Add coverage target in Makefile for coverage reporting

Signed-off-by: Joffrey F <joffrey@docker.com>

Author: shin-

.gitignore

@@ -1,4 +1,5 @@
 *.tar.gz
 *.dockerapp
 _build/
+codecoverage/*.out
 !examples/simple/*.dockerapp

Makefile

@@ -84,6 +84,15 @@ unit-test:
 clean:
 	rm -Rf ./_build docker-app-*.tar.gz
 
+coverage-bin:
+	$(GO_TEST) -coverpkg="./..." -c -tags testrunmain -o _build/$(BIN_NAME).cov
+
+coverage: coverage-bin
+	DOCKERAPP_BINARY=../codecoverage/coverage-bin $(GO_TEST) -v ./e2e
+	$(GO_TEST) -cover -test.coverprofile=codecoverage/unit.out $(shell go list ./... | grep -vE '/vendor/|/e2e')
+	gocovmerge codecoverage/*.out > codecoverage/all.out
+	go tool cover -func codecoverage/all.out
+
 ##########################
 # Continuous Integration #
 ##########################

codecoverage/coverage-bin

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# This script is a proxy that injects the required test flags and strips out test output
+# It allows us to use a coverage-enabled binary for e2e tests
+
+../_build/docker-app.cov $* -test.v -test.coverprofile=../codecoverage/e2e.out | \
+grep -vE '^PASS$' | grep -vE '^coverage: [0-9]+\.[0-9]+% of statements in .+$' | grep -v '^=== RUN   TestRunMain$'

main_test.go

@@ -0,0 +1,9 @@
+// +build testrunmain
+
+package main
+
+import "testing"
+
+func TestRunMain(t *testing.T) {
+	main()
+}