Implement a unit test case for parsing trans output

trans/trans.go

@@ -7,29 +7,30 @@ import (
 	"log"
 )
 
-type Translator interface {
-	Translate() []string
+
+type Translation struct {
+	job TransJob
+	Executor func(TransJob) ([]byte, error)
 }
 
-type transJob struct {
+type TransJob struct {
 	word string
 	fromLang string
 	toLang string
 }
 
-func New(word, fromLang, toLang string) Translator {
-	return transJob{word: word, fromLang: fromLang, toLang: toLang}
-}
-
-func (tj transJob) Translate() []string {
-	outBytes, err := tj.execTrans()
-	if err != nil {
-		log.Fatalf("Failed to execute command 'trans': %v", err)
+func New(word, fromLang, toLang string) Translation {
+	return Translation{
+		job: TransJob{
+			word: word,
+			fromLang: fromLang,
+			toLang: toLang,
+		},
+		Executor: executeTransShell,
 	}
-	return uniqueSlice(parseTransOutput(string(outBytes)))
 }
 
-func (tj transJob) execTrans() ([]byte, error) {
+func executeTransShell(tj TransJob) ([]byte, error) {
 	config := []string{
 		"-no-ansi",
 		"-show-original", "n",
@@ -43,6 +44,14 @@ func (tj transJob) execTrans() ([]byte, error) {
 	return exec.Command("trans", config...).Output()
 }
 
+func (t Translation) Translate() []string {
+	outBytes, err := t.Executor(t.job)
+	if err != nil {
+		log.Fatalf("Failed to execute command 'trans': %v", err)
+	}
+	return uniqueSlice(parseTransOutput(string(outBytes)))
+}
+
 func parseTransOutput(out string) []string {
 	outLines := strings.Split(out, "\n")
 	translation := outLines[0]

trans/trans_test.go

@@ -0,0 +1,39 @@
+package trans_test
+
+import (
+	"testing"
+	"."
+	"reflect"
+)
+
+
+type testData struct {
+	job []string
+	transOutput []byte
+	expectedResults []string
+}
+
+func TestTranslation(t *testing.T) {
+	cases := []testData{
+		testData{
+			[]string{"actuator", "en", "hu"},
+			[]byte(`működtető
+
+actuator
+	működtető, beavatkozó, hajtómű, aktuátor, hajtás
+`),
+			[]string{"működtető", "beavatkozó", "hajtómű", "aktuátor", "hajtás"},
+		},
+	}
+
+	for _, data := range cases {
+		j := trans.New(data.job[0], data.job[1], data.job[2])
+		j.Executor = func(tj trans.TransJob) ([]byte, error) {
+			return data.transOutput, nil
+		}
+		r := j.Translate()
+		if (!reflect.DeepEqual(r, data.expectedResults)) {
+			t.Error()
+		}
+	}
+}