Make World.reset also reset example group counts

[agis]

If we don't reset example group counts in custom runners that run from
the same process, example metadata end up being published with incorrect
scoped IDs.

World#example_group_counts_by_spec_file is merely added for testability.

Fixes #2721

[JonRowe]

Can we get a spec for this? Something along the lines of creating a world, adding some examples and showing that the hash is not 0 unless reset?

[agis]

@JonRowe I was instead thinking something on a higher-level, like:

require "rspec/core"
require "stringio"

# RSpec.describe "foo" do
#   it "bar" do
#     expect(true).to be true
#   end
# end

def truncate_timings(output)
	output.gsub(/Finished in.*\n/, '')
end

expected_output = StringIO.new
actual_output = StringIO.new

opts = RSpec::Core::ConfigurationOptions.new(["./foo_spec.rb[1:1]"])
RSpec::Core::Runner.new(opts).run(nil, $stderr)
expected_output = truncate_timings(expected_output.string)

RSpec.clear_examples

opts = RSpec::Core::ConfigurationOptions.new(["./foo_spec.rb[1:1]"])
# without the fix, the following invocation executes 0 examples
RSpec::Core::Runner.new(opts).run(nil, $stderr)
actual_output = truncate_timings(actual_output.string)

# expected_output == actual_output

Thoughts? I think this way it's more apparent what the fix is about.

If that seems good, could you point me to some similar specs from RSpec's codebase which I can follow as examples?

That said, I don't really like the part with comparing the outputs, perhaps there's a more future-proof way of doing this? The point is to verify that the correct example ran once in each invocation.

[JonRowe]

We have a bunch of integration specs in spec/integration might be worth putting something together like you describe, I would also like a unit level spec that says that this count is reset after reset too though..

[agis]

We have a bunch of integration specs in spec/integration might be worth putting something together like you describe, I would also like a unit level spec that says that this count is reset after reset too though..

We have a bunch of integration specs in spec/integration might be worth putting something together like you describe, I would also like a unit level spec that says that this count is reset after reset too though..

@JonRowe Added unit and integration specs (see #2723 (comment) though).

[JonRowe]

Great work, some stylistic changes and a fix for your aruba issue.

[JonRowe]

Great! I'll merge on green, thanks so much! 💜 ❤️ 💚 💛 🧡