mocks-ut-faq.md

How are the mock files for unit tests organized?

• The name of the mock file generated will be the same as the name of the interface definition.

• Mock files for interfaces defined in the go-controller/vendor directories are located in the go-controller/pkg/testing/mocks directory. The directory structure in the go-controller/pkg/testing/mocks/ closely mimic the directory structure of go-controller/vendor/.

  e.g; a) The Cmd interface defined in the go-controller/vendor/k8s.io/utils/exec.go file has its mock generated in go-controller/pkg/testing/mocks/k8s.io/utils/exec/Cmd.go file

  e.g; b) The Link interface defined in the go-controller/vendor/github.com/vishvananda/netlink/link.go file has its mock generated in go-controller/pkg/testing/mocks/vishvananda/netlink/Link.go file

• Mock files for interfaces defined in the non vendor directories of the project are located in the mocks directory of the same package as where the interface is defined.

  e.g; a) The ExecRunner interface defined in go-controller/pkg/util/ovs.go file has the its mock generated in go-controller/pkg/util/mocks/ExecRunner.go file.

  e.g; b) The SriovNetLibOps interface defined in go-controller/pkg/cni/helper_linux.go file has its mock generated in go-controller/pkg/cni/mocks/SriovNetLibOps.go file.

How are the mocks for interfaces to be consumed by unit tests currently generated?

• The vektra/mockery package from https://github.com/vektra/mockery is leveraged to auto generate mocks for defined interfaces.

• Mocks for interfaces can be generated using vektra/mockery in one of two ways:

  • Using the binaries at https://github.com/vektra/mockery/releases

  • Using the docker image

• Sample commands to generate mocks when using the binary installed on a linux host.

  • Mock for interface SriovNetLibOps defined in the go-controller/pkg/cni/helper_linux.go file when executing the mockery command from dir go-controller/

    mockery --name SriovnetLibOps --dir pkg/cni/ --output pkg/cni/mocks

  • Mock for all interfaces defined in the vendor folder go-controller/vendor/k8s.io/utils/exec when executing the mockery command from dir go-controller/

    mockery --all --dir vendor/k8s.io/utils/exec --output pkg/testing/mocks/k8s.io/utils/exec

• Sample command to generate mocks when using the docker image

  • Mock for interface SriovNetLibOps defined in the go-controller/pkg/cni/helper_linux.go file when running the docker container from dir go-controller/

    docker run -v $PWD:/src -w /src vektra/mockery --name SriovNetLibOps --dir pkg/cni/ --output pkg/cni/mocks

  • Mock for all interfaces defined in the vendor folder go-controller/vendor/k8s.io/utils/exec when running the docker container from dir go-controller/

    docker run -v $PWD:/src -w /src vektra/mockery --all --dir vendor/k8s.io/utils/exec --output pkg/testing/mocks/k8s.io/utils/exec

How to regenerate all existing mocks when interfaces (locally defined or in vendor libraries) are updated?

- Execute the ```go-controller/hack/regenerate_vendor_mocks.sh``` in situations where all existing mocks have to be regenerated.
NOTE: It would take a while(approx 20+ minutes) for all mocks to be regenerated.

Reference links that explain how to use mocks with testify

• https://tutorialedge.net/golang/improving-your-tests-with-testify-go/

• https://techblog.fexcofts.com/2019/09/23/go-and-test-mocking/

• https://gowalker.org/github.com/stretchr/testify/mock

• https://ncona.com/2020/02/using-testify-for-golang-tests/