feat: Support more natural languages for the features. (#120)

Co-authored-by: Dmitrii Malinovskii <you@example.com>

.gitignore

@@ -8,6 +8,7 @@ bin
 
 # IDE
 .vscode
+.idea
 
 # Test binary, built with `go test -c`
 *.test

README.md

@@ -204,6 +204,13 @@ Usage of gherkingen [FEATURE_FILE]:
         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
@@ -251,7 +258,7 @@ create a pull request for supporting templates for them. For this:
 3. Check: `make lint check.generate test`.
 4. Commit&Push, create a PR.
 
-## Language support
+## 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`.

internal/app/app.feature

@@ -1,55 +1,56 @@
 Feature: Application command line tool
+
   Scenario Outline: User wants to generate the output in given format
     When <format> is given
     And  <feature> is provided
     Then the output should be generated
     Examples:
-    | <feature>        | <format> | <assertion> |
-    | app.feature      | go       | does        |
-    | app.feature      | json     | does        |
-    | app.feature      | raw      | does        |
-    | app.feature      | invalid  | does not    |
-    | notfound.feature | raw      | does not    |
+      | <feature>        | <format> | <assertion> |
+      | app.feature      | go       | does        |
+      | app.feature      | json     | does        |
+      | app.feature      | raw      | does        |
+      | app.feature      | invalid  | does not    |
+      | notfound.feature | raw      | does not    |
 
   Scenario Outline: User wants to see usage information
     When <flag> is provided
     Then usage should be printed
     Examples:
-    | <flag> |
-    | --help |
+      | <flag> |
+      | --help |
 
   Scenario Outline: User wants to list built-in templates
     When <flag> is provided
     Then templates should be printed
     Examples:
-    | <flag> |
-    | --list |
+      | <flag> |
+      | --list |
 
   Scenario Outline: User wants to use custom template
     When <template> is provided
     And  <feature> is provided
     Then the output should be generated
     Examples:
-    | <feature>   | <template>                      |
-    | app.feature | ../assets/std.simple.v1.go.tmpl |
-    | app.feature | @/std.simple.v1.go.tmpl         |
-  
+      | <feature>   | <template>                      |
+      | app.feature | ../assets/std.simple.v1.go.tmpl |
+      | app.feature | @/std.simple.v1.go.tmpl         |
+
   Scenario Outline: User wants to set custom package
     When <package> is provided
     Then the output should contain <package>
     Examples:
-    | <package>     |
-    | app_test      |
-    | example_test  |
-  
+      | <package>    |
+      | app_test     |
+      | example_test |
+
   Scenario Outline: User wants to generate a permanent json output
     When -format is json
     And -permanent-ids is <TheSameIDs>
     Then calling generation twice will produce the same output <TheSameIDs>
     Examples:
-    | <TheSameIDs> |
-    | true         |
-    | false        |
+      | <TheSameIDs> |
+      | true         |
+      | false        |
 
   Scenario: User provides an invalid flag
     When flag -invalid is provided
@@ -59,17 +60,17 @@ Feature: Application command line tool
     When <flag> is provided
     Then version is printed
     Examples:
-    | <flag>    |
-    | --version |
-    | -version  |
+      | <flag>    |
+      | --version |
+      | -version  |
 
   Scenario Outline: User specifies a file, but the file is not found
     When inexistent <template> is provided
     And  <feature> is provided
     Then the user receives an error
     Examples:
-    | <feature>   | <template> |
-    | app.feature | not_found  |
+      | <feature>   | <template> |
+      | app.feature | not_found  |
 
