refactor and organize code

internal/gperr/builder_test.go

@@ -0,0 +1,55 @@
+package gperr_test
+
+import (
+	"context"
+	"errors"
+	"io"
+	"testing"
+
+	. "github.com/yusing/go-proxy/internal/gperr"
+	. "github.com/yusing/go-proxy/internal/utils/testing"
+)
+
+func TestBuilderEmpty(t *testing.T) {
+	eb := NewBuilder("foo")
+	ExpectTrue(t, errors.Is(eb.Error(), nil))
+	ExpectFalse(t, eb.HasError())
+}
+
+func TestBuilderAddNil(t *testing.T) {
+	eb := NewBuilder("foo")
+	var err Error
+	for range 3 {
+		eb.Add(nil)
+	}
+	for range 3 {
+		eb.Add(err)
+	}
+	eb.AddRange(nil, nil, err)
+	ExpectFalse(t, eb.HasError())
+	ExpectTrue(t, eb.Error() == nil)
+}
+
+func TestBuilderIs(t *testing.T) {
+	eb := NewBuilder("foo")
+	eb.Add(context.Canceled)
+	eb.Add(io.ErrShortBuffer)
+	ExpectTrue(t, eb.HasError())
+	ExpectError(t, io.ErrShortBuffer, eb.Error())
+	ExpectError(t, context.Canceled, eb.Error())
+}
+
+func TestBuilderNested(t *testing.T) {
+	eb := NewBuilder("action failed")
+	eb.Add(New("Action 1").Withf("Inner: 1").Withf("Inner: 2"))
+	eb.Add(New("Action 2").Withf("Inner: 3"))
+
+	got := eb.String()
+	expected := `action failed
+  • Action 1
+    • Inner: 1
+    • Inner: 2
+  • Action 2
+    • Inner: 3`
+	ExpectEqual(t, got, expected)
+}