Bundle certifier into docker image

**What**
- Create a docker image that pre-compiles the certifier tests so that
  the tests are more portable

Signed-off-by: Lucas Roesler <[email protected]>

.travis.yml

@@ -51,3 +51,5 @@ jobs:
         - arkade install openfaas --basic-auth=false
         - kubectl rollout status -n openfaas deploy/gateway -w
       script: make test-kubernetes
+    - name: build
+      script: make build

Dockerfile

@@ -0,0 +1,29 @@
+ARG goversion=1.14
+ARG alpineversion=3.11
+FROM golang:$goversion as builder
+
+
+WORKDIR /app
+
+COPY go.mod .
+COPY go.sum .
+
+RUN go mod download
+
+ENV GO111MODULE=on
+ENV CGO_ENABLED=0
+ARG GOOS=linux
+
+WORKDIR /app
+COPY tests ./tests
+COPY vendor ./vendor
+
+RUN go test -c -o certifier ./tests
+
+FROM alpine:$alpineversion
+
+RUN apk --no-cache --update add ca-certificates
+
+COPY --from=builder /app/certifier /bin/certifier
+
+ENTRYPOINT [ "/bin/certifier" ]

Makefile

@@ -35,3 +35,7 @@ test-swarm: clean-swarm
 
 test-kubernetes: clean-kubernetes
 	time go test -count=1 ./tests -v -gateway=${OPENFAAS_URL} ${.FEATURE_FLAGS} ${.TEST_FLAGS}
+
+
+build:
+	docker build  --cache-from openfaas/certifier:latest  -t openfaas/certifier:latest .