`test/test__helper.rb` starts SimpleCov with no `minimum_coverage`, so the build accepts arbitrarily low coverage

[edmoffo]

test/test__helper.rb:8-12 runs:

require 'simplecov'
SimpleCov.start

require 'simplecov-cobertura'
SimpleCov.formatter = SimpleCov::Formatter::CoberturaFormatter

The block sets up coverage measurement and the Cobertura output formatter but never calls SimpleCov.minimum_coverage, SimpleCov.minimum_coverage_by_file, or SimpleCov.refuse_coverage_drop. SimpleCov defaults to reporting only; it does not fail the build when coverage falls below a threshold because there is no threshold configured.

The consequence is that bundle exec rake reports a green build even when a contributor lands a change that drops line coverage close to zero. Future swarms generated from this template inherit the same blind spot: the Cobertura XML lands under coverage/, but nothing in CI reads it back and gates merges on it.

A minimal fix is one line after SimpleCov.start, for example SimpleCov.minimum_coverage 95, set to the level the current suite already meets. A second line, SimpleCov.refuse_coverage_drop, prevents slow erosion when contributors add code without adding tests.

[edmoffo]

@yegor256 happy to clarify or propose a concrete threshold value based on a quick local coverage run.