gherkingen

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: User wants to see usage information
    When flag <flag> is provided
    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) {
	f := bdd.NewFeature(t, "Application command line tool")

	f.Scenario("User wants to see usage information", func(t *testing.T, f *bdd.Feature) {
		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},
		}

		f.TestCases(testCases, func(t *testing.T, f *bdd.Feature, tc testCase) {
			f.When("flag <flag> is provided", func() {

			})
			f.Then("usage should be printed <printed>", func() {

			})
			f.And("exit status should be <exit_status>", func() {

			})
		})
	})
}

Then on failure next logs will be printed:

Feature: Application command line tool
	Scenario: User wants to see usage information
		# TestCase: {Flag:-invalid ExitStatus:1 Printed:false}
		When flag -invalid is provided
		Then usage should be printed false
		And exit status should be 1

Example implementation:

f.TestCases(testCases, func(t *testing.T, f *bdd.Feature, tc testCase) {
	var exitStatus int
	arguments := []string{}

	f.When("flag <flag> is provided", func() {
		arguments = append(arguments, tc.Flag)
	})
	f.Then("usage should be printed <printed>", func() {
		var output string
		output, exitStatus = runApp(t, arguments)
		assert.Equal(t, tc.Printed, strings.Contains(output, "usage"))
	})
	f.And("exit status should be <exit_status>", func() {
		assert.Equal(t, tc.ExitStatus, exitStatus)
	})
})

More advanced example

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

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/cmd/gherkingen@latest

Source

git clone git@github.com:hedhyw/gherkingen.git
cd gherkingen
go install cmd/gherkingen/main.go

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]:
  -format string
        output format: json, go, raw (default "go")
  -help
        print usage
  -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.struct.v1.go.tmpl")

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/ \
	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.struct.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.

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:

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 }}.

License

See LICENSE.