   Scenario: User wants to run tests in parallel
     When `scenario.feature` is given
@@ -79,3 +80,41 @@ Feature: Application command line tool
     When `-disable-go-parallel` is provided
     And `scenario.feature` is given
     Then generated code doesn't contain `t.Parallel()`
+
+  Scenario Outline: User wants to generate the output for a feature written in a specific natural language
+    When the <language> is given
+    And the <feature> is provided
+    Then the output should be generated
+    Examples:
+      | <language>  | <feature>                                      | assertion |
+      | en          | ../generator/examples/simple.feature           | does      |
+      | en-pirate   | ../generator/examples/simple.en-pirate.feature | does      |
+      | unsupported | app.feature                                    | does not  |
+
+  Scenario Outline: User wants to see all supported natural languages
+    When the <flag> is provided
+    Then the list of supported natural languages should be printed
+    Examples:
+      | <flag>      |
+      | -languages  |
+      | --languages |
+
+  Scenario: User wants to see consistent supported natural languages output
+    When the user lists supported natural languages several times
+    Then the output is the same
+
+  Scenario Outline: User wants to be able to specify the natural language of a feature in its file name
+    When the <language> is specified by the flag
+    And the <feature> is given
+    Then the output should be generated
+    Examples:
+      | <language> | <feature>                                  | assertion |
+      | en-pirate  | ./testdata/pirate.feature                  | does      |
+      |            | ./testdata/pirate.feature                  | does not  |
+      |            | ./testdata/pirate.sample.en-pirate.feature | does      |
+      | wrong      | ./testdata/pirate.sample.en-pirate.feature | does not  |
+      | en         | ./testdata/english.feature                 | does      |
+      |            | ./testdata/english.feature                 | does      |
+      |            | ./testdata/english.sample.en.feature       | does      |
+      | wrong      | ./testdata/english.sample.en.feature       | does not  |
+      |            | app.feature                                | does      |

internal/app/app.go

@@ -4,22 +4,27 @@ import (
 	"flag"
 	"io"
 	"math/rand"
+	"slices"
 	"strings"
 	"time"
 
-	"github.com/hedhyw/gherkingen/v4/internal/model"
-
+	gherkin "github.com/cucumber/gherkin/go/v28"
 	"github.com/google/uuid"
+
+	"github.com/hedhyw/gherkingen/v4/internal/model"
 )
 
 const (
 	internalPathPrefix       = "@/"
 	defaultTemplate          = "std.simple.v1.go.tmpl"
 	defaultDisableGoParallel = false
 	defaultOutputFormat      = model.FormatAutoDetect
+	defaultLanguage          = gherkin.DefaultDialect
 )
 
 // Run the application.
+//
+//nolint:cyclop // Looks fine to me.
 func Run(arguments []string, out io.Writer, version string) (err error) {
 	flagSet := flag.NewFlagSet(flag.CommandLine.Name(), flag.ContinueOnError)
 	flagSet.SetOutput(out)
@@ -69,6 +74,20 @@ func Run(arguments []string, out io.Writer, version string) (err error) {
 		false,
 		"print version",
 	)
+	language := flagSet.String(
+		"language",
+		defaultLanguage,
+		"Specifies the natural language used to describe the feature.\n"+
+			"This flag is optional if language information is included in the feature file name, or if the feature is written in English.\n"+
+			"The file name should be formatted as follows: <description>.<language_hint>.feature if language hint is included, "+
+			"or <description>.feature if it is not.\n"+
+			"When provided, the 'language' flag takes precedence over the language hint from the file name.",
+	)
+	listLanguages := flagSet.Bool(
+		"languages",
+		false,
+		"list supported natural feature languages",
+	)
 	if err = flagSet.Parse(arguments); err != nil {
 		return err
 	}
@@ -86,11 +105,19 @@ func Run(arguments []string, out io.Writer, version string) (err error) {
 		inputFile = flagSet.Args()[0]
 	}
 
+	if !slices.Contains(arguments, "-language") {
+		if hint := tryFromFileName(inputFile); hint != "" {
+			*language = hint
+		}
+	}
+
 	switch {
 	case *versionCmd:
 		return runVersion(out, version)
 	case *listCmd:
 		return runListTemplates(out)
+	case *listLanguages:
+		return runListFeatureLanguages(out)
 	case *helpCmd, inputFile == "":
 		return runHelp(flagSet)
 	default:
@@ -102,6 +129,7 @@ func Run(arguments []string, out io.Writer, version string) (err error) {
 			PackageName:  *packageName,
 			GoParallel:   !(*disableGoParallel),
 			GenerateUUID: newUUIDRandomGenerator(seed),
+			Language:     *language,
 		})
 	}
 }

internal/app/app_test.go

@@ -1,13 +1,15 @@
+//nolint:goconst // These are auto generated tests.
 package app_test
 
 import (
 	"bytes"
 	"testing"
 
