Add code coverage to CI

Signed-off-by: James Hewitt <james.hewitt@uk.ibm.com>

.github/workflows/coverage.yml

@@ -0,0 +1,42 @@
+name: build
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+on:
+  push:
+    branches:
+      - 'main'
+      - 'release/*'
+    tags:
+      - 'v*'
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        go:
+          - 1.20
+          - 1.21
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v3
+      -
+        name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ matrix.go }}
+      -
+        name: Test
+        run: |
+          make coverage
+      -
+        name: Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          directory: ./

.gitignore

@@ -0,0 +1,2 @@
+# Cover profiles
+*.out

Makefile

@@ -0,0 +1,24 @@
+# Project packages.
+PACKAGES=$(shell go list ./... | grep -v /vendor/)
+
+# Flags passed to `go test`
+TESTFLAGS ?= 
+
+.PHONY: all build test coverage
+.DEFAULT: all
+
+all: build
+
+build: ## no binaries to build, so just check compilation suceeds
+	go build ${PACKAGES}
+
+test: ## run tests
+	go test ${TESTFLAGS} ${PACKAGES}
+
+coverage: ## generate coverprofiles from the unit tests
+	rm -f coverage.txt
+	go test ${TESTFLAGS} -cover -coverprofile=cover.out ${PACKAGES}
+
+.PHONY: help
+help:
+	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m\033[0m\n"} /^[a-zA-Z_\/%-]+:.*?##/ { printf "  \033[36m%-27s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)

README.md

@@ -7,6 +7,7 @@ Go library to handle references to container images.
 [![Build Status](https://github.com/distribution/reference/workflows/CI/badge.svg?branch=main&event=push)](https://github.com/distribution/reference/actions?query=workflow%3ACI)
 [![GoDoc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/distribution/reference)
 [![License: Apache-2.0](https://img.shields.io/badge/License-Apache--2.0-blue.svg)](LICENSE)
+[![codecov](https://codecov.io/gh/distribution/reference/branch/main/graph/badge.svg)](https://codecov.io/gh/distribution/reference)
 [![FOSSA Status](https://app.fossa.com/api/projects/custom%2B162%2Fgithub.com%2Fdistribution%2Freference.svg?type=shield)](https://app.fossa.com/projects/custom%2B162%2Fgithub.com%2Fdistribution%2Freference?ref=badge_shield)
 
 This repository contains a library for handling refrences to container images held in container registries. Please see [godoc](https://pkg.go.dev/github.com/distribution/reference) for details.