circle.yml

version: 2
jobs:
  build:
    working_directory: /go/src/github.com/your_company/your_app
    docker:
      - image: circleci/golang:1.10.0
    environment:
      - GOCACHE: "/tmp/go/cache"
    steps:

...

      - restore_cache:
          keys:
              - build-cache-{{ .Branch }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
          paths:
              - /tmp/go/cache
      - run:
          name: test
          command: |
            mkdir -p $GOCACHE
            go build -v
            go test -p 6 -race ./...
      - save_cache:
          key: build-cache-{{ .Branch }}-{{ .Environment.CIRCLE_BUILD_NUM }}
          paths:
              - /tmp/go/cache