Coverage

You ran the suite. It is green. The question left is whether those tests actually walked the code you think they did.

echoc test --coverage

That instruments the tests and prints one line after the last one finishes:

coverage 81.2% lines, 64.0% branches -> ecobuild/coverage

A compile without the flag is unchanged. run and build do not take it: covering a binary with no test id is a different product.

What is counted

Functions the tests call. Not the test bodies themselves, not helpers that live only in a #[target: test] source list, and not the standard library unless you pass --coverage-stdlib.

Line coverage is "did this source line run". Branch coverage is which way control went: then / else, a loop body, a guard else, a match arm, the right side of && / ||, the fallback of ??.

A generic body is compiled once per instance, but it is still one piece of source. The summary counts a line, and a branch edge at its column, as covered when any instance ran it, so List<string> never being shown does not mark show as missed when List<int32> was. map.json keeps the counters per instance for anyone who wants that split.

Only what can run is counted. while (true) has no edge out of the loop, and code after a loop that only return leaves gets no counter, so a function like that can still reach 100%.

A child that asserts still leaves its counts.

The files

ecobuild/coverage/map.json names the counters. coverage/tests/*.ecocov is one file per test. The summary merges them. Keep the per-test files if you want to know which test hit which line.

Next

Testing