test: Allow testing of check failures

This allows specific tests to mock the check behavior to consistently
use exceptions instead of aborts for intentionally failing checks in all
build configurations.

src/test/util_check_tests.cpp

@@ -0,0 +1,33 @@
+// Copyright (c) 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 <util/check.h>
+
+#include <boost/test/unit_test.hpp>
+#include <test/util/setup_common.h>
+
+BOOST_AUTO_TEST_SUITE(util_check_tests)
+
+BOOST_AUTO_TEST_CASE(check_pass)
+{
+    Assume(true);
+    Assert(true);
+    CHECK_NONFATAL(true);
+}
+
+BOOST_AUTO_TEST_CASE(check_fail)
+{
+    // Disable aborts for easier testing here
+    test_only_CheckFailuresAreExceptionsNotAborts mock_checks{};
+
+    if constexpr (G_ABORT_ON_FAILED_ASSUME) {
+        BOOST_CHECK_EXCEPTION(Assume(false), NonFatalCheckError, HasReason{"Internal bug detected: false"});
+    } else {
+        BOOST_CHECK_NO_THROW(Assume(false));
+    }
+    BOOST_CHECK_EXCEPTION(Assert(false), NonFatalCheckError, HasReason{"Internal bug detected: false"});
+    BOOST_CHECK_EXCEPTION(CHECK_NONFATAL(false), NonFatalCheckError, HasReason{"Internal bug detected: false"});
+}
+
+BOOST_AUTO_TEST_SUITE_END()