1 files changed, 57 insertions, 0 deletions
diff --git a/test/ruby/test_frozen_error.rb b/test/ruby/test_frozen_error.rb
new file mode 100644
index 0000000000..ace1e4c775
--- /dev/null
+++ b/test/ruby/test_frozen_error.rb
@@ -0,0 +1,57 @@
+require 'test/unit'
+
+class TestFrozenError < Test::Unit::TestCase
+  def test_new_default
+    exc = FrozenError.new
+    assert_equal("FrozenError", exc.message)
+    assert_raise_with_message(ArgumentError, "no receiver is available") {
+      exc.receiver
+    }
+  end
+
+  def test_new_message
+    exc = FrozenError.new("bar")
+    assert_equal("bar", exc.message)
+    assert_raise_with_message(ArgumentError, "no receiver is available") {
+      exc.receiver
+    }
+  end
+
+  def test_new_receiver
+    obj = Object.new
+    exc = FrozenError.new("bar", receiver: obj)
+    assert_equal("bar", exc.message)
+    assert_same(obj, exc.receiver)
+  end
+
+  def test_message
+    obj = Object.new.freeze
+    e = assert_raise_with_message(FrozenError, /can't modify frozen #{obj.class}/) {
+      obj.instance_variable_set(:@test, true)
+    }
+    assert_include(e.message, obj.inspect)
+
+    klass = Class.new do
+      def init
+        @x = true
+      end
+      def inspect
+        init
+        super
+      end
+    end
+    obj = klass.new.freeze
+    e = assert_raise_with_message(FrozenError, /can't modify frozen #{obj.class}/) {
+      obj.init
+    }
+    assert_include(e.message, klass.inspect)
+  end
+
+  def test_receiver
+    obj = Object.new.freeze
+    e = assert_raise(FrozenError) {def obj.foo; end}
+    assert_same(obj, e.receiver)
+    e = assert_raise(FrozenError) {obj.singleton_class.const_set(:A, 2)}
+    assert_same(obj.singleton_class, e.receiver)
+  end
+end