fix for #281 (#282)

Co-authored-by: Jan Zombik <[email protected]>

gqlerror/error.go

@@ -99,7 +99,7 @@ func (errs List) Is(target error) bool {
 
 func (errs List) As(target interface{}) bool {
 	for _, err := range errs {
-		if errors.As(err, &target) {
+		if errors.As(err, target) {
 			return true
 		}
 	}

gqlerror/error_test.go

@@ -1,12 +1,35 @@
 package gqlerror
 
 import (
+	"reflect"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 	"github.com/vektah/gqlparser/v2/ast"
 )
 
+type testError struct {
+	message string
+}
+
+func (e testError) Error() string {
+	return e.message
+}
+
+var (
+	underlyingError = testError{
+		"Underlying error",
+	}
+
+	error1 = &Error{
+		Message: "Some error 1",
+	}
+	error2 = &Error{
+		Err:     underlyingError,
+		Message: "Some error 2",
+	}
+)
+
 func TestErrorFormatting(t *testing.T) {
 	t.Run("without filename", func(t *testing.T) {
 		err := ErrorLocf("", 66, 2, "kabloom")
@@ -28,3 +51,118 @@ func TestErrorFormatting(t *testing.T) {
 		require.Equal(t, `input: a[1].b kabloom`, err.Error())
 	})
 }
+
+func TestList_As(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name        string
+		errs        List
+		target      any
+		wantsTarget any
+		targetFound bool
+	}{
+		{
+			name:   "Empty list",
+			errs:   List{},
+		},
+		{
+			name:        "List with one error",
+			errs:        List{error1},
+			target:      new(*Error),
+			wantsTarget: &error1,
+			targetFound: true,
+		},
+		{
+			name:        "List with multiple errors 1",
+			errs:        List{error1, error2},
+			target:      new(*Error),
+			wantsTarget: &error1,
+			targetFound: true,
+		},
+		{
+			name:        "List with multiple errors 2",
+			errs:        List{error1, error2},
+			target:      new(testError),
+			wantsTarget: &underlyingError,
+			targetFound: true,
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			targetFound := tt.errs.As(tt.target)
+
+			if targetFound != tt.targetFound {
+				t.Errorf("List.As() = %v, want %v", targetFound, tt.targetFound)
+			}
+
+			if tt.targetFound && !reflect.DeepEqual(tt.target, tt.wantsTarget) {
+				t.Errorf("target = %v, want %v", tt.target, tt.wantsTarget)
+			}
+		})
+	}
+}
+
+func TestList_Is(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name             string
+		errs             List
+		target           error
+		hasMatchingError bool
+	}{
+		{
+			name:             "Empty list",
+			errs:             List{},
+			target:           new(Error),
+			hasMatchingError: false,
+		},
+		{
+			name: "List with one error",
+			errs: List{
+				error1,
+			},
+			target:           error1,
+			hasMatchingError: true,
+		},
+		{
+			name: "List with multiple errors 1",
+			errs: List{
+				error1,
+				error2,
+			},
+			target:           error2,
+			hasMatchingError: true,
+		},
+		{
+			name: "List with multiple errors 2",
+			errs: List{
+				error1,
+				error2,
+			},
+			target:           underlyingError,
+			hasMatchingError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			hasMatchingError := tt.errs.Is(tt.target)
+			if hasMatchingError != tt.hasMatchingError {
+				t.Errorf("List.Is() = %v, want %v", hasMatchingError, tt.hasMatchingError)
+			}
+			if hasMatchingError && tt.target == nil {
+				t.Errorf("List.Is() returned nil target, wants concrete error")
+			}
+		})
+	}
+}