1 files changed, 27 insertions, 0 deletions
diff --git a/spec/ruby/optional/capi/string_spec.rb b/spec/ruby/optional/capi/string_spec.rb
index 3cd88a7390..ce387ffa49 100644
--- a/spec/ruby/optional/capi/string_spec.rb
+++ b/spec/ruby/optional/capi/string_spec.rb
@@ -1209,4 +1209,31 @@ end
       str.should == "test fmt 41 6 number"
     end
   end
+
+  describe "rb_str_locktmp" do
+    it "raises an error when trying to lock an already locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { @s.rb_str_locktmp(str) }.should raise_error(RuntimeError, 'temporal locking already locked string')
+    end
+
+    it "locks a string so that modifications would raise an error" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { str.upcase! }.should raise_error(RuntimeError, 'can\'t modify string; temporarily locked')
+    end
+  end
+
+  describe "rb_str_unlocktmp" do
+    it "unlocks a locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str)
+      @s.rb_str_unlocktmp(str).should == str
+      str.upcase!.should == "TEST"
+    end
+
+    it "raises an error when trying to unlock an already unlocked string" do
+      -> { @s.rb_str_unlocktmp("test") }.should raise_error(RuntimeError, 'temporal unlocking already unlocked string')
+    end
+  end
 end