gherkingen

It's a Behaviour Driven Development (BDD) tests generator for Golang.

It accepts a *.feature Cucumber/Gherkin file and generates a test boilerplate. All that remains is to change the tests a little. The generator supports go generate and go test for generated tests.

The generator is very customizable, it is possible to customize an output for any golang testing framework or even for another language.

What is for?

Simple example

Given feature [reference]:

Feature: Application command line tool
  Scenario Outline: User wants to see usage information
    When the application is started with <flag>
    Then usage should be printed <printed>
    And exit status should be <exit_status>
    Examples:
    | <flag>   | <exit_status> | <printed> |
    | --help   |       0       | true      |
    | -help    |       0       | true      |
    | -invalid |       1       | false     |

Then this generator writes a golang output (gerkingen readme.feature > readme.feature_test.go):

func TestApplicationCommandLineTool(t *testing.T) {
	t.Parallel()

	t.Run("User wants to see usage information", func(t *testing.T) {
		t.Parallel()

		type testCase struct {
			Flag       string `field:"<flag>"`
			ExitStatus int    `field:"<exit_status>"`
			Printed    bool   `field:"<printed>"`
		}

		testCases := map[string]testCase{
			"--help_0_true":    {"--help", 0, true},
			"-help_0_true":     {"-help", 0, true},
			"-invalid_1_false": {"-invalid", 1, false},
		}

		for name, testCase := range testCases {
			testCase := testCase

			t.Run(name, func(t *testing.T) {
				t.Parallel()

				// When the application is started with <flag>.

				// Then usage should be printed <printed>.

				// And exit status should be <exit_status>.

			})
		}
	})
}

Example implementation:

t.Run(name, func(t *testing.T) {
	t.Parallel()

	// When flag <flag> is provided.
	arguments := []string{testCase.Flag}

	// Then usage should be printed <printed>.
	var output string
	output, exitStatus = runApp(t, arguments)
	assert.Equal(t, testCase.Printed, strings.Contains(output, "usage"))

	// And exit status should be <exit_status>.
	assert.Equal(t, testCase.ExitStatus, exitStatus)
})

More advanced example

See internal/app/app.feature and internal/app/app_test.go.

Version 3 changes

1. Simplified template is set by default. In order to use the default template from the previous versions, provide the following flag -template @/std.struct.v1.go.tmpl.
2. All tests will have t.Parallel by default. This behaviour can be disabled by providing the flag -disable-go-parallel.

Version 4 changes

1. Removed template "std.struct.v1.go.tmpl".

Install

Package

Latest DEB and RPM packages are available on the releases page.

MacOS/Linux HomeBrew

# Install the package using HomeBrew.
brew install hedhyw/gherkingen/gherkingen

# Check that the generator is working.
gherkingen -help

Standalone Binary

Download latest archive *.tar.gz for your target platform from the releases page and extract it to /usr/local/bin/gherkingen. Add this path to PATH environment.

Example flow:

# Check the signature of a downloaded archive and the signature in the file task_checksums.txt from the release page.

# Remove old binaries.
rm -rf /usr/local/gherkingen
# Restore folder structure.
mkdir -p /usr/local/gherkingen
# Extract archive to target path.
tar -C /usr/local/gherkingen -xzf DOWNLOAD_ARCHIVE.TAR.GZ

# Add `/usr/local/gherkingen` to PATH environment variable.
export PATH=/usr/local/gherkingen:$PATH
# Check that the generator is working.
gherkingen -help

Go

go install github.com/hedhyw/gherkingen/v4/cmd/gherkingen@latest
# Notice: gherkingen -version will return "unknown" version.

