HEAVY: finish music service migration, tidy up services, more tests

errors/notexist.go

@@ -0,0 +1,16 @@
+package errors
+
+type NotExistError struct {
+    query string
+}
+func NewNotExistError(query string) *NotExistError {
+    return &NotExistError{ query: query }
+}
+func (err *NotExistError) Error() string {
+    return err.query
+}
+func IsNotExistError(err error) bool {
+    _, ok := err.(*NotExistError)
+    return ok
+}
+

errors/notexist_test.go

@@ -0,0 +1,26 @@
+package errors_test
+
+import (
+	"arimelody-web/errors"
+	goErrors "errors"
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func Test_NotExistError(t *testing.T) {
+    var err error
+    message := "entity does not exist"
+
+    t.Run("can create error", func(t *testing.T) {
+        err = errors.NewNotExistError(message)
+        assert.Error(t, err, message)
+    })
+
+    t.Run("validator returns true for valid error", func(t *testing.T) {
+        assert.Equal(t, errors.IsNotExistError(err), true)
+    })
+    t.Run("validator returns false for invalid error", func(t *testing.T) {
+        assert.Equal(t, errors.IsNotExistError(goErrors.New("other error")), false)
+    })
+}

errors/validation.go

@@ -0,0 +1,15 @@
+package errors
+
+type ValidationError struct {
+    message string
+}
+func NewValidationError(message string) *ValidationError {
+    return &ValidationError{ message: message }
+}
+func (err *ValidationError) Error() string {
+    return err.message
+}
+func IsValidationError(err error) bool {
+    _, ok := err.(*ValidationError)
+    return ok
+}

errors/validation_test.go

@@ -0,0 +1,26 @@
+package errors_test
+
+import (
+	"arimelody-web/errors"
+	goErrors "errors"
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func Test_ValidationError(t *testing.T) {
+    var err error
+    message := "invalid input"
+
+    t.Run("can create error", func(t *testing.T) {
+        err = errors.NewValidationError(message)
+        assert.Error(t, err, message)
+    })
+
+    t.Run("validator returns true for valid error", func(t *testing.T) {
+        assert.Equal(t, errors.IsValidationError(err), true)
+    })
+    t.Run("validator returns false for invalid error", func(t *testing.T) {
+        assert.Equal(t, errors.IsValidationError(goErrors.New("other error")), false)
+    })
+}