Return error on invalid pipeline type

pipeline.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/fs"
 	"log"
@@ -65,7 +66,7 @@ type Step struct {
 	Type StepType
 }
 
-func (s Step) Translate() IExecutableStep {
+func (s Step) Translate() (IExecutableStep, error) {
 	var step IExecutableStep
 	switch s.GetType() {
 	case TypeResizeImageStep:
@@ -75,10 +76,10 @@ func (s Step) Translate() IExecutableStep {
 	}
 
 	if step == nil {
-		panic("invalid step")
+		return nil, errors.New("invalid type")
 	}
 
-	return step
+	return step, nil
 }
 
 func (s Step) GetType() StepType {

pipeline_test.go

@@ -78,6 +78,10 @@ func TestTranslateStep(t *testing.T) {
 		assert.Equal(t, 1, len(steps), "Output steps should contain one element")
 		assert.Equal(t, "resize image", steps[0].GetName())
 		assert.Equal(t, TypeResizeImageStep, steps[0].GetType())
+
+		translated, err := steps[0].Translate()
+		assert.Equal(t, err, nil)
+		assert.IsType(t, ResizeImageStep{}, translated)
 	})
 }
 
@@ -89,7 +93,7 @@ func TestInvalidStepType(t *testing.T) {
 		"steps": [
 			{
 				"name": "resize image",
-				"type": 0
+				"type": 99999
 			}
 		]
 	}`
@@ -101,6 +105,10 @@ func TestInvalidStepType(t *testing.T) {
 
 		assert.Equal(t, 1, len(steps), "Output steps should contain one element")
 		assert.Equal(t, "resize image", steps[0].GetName())
-		assert.Equal(t, TypeResizeImageStep, steps[0].GetType())
+		assert.Equal(t, StepType(99999), steps[0].GetType())
+
+		translated, err := steps[0].Translate()
+		assert.EqualError(t, err, "invalid type")
+		assert.Nil(t, translated)
 	})
 }