Add optional fields also to the testing

PiperOrigin-RevId: 592030444

src/google/protobuf/json/json_test.cc

@@ -204,6 +204,9 @@ TEST_P(JsonTest, TestDefaultValues) {
 
   m.set_string_value("i am a test string value");
   m.set_bytes_value("i am a test bytes value");
+  m.set_optional_bool_value(false);
+  m.set_optional_string_value("");
+  m.set_optional_bytes_value("");
   EXPECT_THAT(
       ToJson(m, options),
       IsOkAndHolds("{\"boolValue\":false,"
@@ -226,7 +229,10 @@ TEST_P(JsonTest, TestDefaultValues) {
                    "\"repeatedStringValue\":[],"
                    "\"repeatedBytesValue\":[],"
                    "\"repeatedEnumValue\":[],"
-                   "\"repeatedMessageValue\":[]"
+                   "\"repeatedMessageValue\":[],"
+                   "\"optionalBoolValue\":false,"
+                   "\"optionalStringValue\":\"\","
+                   "\"optionalBytesValue\":\"\""
                    "}"));
 
   EXPECT_THAT(

src/google/protobuf/util/json_format_proto3.proto

@@ -54,6 +54,18 @@ message TestMessage {
   repeated bytes repeated_bytes_value = 29;
   repeated EnumType repeated_enum_value = 30;
   repeated MessageType repeated_message_value = 31;
+
+  optional bool optional_bool_value = 41;
+  optional int32 optional_int32_value = 42;
+  optional int64 optional_int64_value = 43;
+  optional uint32 optional_uint32_value = 44;
+  optional uint64 optional_uint64_value = 45;
+  optional float optional_float_value = 46;
+  optional double optional_double_value = 47;
+  optional string optional_string_value = 48;
+  optional bytes optional_bytes_value = 49;
+  optional EnumType optional_enum_value = 50;
+  optional MessageType optional_message_value = 51;
 }
 
 message TestOneof {