gotestsum

gotestsum runs tests using go test -json, prints formatted test output, and a summary of the test run. It is designed to work well for both local development, and for automation like CI. gotestsum is used by some of the most popular Go projects.

Install

Download a binary from releases, or build from source with go install gotest.tools/gotestsum@latest. To run without installing use go run gotest.tools/gotestsum@latest.

Documentation

Core features

• Change the test output format, from compact to verbose with color highlighting.
• Print a summary of the test run after running all the tests.
• Use any go test flag, run a script with --raw-command, or run a compiled test binary.

CI and Automation

• --junitfile - write a JUnit XML file for integration with CI systems.
• --jsonfile - write all the test2json input received by gotestsum to a file. The file can be used as input to gotestsum tool slowest, or as a way to store the full verbose output of tests when less verbose output is printed to stdout using a compact --format.
• --rerun-fails - run failed (possibly flaky) tests again to avoid re-running the entire suite. Re-running individual tests can save significant time when working with flaky test suites.

Local Development

• --watch - every time a .go file is saved run the tests for the package that changed.
• --post-run-command - run a command after the tests, can be used for desktop notification of the test run.
• gotestsum tool slowest - find the slowest tests, or automatically update the source code of the slowest tests to add a conditional t.Skip statements. This statement allows you to skip the slowest tests using gotestsum -- -short ./....

Output Format

The --format flag or GOTESTSUM_FORMAT environment variable set the format that is used to print the test names, and possibly test output, as the tests run. Most outputs use color to highlight pass, fail, or skip.

The --format-hivis flag changes the icons used by pkgname formats to higher visiblity unicode characters.

Commonly used formats (see --help for a full list):

• dots - print a character for each test.
• pkgname (default) - print a line for each package.
• testname - print a line for each test and package.
• standard-quiet - the standard go test format.
• standard-verbose - the standard go test -v format.

Have an idea for a new format? Please share it on github!

Demo

A demonstration of three --format options.

^Source

Summary

Following the formatted output is a summary of the test run. The summary includes:

• The test output, and elapsed time, for any test that fails or is skipped.

• The build errors for any package that fails to build.

• A DONE line with a count of tests run, tests skipped, tests failed, package build errors, and the elapsed time including time to build.

  DONE 101 tests[, 3 skipped][, 2 failures][, 1 error] in 0.103s
  

To hide parts of the summary use --hide-summary section.

Example: hide skipped tests in the summary

gotestsum --hide-summary=skipped

Example: hide everything except the DONE line

gotestsum --hide-summary=skipped,failed,errors,output
# or
gotestsum --hide-summary=all

Example: hide test output in the summary, only print names of failed and skipped tests and errors

gotestsum --hide-summary=output

JUnit XML output

When the --junitfile flag or GOTESTSUM_JUNITFILE environment variable are set to a file path, gotestsum will write a test report, in JUnit XML format, to the file. This file can be used to integrate with CI systems.

gotestsum --junitfile unit-tests.xml

If the package names in the testsuite.name or testcase.classname fields do not work with your CI system these values can be customized using the --junitfile-testsuite-name, or --junitfile-testcase-classname flags. These flags accept the following values:

• short - the base name of the package (the single term specified by the package statement).
• relative - a package path relative to the root of the repository
• full - the full package path (default)

Note: If Go is not installed, or the go binary is not in PATH, the GOVERSION environment variable can be set to remove the "failed to lookup go version for junit xml" warning.

JSON file output

When the --jsonfile flag or GOTESTSUM_JSONFILE environment variable are set to a file path, gotestsum will write a line-delimited JSON file with all the test2json output that was written by go test -json. This file can be used to compare test runs, or find flaky tests.

gotestsum --jsonfile test-output.log

Post Run Command

The --post-run-command flag may be used to execute a command after the test run has completed. The binary will be run with the following environment variables set:

GOTESTSUM_FORMAT        # gotestsum format (ex: short)
GOTESTSUM_JSONFILE      # path to the jsonfile, empty if no file path was given
GOTESTSUM_JUNITFILE     # path to the junit.xml file, empty if no file path was given
TESTS_ERRORS            # number of errors
TESTS_FAILED            # number of failed tests
TESTS_SKIPPED           # number of skipped tests
TESTS_TOTAL             # number of tests run

To get more details about the test run, such as failure messages or the full list of failed tests, run gotestsum with either a --jsonfile or --junitfile and parse the file from the post-run-command. The gotestsum/testjson package may be used to parse the JSON file output.

