1 files changed, 20 insertions, 0 deletions
diff --git a/spec/ruby/optional/capi/string_spec.rb b/spec/ruby/optional/capi/string_spec.rb
index 469a190abd..1cfd590ca4 100644
--- a/spec/ruby/optional/capi/string_spec.rb
+++ b/spec/ruby/optional/capi/string_spec.rb
@@ -977,4 +977,24 @@ end
     end
 
   end
+
+  describe "rb_str_drop_bytes" do
+    it "drops N characters for an ASCII string" do
+      str = "12345678".encode("US-ASCII")
+      @s.rb_str_drop_bytes(str, 4)
+      str.should == "5678".encode("US-ASCII")
+    end
+
+    it "drop N/2 characters for a UTF-16 string" do
+      str = "12345678".encode("UTF-16LE")
+      @s.rb_str_drop_bytes(str, 4)
+      str.should == "345678".encode("UTF-16LE")
+    end
+
+    it "drop N/4 characters for a UTF-32 string" do
+      str = "12345678".encode("UTF-32LE")
+      @s.rb_str_drop_bytes(str, 4)
+      str.should == "2345678".encode("UTF-32LE")
+    end
+  end
 end