SimpleCov "Line coverage is below the expected minimum" in CI

By Kaveh Alemi·Latchkey

SimpleCov enforces minimum_coverage at the end of the test run. When line (or branch) coverage is below the set minimum, it prints the shortfall and sets a non-zero exit status, failing the CI job.

What this error means

After RSpec/Minitest finishes, SimpleCov prints "SimpleCov failed with exit 2 due to a coverage related error" and "Line coverage (72.5%) is below the expected minimum coverage (80.00%)."

Coverage report generated for RSpec to /app/coverage. 72.5% covered.
Line coverage (72.5%) is below the expected minimum coverage (80.00%).
SimpleCov failed with exit 2 due to a coverage related error.

Common causes

Coverage fell below minimum_coverage

New untested code lowered line or branch coverage under the value configured in the SimpleCov block.

Parallel or multi-suite runs not merged

Split test suites each write partial results; without merging, the measured percentage is lower than the true total and trips the gate.

How to fix it

Add tests or set a realistic minimum

1. Open coverage/index.html to find the uncovered files and lines.
2. Add tests for the gaps.
3. If the bar is too high for now, set minimum_coverage to the honest current level and raise it over time.

# spec/spec_helper.rb
require 'simplecov'
SimpleCov.start do
  minimum_coverage line: 80, branch: 70
end

Merge results from split suites

Use a shared command_name per suite and let SimpleCov merge results so the total is computed across all of them.

SimpleCov.start do
  command_name "Job#{ENV['CI_NODE_INDEX']}"
end

How to prevent it

• Run the suite with SimpleCov locally before pushing.
• Merge coverage from parallel jobs before evaluating the minimum.
• Raise minimum_coverage incrementally as coverage improves.

Frequently asked questions

Related guides

References

• GitHub Actions documentation