Coverage and CI Gates

Coverage in a go.work Repo

Meridian is not a single-module Go repository. The root go.work file wires together five modules: libs/platform, apps/gateway, apps/identity-service, apps/community-service, and apps/billing-service. That matters for CI. A naive go test ./... from the repository root does not express the desired contract clearly enough, because the gate must be explicit about which modules are covered and how their results roll up into one merge signal.

What Should Be Gated Now

This keeps the signal honest. An empty internal/domain/domain.go should compile, but it should not distort the coverage conversation. By contrast, libs/platform/config, logging, errors, response, and tenancy are reusable building blocks with stable behavior, so they deserve a real floor immediately.

A Workspace-Aware Script

#!/usr/bin/env bash
set -euo pipefail

coverage_min="${COVERAGE_MIN:-75}"
packages=(
  ./libs/platform/...
  ./apps/gateway/...
  ./apps/identity-service/...
  ./apps/community-service/...
  ./apps/billing-service/...
)

go test -covermode=atomic -coverpkg=./libs/platform/... -coverprofile=coverage.out "${packages[@]}"
total=$(go tool cover -func=coverage.out | awk '/total:/ {gsub("%", "", $3); print $3}')

awk -v total="$total" -v minimum="$coverage_min" 'BEGIN {
  if ((total + 0) < (minimum + 0)) {
    printf("coverage %.1f%% is below required %.1f%%
", total, minimum)
    exit 1
  }
}'

The initial floor can stay moderate because the business surface is still small. Once identity-service owns tenants and memberships, or once billing-service adds invoice generation and payment reconciliation, the policy can evolve toward per-module thresholds or a ratchet that prevents coverage from falling in the touched package set.

CI Jobs Beyond Coverage

name: ci

    on:
      pull_request:
      push:
        branches: [main]

    jobs:
      test:
        runs-on: ubuntu-latest
        steps:
          - uses: actions/checkout@v4
          - uses: actions/setup-go@v5
            with:
              go-version-file: go.work
          - name: Run workspace tests
            run: make test
          - name: Enforce minimum coverage
            env:
              COVERAGE_MIN: 75
            run: ./scripts/check-coverage.sh

      vet:
        runs-on: ubuntu-latest
        steps:
          - uses: actions/checkout@v4
          - uses: actions/setup-go@v5
            with:
              go-version-file: go.work
          - run: make vet

Coverage is only one gate. vet catches static mistakes; later race-detector jobs matter once Redis-backed caches or billing workers introduce concurrency; Newman smoke tests matter once the gateway exposes more than /healthz. The lesson is sequencing: add gates when the corresponding failure mode becomes possible, not years before.

The Decision

• Coverage is enforced against the code that actually exists today: libs/platform and the per-service config packages.
• The gate is workspace-aware because Meridian is a go.work repository, not a single-module binary.
• Empty placeholder packages compile, but they do not justify inflated coverage requirements.
• Additional CI jobs are added as real failure modes appear: repositories, concurrency, and external HTTP contracts.