[browser tests] Delay exit after test finish

When running the suite in headless mode, it exits as soon as the mocha tests
are done executing. In some cases where there are lots of errors to report[1],
the final report did not have the chance to be printed-out, and so we were
left wondering about the details of what caused the failures.

[1]: basically the final pass/not passes/skip count as well as details about
the failed tests.

Signed-off-by: Marc Dumais <marc.dumais@ericsson.com>

dev-packages/cli/src/run-test.ts

@@ -67,6 +67,8 @@ export default async function runTest(options: TestOptions): Promise<void> {
                 require('puppeteer-to-istanbul').write([...jsCoverage, ...cssCoverage]);
             }
             if (exit) {
+                // allow a bit of time to finish printing-out test results
+                await new Promise(resolve => setTimeout(resolve, 1000));
                 await testPage.close();
                 process.exit(failures > 0 ? 1 : 0);
             }