102 lines
2.5 KiB
Markdown
102 lines
2.5 KiB
Markdown
 [](https://travis-ci.org/matryer/moq)
|
|
|
|
Interface mocking tool for go generate.
|
|
|
|
By [Mat Ryer](https://twitter.com/matryer) and [David Hernandez](https://github.com/dahernan), with ideas lovingly stolen from [Ernesto Jimenez](https://github.com/ernesto-jimenez).
|
|
|
|
### What is Moq?
|
|
|
|
Moq is a tool that generates a struct from any interface. The struct can be used in test code as a mock of the interface.
|
|
|
|
|
|
### Installing
|
|
|
|
To start using Moq, just run go get:
|
|
```
|
|
$ go get github.com/matryer/moq
|
|
```
|
|
|
|
### Usage
|
|
|
|
```
|
|
moq [flags] destination interface [interface2 [interface3 [...]]]
|
|
-out string
|
|
output file (default stdout)
|
|
-pkg string
|
|
package name (default will infer)
|
|
```
|
|
|
|
In a command line:
|
|
|
|
```
|
|
$ moq -out mocks_test.go . MyInterface
|
|
```
|
|
|
|
In code (for go generate):
|
|
|
|
```go
|
|
package my
|
|
|
|
//go:generate moq -out myinterface_moq_test.go . MyInterface
|
|
|
|
type MyInterface interface {
|
|
Method1() error
|
|
Method2(i int)
|
|
}
|
|
```
|
|
|
|
Then run `go generate` for your package.
|
|
|
|
### How to use it
|
|
|
|
Mocking interfaces is a nice way to write unit tests where you can easily control the behaviour of the mocked object.
|
|
|
|
Moq creates a struct that has a function field for each method, which you can declare in your test code.
|
|
|
|
This this example, Moq generated the `EmailSenderMock` type:
|
|
|
|
```go
|
|
func TestCompleteSignup(t *testing.T) {
|
|
|
|
called := false
|
|
var sentTo string
|
|
|
|
mockedEmailSender = &EmailSenderMock{
|
|
SendFunc: func(to, subject, body string) error {
|
|
called = true
|
|
sentTo = to
|
|
return nil
|
|
},
|
|
}
|
|
|
|
CompleteSignUp("me@email.com", mockedEmailSender)
|
|
|
|
if called == false {
|
|
t.Error("Sender.Send expected")
|
|
}
|
|
if sentTo != "me@email.com" {
|
|
t.Errorf("unexpected recipient: %s", sentTo)
|
|
}
|
|
|
|
}
|
|
|
|
func CompleteSignUp(to string, sender EmailSender) {
|
|
// TODO: this
|
|
}
|
|
```
|
|
|
|
The mocked structure implements the interface, where each method calls the associated function field.
|
|
|
|
## Tips
|
|
|
|
* Keep mocked logic inside the test that is using it
|
|
* Only mock the fields you need - it will panic if a nil function gets called
|
|
* Use closured variables inside your test function to capture details about the calls to the methods
|
|
* Use `go:generate` to invoke the `moq` command
|
|
|
|
## License
|
|
|
|
The Moq project (and all code) is licensed under the [MIT License](LICENSE).
|
|
|
|
The Moq logo was created by [Chris Ryer](http://chrisryer.co.uk) and is licensed under the [Creative Commons Attribution 3.0 License](https://creativecommons.org/licenses/by/3.0/).
|