To install, type goinstall -u github.com/kylelemons/gimmock{,/mock}

NOTE: Not all of the functionality outlined below is implemented. Check out the example/ directory to see what is.

When testing source code with complicated object relationships, it can be difficult to test them independently. Mocking frameworks allow programmers to inject an extra layer of code in between the code under test and the components on which it depends. Gimmock generates mock structures compatible with specific interfaces and allows the programmer to examine calls and specify returns and apply stub methods.

In order for gimmock to work, you have to tell it what mocks it needs to generate. In your _test.go file, you indicate this by commenting a top-level element (usually a function) with a comment of the following form:

//MOCK(<interfaces>)

For example:

import (
  "os"
  "testing"
  "github.com/kylelemons/gimmock"
)

//MOCK(os.Error)
func TestSomething(t *testing.T) {
  defer gimmock.Check(t)
  var err os.Error
  gimmock.Mock(&err).
    ExpectString().AndReturn("test").
    ExpectString().AndReturn("another")
}

If the interface to be mocked is not in the current package, it can be specified in the above os.Error format. The package name, however, must match either the last file segment in its import declaration or the assigned local package name from its import statement. For example:

import somelib "somelib.googlecode.com/hg"

//MOCK(somelib.SomeInterface)
func TestSomething(t *testing.T) {
  defer gimmock.Check(t)

  gimmock.Mock(&err).
    ExpectString().AndReturn("test").
    ExpectString().AndReturn("another")
}

The above is necessary even if somelib is the package name. Additionally, the package must be installed to the GOROOT package directory, not a GOPATH directory. This restriction may be lifted in the future.