Deliberately breaking one of the operator<() tests produces less than
ideal diagnostics because it doesn't print the BlockSpecial objects
being compared.
$ ./test_BlockSpecial
...
[ RUN ] BlockSpecialTest.OperatorLessThanTwoEmptyObjects
test_BlockSpecial.cc:362: Failure
Value of: bs1 < bs2
Actual: true
Expected: false
[ FAILED ] BlockSpecialTest.OperatorLessThanTwoEmptyObjects (1 ms)
...
This could be solved by using the Google Test Binary Comparison
assertions, however in the tests for false from (bs1 == bs2) and
(bs1 < bs2) comparisons then operators != and >= would have to be
implemented and the tests changed from:
EXPECT_FALSE( bs1 < bs2 );
to:
EXPECT_GE( bs1, bs2 );
This makes the meaning of the test less than clear. The primary purpose
of the test is to check operator<(), but it is expecting the first
BlockSpecial object to be GE (greater than or equal to) than the second,
which is calling operator>=() which in turn is testing operator<(). For
tests of the operators themselves using Google Test Binary Comparison
assertions obscures what is being tested too much.
Instead provide a custom failure message which prints the BlockSpecial
objects failing the comparison, leaving the test still directly calling
the operator being tested, like this:
EXPECT_FALSE( bs1 < bs2 ) << " Where: bs1 = " << bs1 << "\n"
<< " And: bs2 = " << bs2;
And with a suitable macro this is simplified to:
EXPECT_FALSE( bs1 < bs2 ) << ON_FAILURE_WHERE( bs1, bs2 );
Now the above deliberately broken test produces this output:
$ ./test_BlockSpecial
...
[ RUN ] BlockSpecialTest.OperatorLessThanTwoEmptyObjects
test_BlockSpecial.cc:369: Failure
Value of: bs1 < bs2
Actual: true
Expected: false
Where: bs1 = BlockSpecial{"",0,0}
And: bs2 = BlockSpecial{"",0,0}
[ FAILED ] BlockSpecialTest.OperatorLessThanTwoEmptyObjects (0 ms)
...
Bug 781978 - Add Google Test C++ test framework
Add a specific test for the failure found in bug 771670 and fixed by
commit:
253c4d6416
Fix BlockSpecial comparison (#771670)
Bug 781978 - Add Google Test C++ test framework
So far only includes tests of the construction of BlockSpecial objects
and the interaction with the internal cache used to reduce the number of
stat(2) calls. Tests have been designed to be runable by non-root users
and assume as little as possible about the environment by discovering
used block device names and symbolic link name.
Bug 781978 - Add Google Test C++ test framework
Mike Fleetwood