1 files changed, 52 insertions, 14 deletions
diff --git a/spec/ruby/optional/capi/string_spec.rb b/spec/ruby/optional/capi/string_spec.rb
index 18eaeda8e0..72f20ee6a5 100644
--- a/spec/ruby/optional/capi/string_spec.rb
+++ b/spec/ruby/optional/capi/string_spec.rb
@@ -191,11 +191,19 @@ describe "C-API String function" do
     end
 
     it "returns a new String object filled with \\0 bytes" do
-      s = @s.rb_str_tmp_new(4)
-      s.encoding.should == Encoding::BINARY
-      s.bytesize.should == 4
-      s.size.should == 4
-      s.should == "\x00\x00\x00\x00"
+      lens = [4]
+
+      ruby_version_is "4.0" do
+        lens << 100
+      end
+
+      lens.each do |len|
+        s = @s.rb_str_tmp_new(len)
+        s.encoding.should == Encoding::BINARY
+        s.bytesize.should == len
+        s.size.should == len
+        s.should == "\x00" * len
+      end
     end
   end
 
@@ -1040,11 +1048,19 @@ describe "C-API String function" do
       @s.rb_sprintf3(true.class).should == s
     end
 
-    ruby_bug "#19167", ""..."3.2" do
-      it "formats a TrueClass VALUE as 'true' if sign specified in format" do
-        s = 'Result: TrueClass.'
-        @s.rb_sprintf4(true.class).should == s
-      end
+    it "formats a TrueClass VALUE as 'true' if sign specified in format" do
+      s = 'Result: TrueClass.'
+      @s.rb_sprintf4(true.class).should == s
+    end
+
+    it "formats nil using to_s if sign not specified in format" do
+      s = 'Result: .'
+      @s.rb_sprintf3(nil).should == s
+    end
+
+    it "formats nil using inspect if sign specified in format" do
+      s = 'Result: nil.'
+      @s.rb_sprintf4(nil).should == s
     end
 
     it "truncates a string to a supplied precision if that is shorter than the string" do
@@ -1203,28 +1219,50 @@ describe "C-API String function" do
 
   describe "rb_str_locktmp" do
     it "raises an error when trying to lock an already locked string" do
-      str = "test"
+      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"
+      str = +"test"
       @s.rb_str_locktmp(str).should == str
       -> { str.upcase! }.should raise_error(RuntimeError, 'can\'t modify string; temporarily locked')
     end
+
+    ruby_version_is "4.0" do
+      it "raises FrozenError if string is frozen" do
+        str = -"rb_str_locktmp"
+        -> { @s.rb_str_locktmp(str) }.should raise_error(FrozenError)
+
+        str = +"rb_str_locktmp"
+        str.freeze
+        -> { @s.rb_str_locktmp(str) }.should raise_error(FrozenError)
+      end
+    end
   end
 
   describe "rb_str_unlocktmp" do
     it "unlocks a locked string" do
-      str = "test"
+      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')
+      -> { @s.rb_str_unlocktmp(+"test") }.should raise_error(RuntimeError, 'temporal unlocking already unlocked string')
+    end
+
+    ruby_version_is "4.0" do
+      it "raises FrozenError if string is frozen" do
+        str = -"rb_str_locktmp"
+        -> { @s.rb_str_unlocktmp(str) }.should raise_error(FrozenError)
+
+        str = +"rb_str_locktmp"
+        str.freeze
+        -> { @s.rb_str_unlocktmp(str) }.should raise_error(FrozenError)
+      end
     end
   end