Switch to Postgres when running tests and turn off the fsync setting (#13678)

* Run all tests fasts in postgres

* Moving postgres config to a file

* Addressing PR review comments

* Testing against mysql in the CI to keep things less changed

* Revert "Testing against mysql in the CI to keep things less changed"

This reverts commit fc940c111db269a821c54e005d76df87cb70e031.

* Fixing a test broken in postgres but working in mysql

* Fixing some tests

* Fixing some config tests with postgres

* Fixing the rest of config tests

* Fixing govet error

* Fixing search tests for postgres

cmd/mattermost/commands/config_test.go

@@ -5,7 +5,6 @@ package commands
 
 import (
 	"encoding/json"
-	"fmt"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -81,6 +80,13 @@ type TestPluginSettings struct {
 	SignaturePublicKeyFiles []string
 }
 
+func getDsn(driver string, source string) string {
+	if driver == model.DATABASE_DRIVER_MYSQL {
+		return driver + "://" + source
+	}
+	return source
+}
+
 func TestConfigValidate(t *testing.T) {
 	th := Setup()
 	defer th.TearDown()
@@ -533,7 +539,7 @@ func TestConfigMigrate(t *testing.T) {
 	defer th.TearDown()
 
 	sqlSettings := mainHelper.GetSQLSettings()
-	sqlDSN := fmt.Sprintf("%s://%s", *sqlSettings.DriverName, *sqlSettings.DataSource)
+	sqlDSN := getDsn(*sqlSettings.DriverName, *sqlSettings.DataSource)
 	fileDSN := "config.json"
 
 	ds, err := config.NewStore(sqlDSN, false)