public void ShouldBeARegExp()
 {
     var value = new JsValue(new RegExpInstance(null));
     Assert.Equal(false, value.IsBoolean());
     Assert.Equal(false, value.IsArray());
     Assert.Equal(false, value.IsDate());
     Assert.Equal(false, value.IsNull());
     Assert.Equal(false, value.IsNumber());
     Assert.Equal(true, value.IsObject());
     Assert.Equal(false, value.IsPrimitive());
     Assert.Equal(true, value.IsRegExp());
     Assert.Equal(true, value.AsRegExp() != null);
     Assert.Equal(false, value.IsString());
     Assert.Equal(false, value.IsUndefined());
 }