Compiled bitcoin-0.18.0.tar.gz from https://bitcoin.org/bin/bitcoin-core-0.18.0/ on Ubuntu 18.04.2 LTS (using [this](http://Bitkoins.nl/maken.txt) (simple) bash script). The compilation went well (had to add doxygen to suppress a warning message). When running the test: `test_bitcoin` in `bitcoin-0.18.0/src/test/`, I get the following error messages (multiple times):

`Error: Specified -walletdir "/tmp/test_bitcoin/1556861148_943311758/tempdir/path_does_not_exist" does not exist`

and

`Error: Specified -walletdir "/tmp/test_bitcoin/1556861730_643733972/tempdir/not_a_directory.dat" is not a directory`

and

`Error: Specified -walletdir "wallets" is a relative path`

Note that at the end it still says: `*** No errors detected`

{
    SetWalletDir(m_walletdir_path_cases["default"]);
    bool result = m_chain_client->verify();
    BOOST_CHECK(result == true);
    fs::path walletdir = gArgs.GetArg("-walletdir", "");
    fs::path expected_path = fs::canonical(m_walletdir_path_cases["default"]);
    BOOST_CHECK(walletdir == expected_path);
}
BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_custom)
{
    SetWalletDir(m_walletdir_path_cases["custom"]);
    bool result = m_chain_client->verify();
    BOOST_CHECK(result == true);
    fs::path walletdir = gArgs.GetArg("-walletdir", "");
    fs::path expected_path = fs::canonical(m_walletdir_path_cases["custom"]);
    BOOST_CHECK(walletdir == expected_path);
}
BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_does_not_exist)
{
    SetWalletDir(m_walletdir_path_cases["nonexistent"]);
    bool result = m_chain_client->verify();
    BOOST_CHECK(result == false);
}
BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_is_not_directory)
{
    SetWalletDir(m_walletdir_path_cases["file"]);
    bool result = m_chain_client->verify();
    BOOST_CHECK(result == false);
}
BOOST_AUTO_TEST_CASE(walletinit_verify_walletdir_is_not_relative)