Add specs for error handling in MatchData#begin

Author: rwstauner

spec/ruby/core/matchdata/begin_spec.rb

@@ -36,6 +36,18 @@
       match_data = /(.)(.)(\d+)(\d)/.match("THX1138.")
       match_data.begin(obj).should == 2
     end
+
+    it "raises IndexError if index is out of matches" do
+      match_data = /(?<f>foo)(?<b>bar)/.match("foobar")
+
+      -> {
+        match_data.begin(-1)
+      }.should raise_error(IndexError, "index -1 out of matches")
+
+      -> {
+        match_data.begin(3)
+      }.should raise_error(IndexError, "index 3 out of matches")
+    end
   end
 
   context "when passed a String argument" do
@@ -68,6 +80,14 @@
       match_data = /(?<æ>.)(.)(?<b>\d+)(\d)/.match("THX1138.")
       match_data.begin("æ").should == 1
     end
+
+    it "raises IndexError if there is no group with the provided name" do
+      match_data = /(?<f>foo)(?<b>bar)/.match("foobar")
+
+      -> {
+        match_data.begin("y")
+      }.should raise_error(IndexError, "undefined group name reference: y")
+    end
   end
 
   context "when passed a Symbol argument" do
@@ -100,5 +120,13 @@
       match_data = /(?<æ>.)(.)(?<b>\d+)(\d)/.match("THX1138.")
       match_data.begin(:æ).should == 1
     end
+
+    it "raises IndexError if there is no group with the provided name" do
+      match_data = /(?<f>foo)(?<b>bar)/.match("foobar")
+
+      -> {
+        match_data.begin(:y)
+      }.should raise_error(IndexError, "undefined group name reference: y")
+    end
   end
 end

spec/ruby/core/matchdata/byteoffset_spec.rb

@@ -60,7 +60,7 @@ def obj.to_int; 2; end
       m.byteoffset(obj).should == [3, 6]
     end
 
-    it "raises IndexError if there is no group with provided name" do
+    it "raises IndexError if there is no group with the provided name" do
       m = /(?<f>foo)(?<b>bar)/.match("foobar")
 
       -> {