add unit tests

pkg/errs/error_test.go

@@ -0,0 +1,26 @@
+package errs
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMultiError(t *testing.T) {
+	err1 := errors.New("error1 message")
+	err2 := errors.New("error2 message")
+	err := NewMultiErrorOrNil(err1, err2)
+	assert.Equal(t, "multi errors: error1 message, error2 message", err.Error())
+}
+
+func TestNewMultiErrorOrNilWithOnlyOneParamerter(t *testing.T) {
+	err1 := errors.New("error1 message")
+	err := NewMultiErrorOrNil(err1)
+	assert.Equal(t, err1, err)
+}
+
+func TestNewMultiErrorOrNilWithoutOneParamerter(t *testing.T) {
+	err := NewMultiErrorOrNil()
+	assert.Nil(t, err)
+}