1 files changed, 77 insertions, 0 deletions
diff --git a/spec/ruby/library/stringscanner/check_spec.rb b/spec/ruby/library/stringscanner/check_spec.rb
index c7f788f0b3..232158b09e 100644
--- a/spec/ruby/library/stringscanner/check_spec.rb
+++ b/spec/ruby/library/stringscanner/check_spec.rb
@@ -13,4 +13,81 @@ describe "StringScanner#check" do
     @s.check(/is/).should == nil
     @s.matched.should == nil
   end
+
+  it "treats String as the pattern itself" do
+    @s.check("This").should == "This"
+    @s.matched.should == "This"
+    @s.pos.should == 0
+    @s.check(/is/).should == nil
+    @s.matched.should == nil
+  end
+
+  describe "#[] successive call with a capture group name" do
+    context "when #check was called with a Regexp pattern" do
+      it "returns matched substring when matching succeeded" do
+        @s.check(/(?<a>This)/)
+        @s.should.matched?
+        @s[:a].should == "This"
+      end
+
+      it "returns nil when matching failed" do
+        @s.check(/(?<a>2008)/)
+        @s.should_not.matched?
+        @s[:a].should == nil
+      end
+    end
+
+    context "when #check was called with a String pattern" do
+      # https://github.com/ruby/strscan/issues/139
+      version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
+        it "returns nil when matching succeeded" do
+          @s.check("This")
+          @s.should.matched?
+          @s[:a].should == nil
+        end
+      end
+      version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4"
+        it "raises IndexError when matching succeeded" do
+          @s.check("This")
+          @s.should.matched?
+          -> { @s[:a] }.should.raise(IndexError)
+        end
+      end
+
+      it "returns nil when matching failed" do
+        @s.check("2008")
+        @s.should_not.matched?
+        @s[:a].should == nil
+      end
+
+      it "returns a matching substring when given Integer index" do
+        @s.check("This")
+        @s[0].should == "This"
+      end
+
+      # https://github.com/ruby/strscan/issues/135
+      version_is StringScanner::Version, "3.1.1"..."3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
+        it "ignores the previous matching with Regexp" do
+          @s.exist?(/(?<a>This)/)
+          @s.should.matched?
+          @s[:a].should == "This"
+
+          @s.check("This")
+          @s.should.matched?
+          @s[:a].should == nil
+        end
+      end
+      version_is StringScanner::Version, "3.1.3" do # ruby_version_is "3.4.0"..."3.4.3"
+        it "ignores the previous matching with Regexp" do
+          @s.exist?(/(?<a>This)/)
+          @s.should.matched?
+          @s[:a].should == "This"
+
+          @s.check("This")
+          @s.should.matched?
+          -> { @s[:a] }.should.raise(IndexError)
+        end
+      end
+    end
+  end
 end