feat: add custom error type (#1)

go.mod

@@ -1,3 +1,11 @@
 module gitea.dwysokinski.me/Kichiyaki/notificationarr
 
 go 1.18
+
+require github.com/stretchr/testify v1.8.0
+
+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
+)

go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+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/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+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 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/domain/errors.go

@@ -0,0 +1,82 @@
+package domain
+
+import "fmt"
+
+type ErrorCode uint8
+
+const (
+	ErrorCodeUnknown ErrorCode = iota
+)
+
+func (e ErrorCode) String() string {
+	switch e {
+	case ErrorCodeUnknown:
+		fallthrough
+	default:
+		return "internal-server-error"
+	}
+}
+
+type Error struct {
+	code ErrorCode
+	msg  string
+	err  error
+}
+
+type ErrorOption func(err Error) Error
+
+func WithCode(code ErrorCode) ErrorOption {
+	return func(err Error) Error {
+		err.code = code
+		return err
+	}
+}
+
+func WithErr(wrap error) ErrorOption {
+	return func(err Error) Error {
+		err.err = wrap
+		return err
+	}
+}
+
+func WithMessage(msg string) ErrorOption {
+	return func(err Error) Error {
+		err.msg = msg
+		return err
+	}
+}
+
+func WithMessagef(format string, a ...any) ErrorOption {
+	return func(err Error) Error {
+		err.msg = fmt.Sprintf(format, a...)
+		return err
+	}
+}
+
+func NewError(opts ...ErrorOption) Error {
+	var err Error
+	for _, opt := range opts {
+		err = opt(err)
+	}
+	return err
+}
+
+func (err Error) Error() string {
+	if err.err != nil {
+		return err.msg + ": " + err.err.Error()
+	}
+
+	return err.msg
+}
+
+func (err Error) Message() string {
+	return err.msg
+}
+
+func (err Error) Code() ErrorCode {
+	return err.code
+}
+
+func (err Error) Unwrap() error {
+	return err.err
+}

internal/domain/errors_test.go

@@ -0,0 +1,67 @@
+package domain_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"gitea.dwysokinski.me/Kichiyaki/notificationarr/internal/domain"
+)
+
+func TestErrorCode_String(t *testing.T) {
+	t.Parallel()
+
+	assert.Equal(t, domain.ErrorCodeUnknown.String(), "internal-server-error")
+}
+
+func TestError(t *testing.T) {
+	errToWrap := errors.New("WithErr")
+	tests := []struct {
+		name         string
+		options      []domain.ErrorOption
+		expectedCode domain.ErrorCode
+		expectedErr  error
+		expectedMsg  string
+	}{
+		{
+			name: "OK: WithCode, WithMessage",
+			options: []domain.ErrorOption{
+				domain.WithCode(domain.ErrorCodeUnknown),
+				domain.WithMessage("err err"),
+			},
+			expectedCode: domain.ErrorCodeUnknown,
+			expectedErr:  nil,
+			expectedMsg:  "err err",
+		},
+		{
+			name: "OK: WithCode, WithMessagef, WithErr",
+			options: []domain.ErrorOption{
+				domain.WithCode(domain.ErrorCodeUnknown),
+				domain.WithMessagef("xxx %d", 25),
+				domain.WithErr(errToWrap),
+			},
+			expectedCode: domain.ErrorCodeUnknown,
+			expectedErr:  errToWrap,
+			expectedMsg:  "xxx 25",
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			err := domain.NewError(tt.options...)
+			assert.Equal(t, tt.expectedCode, err.Code())
+			assert.Equal(t, tt.expectedMsg, err.Message())
+			assert.ErrorIs(t, tt.expectedErr, err.Unwrap())
+			if tt.expectedErr != nil {
+				assert.Equal(t, tt.expectedMsg+": "+tt.expectedErr.Error(), err.Error())
+			} else {
+				assert.Equal(t, tt.expectedMsg, err.Error())
+			}
+		})
+	}
+}

internal/service/notification.go

@@ -1,4 +0,0 @@
-package service
-
-type Notification struct {
-}