Replace VersionChecker with ComparableVersion

Author: yujinakayama

Changelog.md

@@ -4,6 +4,7 @@ Enhancements:
 
 * Improve formatting of `Delegator` based objects (e.g. `SimpleDelgator`) in
   failure messages and diffs. (Andrew Horner, #215)
+* Replace `VersionChecker` with `ComparableVersion` (Yuji Nakayama, #245).
 
 Bug Fixes:
 

lib/rspec/support/comparable_version.rb

@@ -0,0 +1,35 @@
+module RSpec
+  module Support
+    # @private
+    class ComparableVersion
+      include Comparable
+
+      attr_reader :string
+
+      def initialize(string)
+        @string = string
+      end
+
+      def <=>(other)
+        other = self.class.new(other) unless other.is_a?(self.class)
+
+        return 0 if string == other.string
+
+        longer_segment_count = [self, other].map { |version| version.segments.count }.max
+
+        longer_segment_count.times do |index|
+          self_segment = segments[index] || 0
+          other_segment = other.segments[index] || 0
+          result = self_segment <=> other_segment
+          return result unless result == 0
+        end
+
+        0
+      end
+
+      def segments
+        @segments ||= string.split('.').map { |v| v.to_i }
+      end
+    end
+  end
+end

lib/rspec/support/version_checker.rb

@@ -0,0 +1,31 @@
+require 'rspec/support/comparable_version'
+
+module RSpec::Support
+  describe ComparableVersion do
+    describe '#<=>' do
+      [
+        ['1.2.3',   '1.2.3',    0],
+        ['1.2.4',   '1.2.3',    1],
+        ['1.3.0',   '1.2.3',    1],
+        ['1.2.3',   '1.2.4',   -1],
+        ['1.2.3',   '1.3.0',   -1],
+        ['1.2.10',  '1.2.3',    1],
+        ['1.2.3',   '1.2.10',  -1],
+        ['1.2.3.0', '1.2.3',    0],
+        ['1.2.3',   '1.2.3.0',  0],
+        ['1.2.3.1', '1.2.3',    1],
+        ['1.2.3.1', '1.2.3.0',  1],
+        ['1.2.3',   '1.2.3.1', -1],
+        ['1.2.3.0', '1.2.3.1', -1]
+      ].each do |subject_string, other_string, expected|
+        context "with #{subject_string.inspect} and #{other_string.inspect}" do
+          subject do
+            ComparableVersion.new(subject_string) <=> ComparableVersion.new(other_string)
+          end
+
+          it { should eq(expected) }
+        end
+      end
+    end
+  end
+end