allow skipping (unreachable) branch coverage only

[akostadinov]

Hello, I would like to be able to skip some unreachable branches but I only see full coverage skipping with nocov.

For example the following code will report the else is never run but it is unreachable:

match = match = /^(\d+)([abc])$/.match(str)
raise unless match
case match[2]
when "a"
...
when "b"
...
when "c"
...
end

Is there another tag or can such be implemented that will only ignore branch coverage?

[tycooon]

You can ignore that implicit branch like this:

case match[2]
when "a"
...
when "b"
...
when "c"
...
else
  :nocov:
  nil
  :nocov:
end

[akostadinov]

Ok, thank you! Somehow not ideal but also I don't see any better way :)

[tycooon]

Yep, you also can actually cover that branch if you want 👍

[akostadinov]

What do you mean with cover? raise or cover as in tests?

[tycooon]

I mean you may write a unit test where that normally unreachable branch is tested (and it may contain something like raise "Invalid something whatever".

[akostadinov]

I can't reach it because it will not match the RE and will fail earlier than the case statement.

[sudeeptarlekar]

Is syntax for skipping branch correct??

:nocov:
nil
:nocov:

or am I missing something here?

[sudeeptarlekar]

My bad, its

# :nocov:
nil
# :nocov:

[win93]

Any thoughts of allowing # :nocov: as a suffix to a line?

case match[2]
...
else
  nil # :nocov:
end

or even

case match[2]
...
else nil # :nocov:
end

This would be great to have because then there's not extra lines of code just to mark a case as unreachable. If interested, I could spend some time developing a patch for this.

[tycooon]

@win93 there is a PR for that #1068.
Unfortunately, maintainers have been mostly inactive lately.