1 files changed, 69 insertions, 0 deletions
diff --git a/spec/ruby/core/string/chilled_string_spec.rb b/spec/ruby/core/string/chilled_string_spec.rb
new file mode 100644
index 0000000000..8de4fc421b
--- /dev/null
+++ b/spec/ruby/core/string/chilled_string_spec.rb
@@ -0,0 +1,69 @@
+require_relative '../../spec_helper'
+
+describe "chilled String" do
+  guard -> { ruby_version_is "3.4" and !"test".equal?("test") } do
+    describe "#frozen?" do
+      it "returns true" do
+        "chilled".frozen?.should == true
+      end
+    end
+
+    describe "#-@" do
+      it "returns a different instance" do
+        input = "chilled"
+        interned = (-input)
+        interned.frozen?.should == true
+        interned.object_id.should_not == input.object_id
+      end
+    end
+
+    describe "#+@" do
+      it "returns a different instance" do
+        input = "chilled"
+        duped = (+input)
+        duped.frozen?.should == false
+        duped.object_id.should_not == input.object_id
+      end
+    end
+
+    describe "#clone" do
+      it "preserves chilled status" do
+        input = "chilled".clone
+        -> {
+          input << "-mutated"
+        }.should complain(/literal string will be frozen in the future/)
+        input.should == "chilled-mutated"
+      end
+    end
+
+    describe "mutation" do
+      it "emits a warning" do
+        input = "chilled"
+        -> {
+          input << "-mutated"
+        }.should complain(/literal string will be frozen in the future/)
+        input.should == "chilled-mutated"
+      end
+
+      it "emits a warning on singleton_class creaation" do
+        -> {
+          "chilled".singleton_class
+        }.should complain(/literal string will be frozen in the future/)
+      end
+
+      it "emits a warning on instance variable assignment" do
+        -> {
+          "chilled".instance_variable_set(:@ivar, 42)
+        }.should complain(/literal string will be frozen in the future/)
+      end
+
+      it "raises FrozenError after the string was explictly frozen" do
+        input = "chilled"
+        input.freeze
+        -> {
+          input << "mutated"
+        }.should raise_error(FrozenError)
+      end
+    end
+  end
+end