GoMock is a mocking framework for the Go programming language. It integrates well with Go's built-in
testing package, but can be used in other contexts too.
Once you have installed Go, run these commands to install the
gomock package and the
go get github.com/golang/mock/gomock go get github.com/golang/mock/mockgen
After installing, you can use
go doc to get documentation:
go doc github.com/golang/mock/gomock
Alternatively, there is an online reference for the package hosted on GoPkgDoc here.
mockgen has two modes of operation: source and reflect. Source mode generates mock interfaces from a source file. It is enabled by using the -source flag. Other flags that may be useful in this mode are -imports and -aux_files.
mockgen -source=foo.go [other options]
Reflect mode generates mock interfaces by building a program that uses reflection to understand interfaces. It is enabled by passing two non-flag arguments: an import path, and a comma-separated list of symbols.
mockgen database/sql/driver Conn,Driver
mockgen command is used to generate source code for a mock class given a Go source file containing interfaces to be mocked. It supports the following flags:
-source: A file containing interfaces to be mocked.
-destination: A file to which to write the resulting source code. If you don't set this, the code is printed to standard output.
-package: The package to use for the resulting mock class source code. If you don't set this, the package name is
mock_ concatenated with the package of the input file.
-imports: A list of explicit imports that should be used in the resulting source code, specified as a comma-separated list of elements of the form
bar/baz is the package being imported and
foo is the identifier to use for the package in the generated source code.
-aux_files: A list of additional files that should be consulted to resolve e.g. embedded interfaces defined in a different file. This is specified as a comma-separated list of elements of the form
bar/baz.go is the source file and
foo is the package name of that file used by the -source file.
-build_flags: (reflect mode only) Flags passed verbatim to
For an example of the use of
mockgen, see the
sample/ directory. In simple cases, you will need only the
TODO: Brief overview of how to create mock objects and set up expectations, and an example.