feat: add error handling

pipeline.go

@@ -4,6 +4,6 @@ type Pipeline[K any] struct {
 	stepDelegate StepDelegate[K]
 }
 
-func (t Pipeline[K]) Execute(context K) {
-	t.stepDelegate(context)
+func (t Pipeline[K]) Execute(context K) error {
+	return t.stepDelegate(context)
 }

pipeline_builder.go

@@ -5,7 +5,9 @@ type Builder[K any] struct {
 }
 
 func (t Builder[K]) Build() Pipeline[K] {
-	var step StepDelegate[K] = func(context K) {}
+	var step StepDelegate[K] = func(context K) error {
+		return nil
+	}
 	for i := len(t.steps) - 1; i >= 0; i-- {
 		step = t.steps[i](step)
 	}
@@ -16,8 +18,8 @@ func (t Builder[K]) Build() Pipeline[K] {
 
 func (t Builder[K]) UsePipelineStep(step Step[K]) Builder[K] {
 	t.steps = append(t.steps, func(next StepDelegate[K]) StepDelegate[K] {
-		return func(context K) {
-			step.Execute(context, next)
+		return func(context K) error {
+			return step.Execute(context, next)
 		}
 	})
 	return t

pipeline_error_test.go

@@ -0,0 +1,30 @@
+package pipeline_test
+
+import (
+	"fmt"
+	"github.com/mhmtszr/pipeline"
+	"testing"
+)
+
+type (
+	SuccessStep struct{}
+	ErrorStep   struct{}
+)
+
+func (s SuccessStep) Execute(context *int, next func(context *int) error) error {
+	return next(context)
+}
+
+func (e ErrorStep) Execute(context *int, next func(context *int) error) error {
+	return fmt.Errorf("errorstep error")
+}
+
+func TestErrorPipeline(t *testing.T) {
+	p := pipeline.Builder[*int]{}.UsePipelineStep(SuccessStep{}).UsePipelineStep(ErrorStep{}).Build()
+	nm := 3
+	err := p.Execute(&nm)
+	if err != nil && err.Error() == "errorstep error" {
+		return
+	}
+	t.Errorf("error step should return error")
+}

pipeline_step.go

@@ -1,7 +1,7 @@
 package pipeline
 
-type StepDelegate[K any] func(context K)
+type StepDelegate[K any] func(context K) error
 
 type Step[K any] interface {
-	Execute(context K, next func(context K))
+	Execute(context K, next func(context K) error) error
 }

pipeline_test.go

@@ -1,6 +1,7 @@
-package pipeline
+package pipeline_test
 
 import (
+	"github.com/mhmtszr/pipeline"
 	"testing"
 )
 
@@ -9,18 +10,18 @@ type (
 	Add    struct{}
 )
 
-func (s Square) Execute(context *int, next func(context *int)) {
+func (s Square) Execute(context *int, next func(context *int) error) error {
 	*context = (*context) * (*context)
-	next(context)
+	return next(context)
 }
 
-func (a Add) Execute(context *int, next func(context *int)) {
+func (a Add) Execute(context *int, next func(context *int) error) error {
 	*context = (*context) + (*context)
-	next(context)
+	return next(context)
 }
 
 func TestPipeline(t *testing.T) {
-	p := Builder[*int]{}.UsePipelineStep(Square{}).UsePipelineStep(Add{}).Build()
+	p := pipeline.Builder[*int]{}.UsePipelineStep(Square{}).UsePipelineStep(Add{}).Build()
 	nm := 3
 	want := 18
 	p.Execute(&nm)