Example: desktop notifications

First install the example notification command with go get gotest.tools/gotestsum/contrib/notify. The command will be downloaded to $GOPATH/bin as notify. Note that this example notify command only works on macOS with terminal-notifer installed.

gotestsum --post-run-command notify

Example: command with flags

Possitional arguments or command line flags can be passed to the --post-run-command by quoting the whole command.

gotestsum --post-run-command "notify me --date"

Example: printing slowest tests

The post-run command can be combined with other gotestsum commands and tools to provide a more detailed summary. This example uses gotestsum tool slowest to print the slowest 10 tests after the summary.

gotestsum \
  --jsonfile tmp.json.log \
  --post-run-command "bash -c '
    echo; echo Slowest tests;
    gotestsum tool slowest --num 10 --jsonfile tmp.json.log'"

Re-running failed tests

When the --rerun-fails flag is set, gotestsum will re-run any failed tests. The tests will be re-run until each passes once, or the number of attempts exceeds the maximum attempts. Maximum attempts defaults to 2, and can be changed with --rerun-fails=n.

To avoid re-running tests when there are real failures, the re-run will be skipped when there are too many test failures. By default this value is 10, and can be changed with --rerun-fails-max-failures=n.

Note that using --rerun-fails may require the use of other flags, depending on how you specify args to go test:

• when used with --raw-command the re-run will pass additional arguments to the command. The first arg is a -test.run flag with a regex that matches the test to re-run, and second is the name of a go package. These additional args can be passed to go test, or a test binary.

• when used with any go test args (anything after -- on the command line), the list of packages to test must be specified as a space separated list using the --packages arg.

  Example

  gotestsum --rerun-fails --packages="./..." -- -count=2
  

• if any of the go test args should be passed to the test binary, instead of go test itself, the -args flag must be used to separate the two groups of arguments. -args is a special flag that is understood by go test to indicate that any following args should be passed directly to the test binary.

  Example

  gotestsum --rerun-fails --packages="./..." -- -count=2 -args -update-golden
  

Custom go test command

By default gotestsum runs tests using the command go test -json ./.... You can change the command with positional arguments after a --. You can change just the test directory value (which defaults to ./...) by setting the TEST_DIRECTORY environment variable.

You can use --debug to echo the command before it is run.

Example: set build tags

gotestsum -- -tags=integration ./...

Example: run tests in a single package

gotestsum -- ./io/http

Example: enable coverage

gotestsum -- -coverprofile=cover.out ./...

Example: run a script instead of go test

gotestsum --raw-command -- ./scripts/run_tests.sh

Note: when using --raw-command, the script must follow a few rules about stdout and stderr output:

• The stdout produced by the script must only contain the test2json output, or gotestsum will fail. If it isn't possible to change the script to avoid non-JSON output, you can use --ignore-non-json-output-lines (added in version 1.7.0) to ignore non-JSON lines and write them to gotestsum's stderr instead.
• Any stderr produced by the script will be considered an error (this behaviour is necessary because package build errors are only reported by writting to stderr, not the test2json stdout). Any stderr produced by tests is not considered an error (it will be in the test2json stdout).

Example: accept intput from stdin

cat out.json | gotestsum --raw-command -- cat

Example: run tests with profiling enabled

Using a profile.sh script like this:

#!/usr/bin/env bash
set -eu

for pkg in $(go list "$@"); do
    dir="$(go list -f '{{ .Dir }}' $pkg)"
    go test -json -cpuprofile="$dir/cpu.profile" "$pkg"
done

You can run:

gotestsum --raw-command ./profile.sh ./...

