Add unit test for DEBUG_LOCKORDER code

src/test/sync_tests.cpp

@@ -0,0 +1,41 @@
+// Copyright (c) 2012-2017 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <sync.h>
+#include <test/test_bitcoin.h>
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(sync_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(potential_deadlock_detected)
+{
+    #ifdef DEBUG_LOCKORDER
+    bool prev = g_debug_lockorder_abort;
+    g_debug_lockorder_abort = false;
+    #endif
+
+    CCriticalSection mutex1, mutex2;
+    {
+        LOCK2(mutex1, mutex2);
+    }
+    bool error_thrown = false;
+    try {
+        LOCK2(mutex2, mutex1);
+    } catch (const std::logic_error& e) {
+        BOOST_CHECK_EQUAL(e.what(), "potential deadlock detected");
+        error_thrown = true;
+    }
+    #ifdef DEBUG_LOCKORDER
+    BOOST_CHECK(error_thrown);
+    #else
+    BOOST_CHECK(!error_thrown);
+    #endif
+
+    #ifdef DEBUG_LOCKORDER
+    g_debug_lockorder_abort = prev;
+    #endif
+}
+
+BOOST_AUTO_TEST_SUITE_END()