Let's report actionable minimum numbers for Branch Coverage

[corsonknowles]

Currently, simplecov is rounding up when delivering branch coverage results. If we then set minimum branch coverage to the reported amount, the next spec run will fail.

Example:

Line Coverage: 100.0% (3486 / 3486)
Branch Coverage: 98.2% (763 / 777)
Running RuboCop...
Inspecting 281 files

763 / 777 = 0.98198198198

So the ideal number for the report would be 98.19, i.e. the floor of the 2nd decimal place.

Running specs with 98.19 will pass, as expected.

gem list simplecov

*** LOCAL GEMS ***

simplecov (0.22.0)
simplecov-html (0.13.1, 0.12.3)
simplecov_json_formatter (0.1.4)

Reproduction steps:
Set up Rubocop RSpec

• https://github.com/rubocop/rubocop-rspec

Run bundle exec rake

Check out this branch if you want to reproduce with the exact coverage metrics described here:

• Complete branch coverage for more files rubocop/rubocop-rspec#1990

[corsonknowles]

I think we can accomplish this by changing:
https://github.com/simplecov-ruby/simplecov/blob/b6c2d4208a5fa395ce09d7e1d3b074f680ee29b0/lib/simplecov/formatter/simple_formatter.rb#L17C75-L17C80
output << "#{file.filename} (coverage: #{file.covered_percent.round(2)}%)\n"

to use .floor(2) rather than round(2)

[corsonknowles]

Digging around (haha, yes pun intended) a little bit, it looks like almost all other occurrences of this issue were handled here:

• Stricter coverage percentage computation to ensure 100% coverage means exactly 100% #773

[corsonknowles]

Hi Tobias!
Can we get your help with this?
@PragTob

[corsonknowles]

Here's a potential fix:

• Follow the repo convention to use floor instead of round to provide actionable coverage metrics #1116

(regardless of whether it fixes this specific issue, it moves us closer to consistency and having actionable numbers to set min coverage with)