diff --git a/tests/misc_tests.c b/tests/misc_tests.c
index 518ac72..47dff72 100644
--- a/tests/misc_tests.c
+++ b/tests/misc_tests.c
@@ -127,6 +127,62 @@ static void cjson_get_object_item_case_sensitive_should_get_object_items(void)
     cJSON_Delete(item);
 }
 
+static void typecheck_functions_should_check_type(void)
+{
+    cJSON invalid[1];
+    cJSON item[1];
+    invalid->type = cJSON_Invalid;
+    invalid->type |= cJSON_StringIsConst;
+    item->type = cJSON_False;
+    item->type |= cJSON_StringIsConst;
+
+    TEST_ASSERT_FALSE(cJSON_IsInvalid(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsInvalid(item));
+    TEST_ASSERT_TRUE(cJSON_IsInvalid(invalid));
+
+    item->type = cJSON_False | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsFalse(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsFalse(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsFalse(item));
+    TEST_ASSERT_TRUE(cJSON_IsBool(item));
+
+    item->type = cJSON_True | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsTrue(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsTrue(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsTrue(item));
+    TEST_ASSERT_TRUE(cJSON_IsBool(item));
+
+    item->type = cJSON_NULL | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsNull(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsNull(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsNull(item));
+
+    item->type = cJSON_Number | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsNumber(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsNumber(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsNumber(item));
+
+    item->type = cJSON_String | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsString(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsString(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsString(item));
+
+    item->type = cJSON_Array | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsArray(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsArray(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsArray(item));
+
+    item->type = cJSON_Object | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsObject(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsObject(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsObject(item));
+
+    item->type = cJSON_Raw | cJSON_StringIsConst;
+    TEST_ASSERT_FALSE(cJSON_IsRaw(NULL));
+    TEST_ASSERT_FALSE(cJSON_IsRaw(invalid));
+    TEST_ASSERT_TRUE(cJSON_IsRaw(item));
+}
+
 int main(void)
 {
     UNITY_BEGIN();
@@ -135,6 +191,7 @@ int main(void)
     RUN_TEST(cjson_array_foreach_should_not_dereference_null_pointer);
     RUN_TEST(cjson_get_object_item_should_get_object_items);
     RUN_TEST(cjson_get_object_item_case_sensitive_should_get_object_items);
+    RUN_TEST(typecheck_functions_should_check_type);
 
     return UNITY_END();
 }