The functions in cql_assertions.hh are very convenient, but have one
frustrating drawback: When you have many of those assertions in one
test, it's very hard to know *which* of the similar assertions failed.
The problem is that an error often looks like this:
unknown location(0): fatal error: in "test_many_columns":
std::runtime_error: Expected 2 row(s) but got 0
tests/cql_assertions.cc(131): last checkpoint
Which of the many similar checks in "test_many_columns" failed? Note the
unhelpful "unknown location" and also the "last checkpoint" points to code
in cql_assertions.cc, not in the actual test, so it is useless.
The root cause of these problems is that the Boost macros use the C
preprocessor __FILE__ and __LINE__, which in actual C++ functions like
is_rows() remembers its location, instead of the caller. Fixing this will
not be simple. But this patch has a much simpler solution - fixing the
"last checkpoint". What ruins the last checkpoint is the use of BOOST_REQUIRE
inside the cql_assertions.cc is_rows() - when that succeeds, it records
the location inside cql_assertions.cc (!) as the last success.
If we just replace BOOST_REQUIRE by our own test (just like in the rest of
the cql_assertions.cc code), this code will not override the last checkpoint.
The user can see the last real successful BOOST_REQUIRE, or use
BOOST_TEST_PASSPOINT() to set his own checkpoints between different parts of
the same test.
After this patch, and with adding BOOST_TEST_PASSPOINT() calls between
different parts of my test, the failure above now looks like:
unknown location(0): fatal error: in "test_many_columns":
std::runtime_error: Expected 2 row(s) but got 0
tests/secondary_index_test.cc(299): last checkpoint
The "last checkpoint" now shows me exactly where my failing check was.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20180501152638.26238-1-nyh@scylladb.com>
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