Go/Godog Overview

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Introduction to Go/Godog BDD testing

This guide provides Go-specific implementation details for the BDD and testing approach described in Three-Layer Testing.

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What This Project Uses

This project uses:

• Go for production code and unit tests
• Godog for executing Gherkin specifications
• Go test framework for unit and integration tests
• Build tags for test level isolation

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Why Go for BDD?

Advantages

Performance: Go's compiled nature makes tests fast and efficient.

Simplicity: Go's simple syntax and minimal abstraction make tests easy to understand.

Tooling: Excellent tooling support with go test, coverage analysis, and profiling.

Concurrency: Built-in concurrency support for parallel test execution.

Standard Library: Rich standard library reduces external dependencies.

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Why Godog?

Godog is the Go implementation of Cucumber, enabling BDD with Gherkin syntax.

Key Characteristics

Native Go Integration: Works seamlessly with go test framework.

Gherkin Support: Full support for Feature, Rule, Scenario, and Examples.

Table Tests: Natural mapping from Gherkin examples to Go table-driven tests.

Parallel Execution: Built-in support for concurrent scenario execution.

Flexible Formatting: Multiple output formats (pretty, progress, JSON, JUnit).

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Quick Start

1. Install Godog

go get github.com/cucumber/godog/cmd/godog@latest

2. Create a Feature File

Location: specs/<module>/<feature>/specification.feature

@cli @critical
Feature: cli_init-project

  As a developer
  I want to initialize a CLI project
  So that I can quickly start development

  Rule: Creates project directory structure

    @ov
    Scenario: Initialize in empty directory
      Given I am in an empty folder
      When I run "r2r init"
      Then a file named "r2r.yaml" should be created

3. Implement Step Definitions

Location: src/<module>/tests/steps_test.go

package tests

import (
    "github.com/cucumber/godog"
)

func InitializeScenario(ctx *godog.ScenarioContext) {
    ctx.Step(`^I am in an empty folder$`, iAmInAnEmptyFolder)
    ctx.Step(`^I run "([^"]*)"$`, iRun)
    ctx.Step(`^a file named "([^"]*)" should be created$`, aFileNamedShouldBeCreated)
}

func iAmInAnEmptyFolder() error {
    // Setup empty directory
    tmpDir := os.TempDir()
    os.Chdir(tmpDir)
    return nil
}

func iRun(command string) error {
    // Execute command
    cmd := exec.Command("sh", "-c", command)
    output, err := cmd.CombinedOutput()
    testContext.lastOutput = string(output)
    testContext.lastError = err
    return nil
}

func aFileNamedShouldBeCreated(filename string) error {
    // Assert file exists
    if _, err := os.Stat(filename); os.IsNotExist(err) {
        return fmt.Errorf("file %s does not exist", filename)
    }
    return nil
}

4. Run Tests

# Run all scenarios
godog run

# Run with pretty output
godog run --format=pretty

# Run specific scenarios
godog run --tags=@ov

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Next Steps

• File Organization - Learn how to structure your Go test files
• Test Levels - Understand L0-L4 test isolation with build tags
• Step Definitions - Write effective step definitions
• Best Practices - Follow Go testing best practices

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