MM-11174: Fix /msg slash command. (#9059)

app/command_msg_test.go

@@ -19,13 +19,47 @@ func TestMsgProvider(t *testing.T) {
 	team := th.CreateTeam()
 	th.LinkUserToTeam(th.BasicUser, team)
 	cmd := &msgProvider{}
+
+	// Check without permission to create a DM channel.
 	resp := cmd.DoCommand(th.App, &model.CommandArgs{
 		T:       i18n.IdentityTfunc(),
 		SiteURL: "http://test.url",
 		TeamId:  team.Id,
 		UserId:  th.BasicUser.Id,
+		Session: model.Session{
+			Roles: "",
+		},
 	}, "@"+th.BasicUser2.Username+" hello")
+
 	channelName := model.GetDMNameFromIds(th.BasicUser.Id, th.BasicUser2.Id)
+	assert.Equal(t, "api.command_msg.permission.app_error", resp.Text)
+	assert.Equal(t, "", resp.GotoLocation)
+
+	// Check with permission to create a DM channel.
+	resp = cmd.DoCommand(th.App, &model.CommandArgs{
+		T:       i18n.IdentityTfunc(),
+		SiteURL: "http://test.url",
+		TeamId:  team.Id,
+		UserId:  th.BasicUser.Id,
+		Session: model.Session{
+			Roles: model.SYSTEM_USER_ROLE_ID,
+		},
+	}, "@"+th.BasicUser2.Username+" hello")
+
+	assert.Equal(t, "", resp.Text)
+	assert.Equal(t, "http://test.url/"+team.Name+"/channels/"+channelName, resp.GotoLocation)
+
+	// Check without permission to post to an existing DM channel.
+	resp = cmd.DoCommand(th.App, &model.CommandArgs{
+		T:       i18n.IdentityTfunc(),
+		SiteURL: "http://test.url",
+		TeamId:  team.Id,
+		UserId:  th.BasicUser.Id,
+		Session: model.Session{
+			Roles: "",
+		},
+	}, "@"+th.BasicUser2.Username+" hello")
+
 	assert.Equal(t, "", resp.Text)
 	assert.Equal(t, "http://test.url/"+team.Name+"/channels/"+channelName, resp.GotoLocation)
 }