depstubber

depstubber

This is a tool that generates type-correct stubs for dependencies, for use in testing. It is particularly useful for testing static analysis applications, where including library source code may be undesirable. It was written and is currently used for testing CodeQL Go.

The general usage pattern if vendoring is desired will look something like:

PATH="$PATH:$GOPATH/bin"
GO111MODULES=off go get github.com/github/depstubber
GO111MODULES=off go install github.com/github/depstubber # Only needed for Go 1.18 and above
go mod tidy # required to generate go.sum
# generate a vendor/module.txt for the go 1.24 vendor consistency check
depstubber -write_module_txt
# Create stubs of Type1, Type2, SomeFunc, and SomeVariable. They are separated by a space
# because values must be treated differently from types in the implementation of depstubber.
depstubber -vendor github.com/my/package Type1,Type2 SomeFunc,SomeVariable

The last line can be executed using Go's built in generate subcommand, by adding a comment to any relevant Go file that looks like this:

//go:generate depstubber -vendor github.com/my/package Type1,Type2 SomeFunc,SomeVariable

Then, run go generate <package>, where <package> is the package containing the file the comment was added to. This will automatically run the depstubber command.

Limitations:

• It is limited to a single package at a time.
• There is no way to automatically stub all exports.
• It does not generate memory-compatible types, as unexported types are skipped.
• There is no way to automatically detect exports used in a program.
• There is no way to specify specific methods on a type; all methods are automatically stubbed.
• It cannot currently distinguish between type aliases. This is a limitation of the reflect package.

Please feel free to submit a pull request for any of the above, or with any other improvements. See CONTRIBUTING.md for more information.

For information about what improvements may be in progress, see issues.

To build, simply run go build with Go 1.14 or higher.

This project contains a significant amount of code copied from the GoMock project, as well as from the Go standard library. The mock code has been adapted to generate stub versions of requested exported fields instead of generating a mock implementation of an interface. The licenses for both these codebases can be found in the NOTICE file.

It is licensed under Apache-2.0. For more information, see the LICENSE file.