Add Comparison operator to UUID (#11352)

Co-authored-by: Oleh Prypin <[email protected]>

spec/std/uuid_spec.cr

@@ -10,6 +10,16 @@ describe "UUID" do
     end
   end
 
+  describe "#<=>" do
+    it "correctly compares two UUIDs" do
+      uuid_1 = UUID.new("00330000-0000-0000-0000-000000000000")
+      uuid_2 = UUID.new("00000011-0000-0000-5500-000099000000")
+      (uuid_1 <=> uuid_2).should be > 0
+      (uuid_2 <=> uuid_1).should be < 0
+      (uuid_1 <=> uuid_1).should eq 0
+    end
+  end
+
   describe "random initialize" do
     it "works with no options" do
       subject = UUID.random

src/uuid.cr

@@ -1,5 +1,7 @@
 # Represents a UUID (Universally Unique IDentifier).
 struct UUID
+  include Comparable(UUID)
+
   # Variants with 16 bytes.
   enum Variant
     # Unknown (i.e. custom, your own).
@@ -207,6 +209,10 @@ struct UUID
     end
   end
 
+  def <=>(other : UUID) : Int32
+    @bytes <=> other.bytes
+  end
+
   class Error < Exception
   end