hel

README

Hel

Hel is the norse goddess that rules over Helheim, where the souls of those who did not die in battle go.

This little tool is similar; it generates (hopefully simple) mocks of Go interface types and stores them in helheim_test.go (by default).

Motivation

There are plenty of mock generators out there, but:

1. I felt like messing more with Go's ast package.
2. The mock generators that I know about seem to generate complicated mocks, and often generate their mocks as exported types in a separate package.

• A side note on exported mocks: Exporting mocks seems to, on some projects, encourage the idea that an interface defines everything that a type is capable of. In Go, I find that to be a bad practice; local interfaces should be defined as functionality that the local logic needs, and concrete types implementing said functionality should be passed in. This keeps interfaces very small, which keeps mocks (mostly) simple.

Installation

Pre-reqs

Hel shells out to goimports to set up its import clause(s), so you'll need that installed somewhere in your PATH.

Go Get

Hel is go-gettable

Without Modules

I put a lot of effort into backward compatibility on the master branch. If you're avoiding the go modules tire fire and still using normal GOPATH, you can just use the base repository URL.

go get git.sr.ht/~nelsam/hel

WARNING: if you're using modules, this will pull down v1, which is very old. With modules, if the major version isn't included in the import path, then it will pull down v1. Unless there is no v1, in which case it will pull down master.

Using Modules

If you want to completely lock down hel's version, I have versioned branches from which I create semantically versioned tags. Master is periodically merged in to the latest major version branch and a new tag is released.

go get git.sr.ht/~nelsam/hel/v3

Usage

At its simplest, you can just run hel without any options in the directory you want to generate mocks for. Mocks will be saved in a file called helheim_test.go by default.

See hel -h or hel --help for command line options. Most flags allow multiple calls (e.g. -t ".*Foo" -t ".*Bar").

Go Generate

Adding comments for go generate to use Hel is relatively flexible. Some examples:

In a file (e.g. generate.go) in the root of your project:

//go:generate hel --package ./...

The above command would find all exported interface types in the project and generate mocks in helheim_test.go in each of the packages it finds interfaces to mock.

In a file (e.g. generate.go) in each package you want mocks to be generated for:

//go:generate hel

The above command would generate mocks for all exported types in the current package in helheim_test.go

Above each interface type you want a mock for

//go:generate hel --type Foo --output mock_foo_test.go

type Foo interface {
   Foo() string
}

The above command would generate a mock for the Foo type in mock_foo_test.go

Documentation

Overview

Package main implements the hel command.