Tests_coverage

ccanlint's tests_coverage test gives a score out of 6, based on the total code coverage of running the tests in the test/ subdirectory.

This calculation isn't perfect, since line coverage doesn't mean thorough coverage, nor does it count macros, nor does it mean the tests are actually useful, but it's a useful guide to directing writing of further tests.

The score is 1 for 50% coverage, 2 for 75%, 3 for 87.5%, 4 for 93.75, 5 for 96.875 and 6 for 100%. You can often use the ccan/failtest module to obtain coverage on error paths.