Source

git clone git@github.com:hedhyw/gherkingen.git
cd gherkingen
make build
cp ./bin/gherkingen /usr/local/bin
chmod +x /usr/local/bin

Visual Studio Code extension

The extension for VS-Code that helps to generate Behaviour Driven Development (BDD) boilerplate Golang tests. It uses docker to run gherkingen.

https://marketplace.visualstudio.com/items?itemName=hedhyw.golang-gherkingen&ssr=false#overview

Launch VS Code Quick Open (Ctrl+P or Cmd+P), paste the following command, and press enter: ext install hedhyw.golang-gherkingen.

Usage of the extension (in any .feature file):

• Open the command palette (Ctrl+Shift+P or Cmd+Shift+P) and search for "Go: Generate BDD Golang test".
• Or, click the button "Generate BDD Golang test" in the editor's menu.

Usage

Simple usage

For generating test output, simply run:

gherkingen EXAMPLE.feature

More advanced usage

Generating test output with custom options

gherkingen \
    -format go \
    -template my_template.tmpl \
    EXAMPLE.feature

Listing internal templates

gherkingen -list

Help

gherkingen --help

Usage of gherkingen [FEATURE_FILE]:
  -disable-go-parallel
        disable execution of tests in parallel
  -format string
        output format: autodetect, json, go, raw (default "autodetect")
  -go-parallel
        add parallel mark (deprecated, enabled by default) (default true)
  -help
        print usage
  -language string
        Specifies the natural language used to describe the feature.
        This flag is optional if language information is included in the feature file name, or if the feature is written in English.
        The file name should be formatted as follows: <description>.<language_hint>.feature if language hint is included, or <description>.feature if it is not.
        When provided, the 'language' flag takes precedence over the language hint from the file name. (default "en")
  -languages
        list supported natural feature languages
  -list
        list internal templates
  -package string
        name of the generated package (default "generated_test")
  -permanent-ids
        The same calls to the generator always produces the same output
  -template string
        template file (default "@/std.simple.v1.go.tmpl")
  -version
        print version

Running in docker

Docker image: https://hub.docker.com/r/hedhyw/gherkingen

Running gherkingen in docker, <RELATIVE_PATH_TO_FEATURE_FILE> is a path to a feature file relatively to the current directory.

docker run --rm -it --read-only --network none \
	--volume $PWD:/host/:ro \
	hedhyw/gherkingen:latest \
	-- /host/<RELATIVE_PATH_TO_FEATURE_FILE>

Passing arguments:

# Any command-line tool arguments also can be used.
# Example:
docker run --rm -it --read-only --network none \
	hedhyw/gherkingen:latest -list

Output customization

Custom templates

You can provide your own template, it can be based on internal/assets/std.simple.v1.go.tmpl. In the command-line tool specify the template using -template flag: gherkingen -template example.tmpl raw example.feature

Frameworks support

It is possible to integrate the generator with any BDD-testing fraemwork. Feel free to create a pull request for supporting templates for them. For this:

1. Create a template internal/assets/SOME_NAME.go.tmpl.
2. Add it to the test TestOpenTemplate in the file internal/assets/assets_test.go.
3. Check: make lint check.generate test.
4. Commit&Push, create a PR.

Programming language support

Templates are very customizable, so you can even generate non-golang code. In the command-line tool specify raw format using -format flag and your template using -template flag: gherkingen -format raw -template example.tmpl example.feature.

Creating templates

Useful resources:

Resource	Link
Golang template documentation	text/template
Root template object struct documentation	TemplateData
Example template	std.simple.v1.go.tmpl
Example json representation of a root template object	readme.feature.json

There is a way to return a json representation of the root object TemplateData for your feature, for this run gherkingen -format json <EXAMPLE.feature>.

Any field of the root object can be used directly, example: {{ .PackageName }}.

golangci-lint thelper warning

Exclude the rule thelper for scenarios in the configuration .golangci.yaml:

issues:
  fix: true
  exclude-rules:
    - linters:
        - thelper
      source: "^.*f\\.Scenario.*$"

License

• The library and generator are under MIT Lecense.
• The gopher is under Creative Commons Attribution 3.0 license. It was originally designed by Renée French and redrawed by me.