Run your tests using Go test

Prerequisites

Complete the Build your Go image section of this guide.

Overview

Testing is an essential part of modern software development. Testing can mean a lot of things to different development teams. There are unit tests, integration tests and end-to-end testing. In this guide you take a look at running your unit tests in Docker when building.

For this section, use the docker-gs-ping project that you cloned in Build your Go image.

Run tests when building

To run your tests when building, you need to add a test stage to the Dockerfile.multistage. The Dockerfile.multistage in the sample application's repository already has the following content:

# syntax=docker/dockerfile:1

# Build the application from source
FROM golang:1.19 AS build-stage

WORKDIR /app

COPY go.mod go.sum ./
RUN go mod download

COPY *.go ./

RUN CGO_ENABLED=0 GOOS=linux go build -o /docker-gs-ping

# Run the tests in the container
FROM build-stage AS run-test-stage
RUN go test -v ./...

# Deploy the application binary into a lean image
FROM gcr.io/distroless/base-debian11 AS build-release-stage

WORKDIR /

COPY --from=build-stage /docker-gs-ping /docker-gs-ping

EXPOSE 8080

USER nonroot:nonroot

ENTRYPOINT ["/docker-gs-ping"]

Run the following command to build an image using the run-test-stage stage as the target and view the test results. Include --progress plain to view the build output, --no-cache to ensure the tests always run, and --target run-test-stage to target the test stage.

$ docker build -f Dockerfile.multistage -t docker-gs-ping-test --progress plain --no-cache --target run-test-stage .

You should see output containing the following.

#13 [run-test-stage 1/1] RUN go test -v ./...
#13 4.915 === RUN   TestIntMinBasic
#13 4.915 --- PASS: TestIntMinBasic (0.00s)
#13 4.915 === RUN   TestIntMinTableDriven
#13 4.915 === RUN   TestIntMinTableDriven/0,1
#13 4.915 === RUN   TestIntMinTableDriven/1,0
#13 4.915 === RUN   TestIntMinTableDriven/2,-2
#13 4.915 === RUN   TestIntMinTableDriven/0,-1
#13 4.915 === RUN   TestIntMinTableDriven/-1,0
#13 4.915 --- PASS: TestIntMinTableDriven (0.00s)
#13 4.915     --- PASS: TestIntMinTableDriven/0,1 (0.00s)
#13 4.915     --- PASS: TestIntMinTableDriven/1,0 (0.00s)
#13 4.915     --- PASS: TestIntMinTableDriven/2,-2 (0.00s)
#13 4.915     --- PASS: TestIntMinTableDriven/0,-1 (0.00s)
#13 4.915     --- PASS: TestIntMinTableDriven/-1,0 (0.00s)
#13 4.915 PASS

To learn more about building and running tests, see the Build with Docker guide.

Next steps

In this section, you learned how to run tests when building your image. Next, you’ll learn how to set up a CI/CD pipeline using GitHub Actions.

Configure CI/CD