MM-10910 fix join and open channel commands to work with tilde (#8984)

* MM-10910 fix join and open channel commands to work with tilde

* Fix lint

* Add basic tests for command_join

app/command_join_test.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2018-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package app
+
+import (
+	"testing"
+	"github.com/mattermost/mattermost-server/model"
+	"github.com/nicksnyder/go-i18n/i18n"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestJoinCommandNoChannel(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+
+	if testing.Short() {
+		t.SkipNow()
+	}
+
+	cmd := &JoinProvider{}
+	resp := cmd.DoCommand(th.App, &model.CommandArgs{
+		T:      i18n.IdentityTfunc(),
+		UserId: th.BasicUser2.Id,
+		SiteURL: "http://test.url",
+		TeamId:      th.BasicTeam.Id,
+	}, "asdsad")
+
+	assert.Equal(t, "api.command_join.list.app_error", resp.Text)
+}
+
+func TestJoinCommandForExistingChannel(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+
+	if testing.Short() {
+		t.SkipNow()
+	}
+
+	channel2, _ := th.App.CreateChannel(&model.Channel{
+	  DisplayName: "AA",
+	  Name:        "aa" + model.NewId() + "a",
+	  Type:        model.CHANNEL_OPEN,
+	  TeamId:      th.BasicTeam.Id,
+	  CreatorId:   th.BasicUser.Id,
+	}, false)
+
+
+	cmd := &JoinProvider{}
+	resp := cmd.DoCommand(th.App, &model.CommandArgs{
+		T:      i18n.IdentityTfunc(),
+		UserId: th.BasicUser2.Id,
+		SiteURL: "http://test.url",
+		TeamId:      th.BasicTeam.Id,
+	}, channel2.Name)
+
+	assert.Equal(t, "", resp.Text)
+	assert.Equal(t, "http://test.url/"+th.BasicTeam.Name+"/channels/"+channel2.Name, resp.GotoLocation)
+}
+
+func TestJoinCommandWithTilde(t *testing.T) {
+	th := Setup().InitBasic()
+	defer th.TearDown()
+
+	if testing.Short() {
+		t.SkipNow()
+	}
+
+	channel2, _ := th.App.CreateChannel(&model.Channel{
+	  DisplayName: "AA",
+	  Name:        "aa" + model.NewId() + "a",
+	  Type:        model.CHANNEL_OPEN,
+	  TeamId:      th.BasicTeam.Id,
+	  CreatorId:   th.BasicUser.Id,
+	}, false)
+
+
+	cmd := &JoinProvider{}
+	resp := cmd.DoCommand(th.App, &model.CommandArgs{
+		T:      i18n.IdentityTfunc(),
+		UserId: th.BasicUser2.Id,
+		SiteURL: "http://test.url",
+		TeamId:      th.BasicTeam.Id,
+	}, "~"+channel2.Name)
+
+	assert.Equal(t, "", resp.Text)
+	assert.Equal(t, "http://test.url/"+th.BasicTeam.Name+"/channels/"+channel2.Name, resp.GotoLocation)
+}