TerminalView

Lookup

import { BottomBarPanel, TerminalView } from 'vscode-extension-tester';
...
const terminalView = await new BottomBarPanel().openTerminalView();

Terminal Selection

// get names of all available terminals
const names = await terminalView.getChannelNames();
// select a terminal from the drop box by name
await terminalView.selectChannel('Git');