I not infrequently find that I want to use both --grep and --invert --grep in the same test command: inclusively filter to a set of tests and exclude a subset of those too.

Just to put this out there for discussion, what if we:

• created --invert-grep or --grep-not, which would be equivalent to the current --invert --grep
• optionally remove --invert for clarity in a semver major (we could see how much confusion it causes first)
• until it's removed consider it an error to use --invert with the new --invert-grep/--grep-not
• allow both --grep and --invert-grep/--grep-not in the same command, filtering to tests that satisfy both
• optionally allow multiple --grep or --invert-grep/--grep-not, filtering to tests that satisfy all (this allows more flexible filtering than --grep "one thing.*another thing" as it does not care about the order; ORing is not significantly more powerful than | in a --grep in contrast and makes almost no sense for --invert-grep/--grep-not*, so we don't really need it but if there's any use for it a --or-greps option to change from ANDing to ORing would do -- I guess some of this explanation also applies even if multiple of the same type aren't allowed, just one of each type)

* You'd only exclude tests that contain the --invert-grep/--grep-not and do not also contain the --grep, which is awfully broad... conceivably this could mean "use --grep to make exceptions to the tests filtered out by --invert-grep/--grep-not", but this seems less likely to be a common use case. Something similar goes for ORing multiple --invert-grep/--grep-not.