How can I if the new activity was started

Scenario:

1. The user starts the app
2. The user go to the "CreateAccountActivity"
3. In order to use the application the user has to fill the email and pass
4. The user clicks "create" which switches to the next activity.

@Test public void createAccountAndLogIn() { onView(withId(R.id.login_create)).perform(click()); onView(withId(R.id.create_email)).perform(clearText(),typeText("michbocian@gmail.com")); onView(withId(R.id.create_pass)).perform(clearText(),typeText("pass")); onView(withId(R.id.create_pass_repeat)).perform(clearText(),typeText("pass")); onView(withId(R.id.create_create_button)).perform(click()); }

How to check, after the last line, if the new "MainActivity" was lunched?