+        (example === line).should be_false
+      end
+    end
+  end
 end

spec/runnable_example_spec.cr

@@ -1565,4 +1565,66 @@ describe Spectator::RunnableExample do
       end
     end
   end
+
+  describe "#===" do
+    context "with a matching Regex" do
+      it "is true" do
+        example = new_runnable_example
+        regex = Regex.new(Regex.escape(example.what))
+        (example === regex).should be_true
+      end
+    end
+
+    context "with a non-matching Regex" do
+      it "is false" do
+        example = new_runnable_example
+        regex = /BOGUS/
+        (example === regex).should be_false
+      end
+    end
+
+    context "with a String equal to the name" do
+      it "is true" do
+        example = new_runnable_example
+        (example === example.to_s).should be_true
+      end
+    end
+
+    context "with a String different than the name" do
+      it "is false" do
+        example = new_runnable_example
+        (example === "BOGUS").should be_false
+      end
+    end
+
+    context "with a matching source location" do
+      it "is true" do
+        example = new_runnable_example
+        (example === example.source).should be_true
+      end
+    end
+
+    context "with a non-matching source location" do
+      it "is false" do
+        example = new_runnable_example
+        source = Spectator::Source.new(__FILE__, __LINE__)
+        (example === source).should be_false
+      end
+    end
+
+    context "with a matching source line" do
+      it "is true" do
+        example = new_runnable_example
+        (example === example.source.line).should be_true
+      end
+    end
+
+    context "with a non-matching source line" do
+      it "is false" do
+        example = new_runnable_example
+        line = example.source.line + 5
+        (example === line).should be_false
+      end
+    end
+  end
 end

src/spectator/example.cr

@@ -59,5 +59,21 @@ module Spectator
     def to_json(json : ::JSON::Builder)
       json.string(to_s)
     end
+
+    # Checks if this example matches some criteria.
+    # This is used to filter examples.
+    def ===(other)
+      other === to_s
+    end
+
+    # Checks if this example is at the specified source.
+    def ===(other : Source)
+      source == other
+    end
+
+    # Checks if this example is at the specified line number.
+    def ===(other : Int32)
+      source.line === other
+    end
   end
 end