Add testing helper func (#112)

temperror/go.mod

@@ -1,3 +1,11 @@
 module github.com/hashicorp/go-secure-stdlib/temperror
 
 go 1.19
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

temperror/go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

temperror/temperror.go

@@ -24,3 +24,16 @@ func New(inner error) tempError {
 func (t tempError) Temporary() bool {
 	return true
 }
+
+// IsTempError returns whether it is a temporary error to avoid having to use it
+// as it is in the gRPC source code, e.g.:
+//
+//	if ne, ok := err.(interface{ Temporary() bool }); !ok || !ne.Temporary() {
+//
+// This function does that for you :-)
+func IsTempError(err error) bool {
+	if ne, ok := err.(interface{ Temporary() bool }); !ok || !ne.Temporary() {
+		return false
+	}
+	return true
+}

temperror/temperror_test.go

@@ -0,0 +1,34 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package temperror
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTempError(t *testing.T) {
+	tests := []struct {
+		name       string
+		expectTemp bool
+		input      error
+	}{
+		{
+			name:       "temp-error",
+			input:      New(errors.New("this is a temporary error")),
+			expectTemp: true,
+		},
+		{
+			name:  "not-temp-error",
+			input: errors.New("this is not a temporary error"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.expectTemp, IsTempError(tt.input))
+		})
+	}
+}