1 files changed, 34 insertions, 0 deletions
diff --git a/spec/ruby/core/matchdata/match_length_spec.rb b/spec/ruby/core/matchdata/match_length_spec.rb
new file mode 100644
index 0000000000..f7785ab1a0
--- /dev/null
+++ b/spec/ruby/core/matchdata/match_length_spec.rb
@@ -0,0 +1,34 @@
+# -*- encoding: utf-8 -*-
+
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  describe "MatchData#match_length" do
+    it "returns the length of the corresponding match when given an Integer" do
+      md = /(.)(.)(\d+)(\d)/.match("THX1138.")
+
+      md.match_length(0).should == 6
+      md.match_length(1).should == 1
+      md.match_length(2).should == 1
+      md.match_length(3).should == 3
+      md.match_length(4).should == 1
+    end
+
+    it "returns nil on non-matching index matches" do
+      md = /\d+(\w)?/.match("THX1138.")
+      md.match_length(1).should == nil
+    end
+
+    it "returns the length of the corresponding named match when given a Symbol" do
+      md = 'haystack'.match(/(?<t>t(?<a>ack))/)
+      md.match_length(:a).should == 3
+      md.match_length(:t).should == 4
+    end
+
+    it "returns nil on non-matching index matches" do
+      md = 'haystack'.match(/(?<t>t)(?<a>all)?/)
+      md.match_length(:t).should == 1
+      md.match_length(:a).should == nil
+    end
+  end
+end