Added curl holder double free tests

Author: COM8

test/CMakeLists.txt

@@ -72,6 +72,7 @@ add_cpr_test(threadpool)
 add_cpr_test(testUtils)
 add_cpr_test(connection_pool)
 add_cpr_test(sse)
+add_cpr_test(curlholder)
 
 if (ENABLE_SSL_TESTS)
     add_cpr_test(ssl)

test/curlholder_tests.cpp

@@ -0,0 +1,20 @@
+#include <gtest/gtest.h>
+
+#include <utility>
+
+#include "cpr/curlholder.h"
+
+// Check if there is a double free in curl holder after move.
+// To reproduce this, run with address sanitizers enabled.
+// https://github.com/libcpr/cpr/issues/1286
+TEST(CurlholderTests, MoveOperator) {
+    cpr::CurlHolder a;
+    cpr::CurlHolder b;
+    
+    a = std::move(b);
+}
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}