Update testlib.cpp

Author: anupriya13

vnext/ReactCommon/TEMP_UntilReactCommonUpdate/jsi/jsi/test/testlib.cpp

@@ -1551,7 +1551,7 @@ TEST_P(JSITest, UTF8ExceptionTest) {
 }
 
 /* [Windows #14185
-TEST_P(JSITest, UTF16Test) {
+TEST_P(JSITest, UTF16ConversionTest) {
   // This Runtime Decorator is used to test the conversion from UTF-8 to UTF-16
   // in the default utf16 method for runtimes that do not provide their own
   // utf16 implementation.
@@ -1614,6 +1614,50 @@ TEST_P(JSITest, UTF16Test) {
   rd.utf8Str = "\xea\x7a";
   EXPECT_EQ(str.utf16(rd), u"\uFFFD\u007A");
 }
+
+TEST_P(JSITest, CreateFromUtf16Test) {
+  // This Runtime Decorator is used to test the default createStringFromUtf16
+  // and createPropNameIDFromUtf16 implementation for VMs that do not provide
+  // their own implementation
+  class RD : public RuntimeDecorator<Runtime, Runtime> {
+   public:
+    RD(Runtime& rt) : RuntimeDecorator(rt) {}
+
+    String createStringFromUtf16(const char16_t* utf16, size_t length)
+        override {
+      return Runtime::createStringFromUtf16(utf16, length);
+    }
+
+    PropNameID createPropNameIDFromUtf16(const char16_t* utf16, size_t length)
+        override {
+      return Runtime::createPropNameIDFromUtf16(utf16, length);
+    }
+  };
+
+  RD rd = RD(rt);
+  std::u16string utf16 = u"foobar";
+
+  auto jsString = String::createFromUtf16(rd, utf16);
+  EXPECT_EQ(jsString.utf16(rd), utf16);
+  auto prop = PropNameID::forUtf16(rd, utf16);
+  EXPECT_EQ(prop.utf16(rd), utf16);
+
+  // 👋 in UTF-16 encoding is 0xd83d 0xdc4b
+  utf16 = u"hello!\xd83d\xdc4b";
+  jsString = String::createFromUtf16(rd, utf16.data(), utf16.length());
+  EXPECT_EQ(jsString.utf16(rd), utf16);
+  prop = PropNameID::forUtf16(rd, utf16);
+  EXPECT_EQ(prop.utf16(rd), utf16);
+
+  utf16 = u"\xd83d";
+  jsString = String::createFromUtf16(rd, utf16.data(), utf16.length());
+  /// We need to use charCodeAt instead of UTF16 because the default
+  /// implementation of UTF16 converts to UTF8, then to UTF16, so we will lose
+  /// the lone surrogate value.
+  rd.global().setProperty(rd, "loneSurrogate", jsString);
+  auto cp = eval("loneSurrogate.charCodeAt(0)").getNumber();
+  EXPECT_EQ(cp, 55357); // 0xD83D in decimal
+}
 Windows] */
 
 /*