Remove global cfg vars (#8099)

* remove global cfg vars

* enterprise update

app/config_test.go

@@ -0,0 +1,56 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package app
+
+import (
+	"testing"
+
+	"github.com/mattermost/mattermost-server/model"
+)
+
+func TestConfigListener(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+
+	originalSiteName := th.App.Config().TeamSettings.SiteName
+	th.App.UpdateConfig(func(cfg *model.Config) {
+		cfg.TeamSettings.SiteName = "test123"
+	})
+
+	listenerCalled := false
+	listener := func(oldConfig *model.Config, newConfig *model.Config) {
+		if listenerCalled {
+			t.Fatal("listener called twice")
+		}
+
+		if oldConfig.TeamSettings.SiteName != "test123" {
+			t.Fatal("old config contains incorrect site name")
+		} else if newConfig.TeamSettings.SiteName != originalSiteName {
+			t.Fatal("new config contains incorrect site name")
+		}
+
+		listenerCalled = true
+	}
+	listenerId := th.App.AddConfigListener(listener)
+	defer th.App.RemoveConfigListener(listenerId)
+
+	listener2Called := false
+	listener2 := func(oldConfig *model.Config, newConfig *model.Config) {
+		if listener2Called {
+			t.Fatal("listener2 called twice")
+		}
+
+		listener2Called = true
+	}
+	listener2Id := th.App.AddConfigListener(listener2)
+	defer th.App.RemoveConfigListener(listener2Id)
+
+	th.App.ReloadConfig()
+
+	if !listenerCalled {
+		t.Fatal("listener should've been called")
+	} else if !listener2Called {
+		t.Fatal("listener 2 should've been called")
+	}
+}