-	"github.com/hedhyw/gherkingen/v4/internal/app"
-
+	gherkin "github.com/cucumber/gherkin/go/v28"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/hedhyw/gherkingen/v4/internal/app"
 )
 
 const testVersion = "0.0.1"
@@ -121,6 +123,126 @@ func TestApplicationCommandLineTool(t *testing.T) {
 			})
 		}
 	})
+
+	t.Run("User wants to generate the output for a feature written in a specific natural language", func(t *testing.T) {
+		t.Parallel()
+
+		type testCase struct {
+			Language  string `field:"<language>"`
+			Feature   string `field:"<feature>"`
+			Assertion string `field:"assertion"`
+		}
+
+		testCases := map[string]testCase{
+			"en_../generator/examples/simple.feature_does":                  {"en", "../generator/examples/simple.feature", "does"},
+			"en-pirate_../generator/examples/simple.en-pirate.feature_does": {"en-pirate", "../generator/examples/simple.en-pirate.feature", "does"},
+			"unsupported_app.feature_does_not":                              {"unsupported", "app.feature", "does not"},
+		}
+
+		for name, testCase := range testCases {
+			t.Run(name, func(t *testing.T) {
+				t.Parallel()
+
+				// When the <language> is given.
+				arguments := []string{
+					"-language",
+					testCase.Language,
+				}
+
+				// And the <feature> is provided.
+				arguments = append(arguments, testCase.Feature)
+
+				// Then the output should be generated.
+				runApp(t, arguments, testCase.Assertion == "does")
+			})
+		}
+	})
+
+	t.Run("User wants to see all supported natural languages", func(t *testing.T) {
+		t.Parallel()
+
+		type testCase struct {
+			Flag string `field:"<flag>"`
+		}
+
+		testCases := map[string]testCase{
+			"-languages":  {"-languages"},
+			"--languages": {"--languages"},
+		}
+
+		for name, testCase := range testCases {
+			t.Run(name, func(t *testing.T) {
+				t.Parallel()
+
+				// When the <flag> is provided.
+				arguments := []string{testCase.Flag}
+
+				// Then the list of supported natural languages should be printed.
+				out := runApp(t, arguments, true)
+
+				dialectProvider := gherkin.DialectsBuiltin()
+				dialect := dialectProvider.GetDialect(gherkin.DefaultDialect)
+
+				assert.Contains(t, out, dialect.Name)
+				assert.Contains(t, out, dialect.Language)
+				assert.Contains(t, out, dialect.Native)
+			})
+		}
+	})
+
+	t.Run("User wants to see consistent supported natural languages output", func(t *testing.T) {
+		t.Parallel()
+
+		// When the user lists supported natural languages several times.
+		arguments := []string{"-languages"}
+
+		out1 := runApp(t, arguments, true)
+		out2 := runApp(t, arguments, true)
+
+		// Then the output is the same.
+		assert.Equal(t, out1, out2)
+	})
+
+	t.Run("User wants to be able to specify the natural language of a feature in its file name", func(t *testing.T) {
+		t.Parallel()
+
+		type testCase struct {
+			Language  string `field:"<language>"`
+			Feature   string `field:"<feature>"`
+			Assertion string `field:"assertion"`
+		}
+
+		testCases := map[string]testCase{
+			"en-pirate_./testdata/pirate.feature_does":                  {"en-pirate", "./testdata/pirate.feature", "does"},
+			"_./testdata/pirate.feature_does_not":                       {"", "./testdata/pirate.feature", "does not"},
+			"_./testdata/pirate.sample.en-pirate.feature_does":          {"", "./testdata/pirate.sample.en-pirate.feature", "does"},
+			"wrong_./testdata/pirate.sample.en-pirate.feature_does_not": {"wrong", "./testdata/pirate.sample.en-pirate.feature", "does not"},
+			"en_./testdata/english.feature_does":                        {"en", "./testdata/english.feature", "does"},
+			"_./testdata/english.feature_does":                          {"", "./testdata/english.feature", "does"},
+			"_./testdata/english.sample.en.feature_does":                {"", "./testdata/english.sample.en.feature", "does"},
+			"wrong_./testdata/english.sample.en.feature_does_not":       {"wrong", "./testdata/english.sample.en.feature", "does not"},
+			"_app.feature_does":                                         {"", "app.feature", "does"},
+		}
+
+		for name, testCase := range testCases {
+			t.Run(name, func(t *testing.T) {
+				t.Parallel()
+
+				var arguments []string
+
+				// When the <language> is specified by the flag.
+				if testCase.Language != "" {
+					arguments = append(arguments, "-language", testCase.Language)
+				}
+
+				// And the <feature> is given.
+				arguments = append(arguments, testCase.Feature)
+
+				// Then the output should be generated.
+				runApp(t, arguments, testCase.Assertion == "does")
+			})
+		}
+	})
 }
 
 func TestApplicationCommandLineToolCustom(t *testing.T) {