Added explicit null for json parser, and also added tests to verify null behavior. (aws#28)

Author: JonathanHenson

include/aws/crt/JsonObject.h

@@ -154,6 +154,11 @@ namespace Aws
              */
             JsonObject &AsArray(Vector<JsonObject> &&array);
 
+            /**
+             * Sets the current JSON node as null.
+             */
+            JsonObject &AsNull();
+
             /**
              * Adds a JSON object to the top level of this node at key.
              * The object parameter is deep-copied.

source/JsonObject.cpp

@@ -281,6 +281,12 @@ namespace Aws
             return *this;
         }
 
+        JsonObject &JsonObject::AsNull()
+        {
+            m_value = cJSON_CreateNull();
+            return *this;
+        }
+
         JsonObject &JsonObject::WithObject(const char *key, const JsonObject &value)
         {
             if (m_value == nullptr)

tests/CMakeLists.txt

@@ -14,6 +14,9 @@ add_test_case(ClientBootstrapResourceSafety)
 add_test_case(TLSContextResourceSafety)
 add_test_case(DateTimeBinding)
 add_test_case(BasicJsonParsing)
+add_test_case(JsonNullParsing)
+add_test_case(JsonNullNestedObject)
+add_test_case(JsonExplicitNull)
 add_test_case(SHA256ResourceSafety)
 add_test_case(MD5ResourceSafety)
 add_test_case(SHA256HMACResourceSafety)

tests/JsonParserTest.cpp

@@ -42,3 +42,75 @@ static int s_BasicJsonParsing(struct aws_allocator *allocator, void *ctx)
 }
 
 AWS_TEST_CASE(BasicJsonParsing, s_BasicJsonParsing)
+
+static int s_JsonNullParseTest(struct aws_allocator *allocator, void *ctx)
+{
+    (void)ctx;
+    Aws::Crt::ApiHandle apiHandle(allocator);
+
+    const Aws::Crt::String jsonValue = "{\"testStringKey\":null,\"testIntKey\":10,"
+                                       "\"array\":[null,\"stringArrayEntry\"],"
+                                       "\"object\":{\"testObjectStringKey\":null}}";
+
+    Aws::Crt::JsonObject value(jsonValue);
+    ASSERT_TRUE(value.WasParseSuccessful());
+
+    auto str = value.View().WriteCompact(true);
+    ASSERT_STR_EQUALS(jsonValue.c_str(), str.c_str());
+    str = value.View().WriteCompact(false);
+    ASSERT_STR_EQUALS(jsonValue.c_str(), str.c_str());
+
+    return AWS_OP_SUCCESS;
+}
+
+AWS_TEST_CASE(JsonNullParsing, s_JsonNullParseTest)
+
+static int s_JsonNullNestedObjectTest(struct aws_allocator *allocator, void *ctx)
+{
+    (void)ctx;
+    Aws::Crt::ApiHandle apiHandle(allocator);
+
+    const Aws::Crt::String jsonValue = "{\"testStringKey\":null,\"testIntKey\":10,"
+                                       "\"array\":[null,\"stringArrayEntry\"],"
+                                       "\"object\":{\"testObjectStringKey\":null}}";
+
+    Aws::Crt::JsonObject value(jsonValue);
+    ASSERT_TRUE(value.WasParseSuccessful());
+
+    Aws::Crt::JsonObject doc;
+    doc.WithObject("null_members", jsonValue);
+
+    const Aws::Crt::String expectedValue = "{\"null_members\":{\"testStringKey\":null,\"testIntKey\":10,"
+                                           "\"array\":[null,\"stringArrayEntry\"],"
+                                           "\"object\":{\"testObjectStringKey\":null}}}";
+    auto str = doc.View().WriteCompact(true);
+    ASSERT_STR_EQUALS(expectedValue.c_str(), str.c_str());
+    str = doc.View().WriteCompact(false);
+    ASSERT_STR_EQUALS(expectedValue.c_str(), str.c_str());
+
+    return AWS_OP_SUCCESS;
+}
+
+AWS_TEST_CASE(JsonNullNestedObject, s_JsonNullNestedObjectTest)
+
+static int s_JsonExplicitNullTest(struct aws_allocator *allocator, void *ctx)
+{
+    (void)ctx;
+    Aws::Crt::ApiHandle apiHandle(allocator);
+
+    const Aws::Crt::String expectedValue = "{\"testKey\":null}";
+
+    Aws::Crt::JsonObject doc;
+    Aws::Crt::JsonObject nullObject;
+    nullObject.AsNull();
+    doc.WithObject("testKey", nullObject);
+
+    auto str = doc.View().WriteCompact(true);
+    ASSERT_STR_EQUALS(expectedValue.c_str(), str.c_str());
+    str = doc.View().WriteCompact(false);
+    ASSERT_STR_EQUALS(expectedValue.c_str(), str.c_str());
+
+    return AWS_OP_SUCCESS;
+}
+
+AWS_TEST_CASE(JsonExplicitNull, s_JsonExplicitNullTest)