[feature] Basic config validation (#562)

* add optional config validation

* clarify that host and protocol are required

* add validation for host and protocol

* pass prerunArgs as a struct (validate by default)

internal/config/validate_test.go

@@ -0,0 +1,90 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package config_test
+
+import (
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+)
+
+type ConfigValidateTestSuite struct {
+	suite.Suite
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigOK() {
+	testrig.InitTestConfig()
+
+	err := config.Validate()
+	suite.NoError(err)
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigNoHost() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.Host, "")
+
+	err := config.Validate()
+	suite.EqualError(err, "host must be set")
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigNoProtocol() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.Protocol, "")
+
+	err := config.Validate()
+	suite.EqualError(err, "protocol must be set")
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigNoProtocolOrHost() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.Host, "")
+	viper.Set(config.Keys.Protocol, "")
+
+	err := config.Validate()
+	suite.EqualError(err, "host must be set; protocol must be set")
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigBadProtocol() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.Protocol, "foo")
+
+	err := config.Validate()
+	suite.EqualError(err, "protocol must be set to either http or https, provided value was foo")
+}
+
+func (suite *ConfigValidateTestSuite) TestValidateConfigBadProtocolNoHost() {
+	testrig.InitTestConfig()
+
+	viper.Set(config.Keys.Host, "")
+	viper.Set(config.Keys.Protocol, "foo")
+
+	err := config.Validate()
+	suite.EqualError(err, "host must be set; protocol must be set to either http or https, provided value was foo")
+}
+
+func TestConfigValidateTestSuite(t *testing.T) {
+	suite.Run(t, &ConfigValidateTestSuite{})
+}