Example: using TEST_DIRECTORY

TEST_DIRECTORY=./io/http gotestsum

Executing a compiled test binary

gotestsum supports executing a compiled test binary (created with go test -c) by running it as a custom command.

The -json flag is handled by go test itself, it is not available when using a compiled test binary, so go tool test2json must be used to get the output that gotestsum expects.

Example: running ./binary.test

gotestsum --raw-command -- go tool test2json -t -p pkgname ./binary.test -test.v

pkgname is the name of the package being tested, it will show up in the test output. ./binary.test is the path to the compiled test binary. The -test.v must be included so that go tool test2json receives all the output.

To execute a test binary without installing Go, see running without go.

Finding and skipping slow tests

gotestsum tool slowest reads test2json output, from a file or stdin, and prints the names and elapsed time of slow tests. The tests are sorted from slowest to fastest.

gotestsum tool slowest can also rewrite the source of tests slower than the threshold, making it possible to optionally skip them.

The test2json output can be created with gotestsum --jsonfile or go test -json.

See gotestsum tool slowest --help.

Example: printing a list of tests slower than 500 milliseconds

$ gotestsum --format dots --jsonfile json.log
[.]····↷··↷·
$ gotestsum tool slowest --jsonfile json.log --threshold 500ms
gotest.tools/example TestSomething 1.34s
gotest.tools/example TestSomethingElse 810ms

Example: skipping slow tests with go test --short

Any test slower than 200 milliseconds will be modified to add:

if testing.Short() {
    t.Skip("too slow for testing.Short")
}

go test -json -short ./... | gotestsum tool slowest --skip-stmt "testing.Short" --threshold 200ms

Use git diff to see the file changes. The next time tests are run using --short all the slow tests will be skipped.

Run tests when a file is saved

When the --watch flag is set, gotestsum will watch directories using file system notifications. When a Go file in one of those directories is modified, gotestsum will run the tests for the package that contains the changed file. By default all directories under the current directory with at least one .go file will be watched. Use the --packages flag to specify a different list.

If --watch is used with a command line that includes the name of one or more packages as command line arguments (ex: gotestsum --watch -- ./... or gotestsum --watch -- ./extrapkg), the tests in those packages will also be run when any file changes.

With the --watch-chdir flag, gotestsum will change the working directory to the directory with the modified file before running tests. Changing the directory is primarily useful when the project contains multiple Go modules. Without this flag, go test will refuse to run tests for any package outside of the main Go module.

While in watch mode, pressing some keys will perform an action:

• r will run tests for the previous event. Added in version 1.6.1.
• u will run tests for the previous event, with the -update flag added. Many golden packages use this flag to automatically update expected values of tests. Added in version 1.8.1.
• d will run tests for the previous event using dlv test, allowing you to debug a test failure using delve. A breakpoint will automatically be added at the first line of any tests which failed in the previous run. Additional breakpoints can be added with runtime.Breakpoint or by using the delve command prompt. Added in version 1.6.1.
• a will run tests for all packages, by using ./... as the package selector. Added in version 1.7.0.
• l will scan the directory list again, and if there are any new directories which contain a file with a .go extension, they will be added to the watch list. Added in version 1.7.0.

Note that delve must be installed in order to use debug (d).

Example: run tests for a package when any file in that package is saved

gotestsum --watch --format testname

Who uses gotestsum?

The projects below use (or have used) gotestsum.

• kubernetes
• moby (aka Docker)
• etcd
• hashicorp/vault
• hashicorp/consul
• prometheus
• minikube
• influxdb
• pulumi
• grafana/k6
• grafana/loki
• telegraf
• containerd
• linkerd2
• elastic/go-elasticsearch
• microsoft/hcsshim
• pingcap/tidb
• dex
• coder
• docker/cli

Please open a GitHub issue or pull request to add or remove projects from this list.

Development

Pull requests and bug reports are welcome! Please open an issue first for any big changes.

Thanks

This package is heavily influenced by the pytest test runner for python.