Overview

Slim is a Go tool that lists only those packages affected by source control changes. In other words, if you are working on a ginormous monorepo, this ought to speed up your build times tremendously without sacrificing proper testing techniques.

Install

$ go get -u github.com/kevin-cantwell/slim/cmd/...

Usage

Usage of slim:
  slim [-debug] [-diff <diff>] [<packages>]
Options:
  -debug
      Verbose output.
  -diff string
      The git commit pattern to diff by. E.g.: 'HEAD', or '<commit>...<commit>' (default "HEAD")

Where <packages> is the standard go packages pattern (see go help list).

Algorithm

At a high-level: Slim evaluates the diff flag as a git diff and discovers packages in the current project that might be impacted by each file change.

The output can be passed directly into go test:

$ go test $(slim ./...)

At a low level:

• Any path with a change to *_test.go or *.go files will be listed (not including files prefixed with "." or "_").
• Any package with buildable go files which depends on the above will be listed.
• If changed file resides inside a testdata directory, all the parent directories that contain *_test.go files will be listed. This is a conservative assumption that a test may depend on testdata directories adjacent to or beneath it.