Test runs of buses will begin April 23 on the extension of the Orange Line busway between the Canoga Avenue stop and the Chatsworth Metrolink station. The testing will involve the traffic signal coordination, and the public address systems, security cameras, and announcement signage at the stations, said Hitesh Patel, the project manager for the extension. “Once we get toward the opening there will be a full test at operating levels,” Patel said. The extension is scheduled to open in June. The project was budgeted at $215 million but has cost $180 million so far, according to Metro spokesman Dave Sotero. Drivers need to be vigilant while the testing is taking place because of unfamiliarity of buses crossing streets, Sotero said. “They need to be cautious not to run red signal to avoid hitting buses as they are going through,” Sotero added.