Merge pull request #24 from go-faster/test/add-multi-comp-test

test: add simple compatibility test for new `errors.Join`

cmd/gowrapper/main.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Binary gowrapper replaces exisiting xerrors calls with errors analog.
 package main
 
 import (

multi_test.go

@@ -0,0 +1,42 @@
+//go:build go1.20
+
+package errors_test
+
+import (
+	stderrors "errors"
+	"io"
+	"testing"
+
+	"github.com/go-faster/errors"
+)
+
+var ErrValue = errors.New("value error")
+
+type Error struct{}
+
+func (*Error) Error() string {
+	return "typed error"
+}
+
+// Compatibility test for multi-errors generated by [errors.Join]
+func TestMulti(t *testing.T) {
+	typedErr := new(Error)
+	wrappedErr := errors.Wrap(io.ErrClosedPipe, "wrapped error")
+
+	errs := stderrors.Join(ErrValue, typedErr, wrappedErr)
+
+	// Test Is.
+	if !errors.Is(errs, ErrValue) {
+		t.Errorf("Expected Is(%+v, %+v) == true", errs, ErrValue)
+	}
+
+	// Test As.
+	if target := new(*Error); !errors.As(errs, target) {
+		t.Errorf("Expected As(%+v, %T) == true", errs, target)
+	}
+
+	// Test wrapping.
+	if !errors.Is(errs, io.ErrClosedPipe) {
+		t.Errorf("Expected Is(%+v, %+v) == true", errs, ErrValue)
+	}
+}