A test runner already has a --durations option to print durations.
However, this isn't entirely satisfactory.
When there are many tests, this produces output spam which makes it hard
to find the test failure output. Nevertheless, it is helpful to be
informed of tests which are unusually slow.
Therefore, introduce a new option --min-duration that causes all
durations above a certain threshold to be printed. This allows slow
tests to be visible without mentioning every test.
There are some examples on issue #850 of using this feature, but they
are not easily found from the documentation. Adding them here as an
example makes them more findable and ensures they keep working if the
API changes.
The two changes are
`catch_matchers_templates` -> `catch_matchers_templated` and
`catch_matchers_generic` -> `catch_matchers_predicate`. The former
is mostly cosmetic, but the second was previously significantly
misleading, and as the library is now to be consumed by including
specific headers, this needed to be fixed.
`SizeIs` can accept both `size_t` and a matcher. In the first case,
it checks whether the size of the range is equal to specified size.
In the second case, it checks whether the provided matcher accepts
the size of the range.
In general, for Catch2 v3 we are making virtual types `final`,
unless they were explicitly designed to be derived-from.
`ListeningReporter` is definitely not designed to be derived-from.
This commit also forbids composing lvalues of composed matchers, as
per previous deprecation notice. I do not expect this to be contentious
in practice, because there was a bug in that usage for years, and
nobody complained.
Given that in the 2 or so years that matchers are thing nobody complained,
it seems that people do not actually write this sort of code, and the
possibility will be removed in v3. However, to avoid correctness bugs,
we will have to support this weird code in v2.
Now that Catch2 is a proper library, we can always build the full
library (comparatively minor slowdown) and the user can avoid
including benchmarking headers to avoid the compilation slowdown.
Now that the recommended distribution and usage method is proper
library, users can just avoid including the matcher headers to get
basically the same effect.
