Android - How to click on an item on a navigation drawer using Espresso?

@Test
public void clickOnYourNavigationItem_ShowsYourScreen() {
    // Open Drawer to click on navigation.
    onView(withId(R.id.drawer_layout))
        .check(matches(isClosed(Gravity.LEFT))) // Left Drawer should be closed.
        .perform(DrawerActions.open()); // Open Drawer

    // Start the screen of your activity.
    onView(withId(R.id.nav_view))
        .perform(NavigationViewActions.navigateTo(R.id.your_navigation_menu_item));

    // Check that you Activity was opened.
    String expectedNoStatisticsText = InstrumentationRegistry.getTargetContext()
        .getString(R.string.no_item_available);
    onView(withId(R.id.no_statistics)).check(matches(withText(expectedNoStatisticsText)));
}

This does exactly what you are looking for.

Other examples are available here or here

Incase someone else lands to this question and he/she is using kotlin you can add extension function on ActivityScenario class to grab drawer icon or back button

For more description check this GOOGLE-TESTING-CODELAB-8

fun <T: Activity> ActivityScenario<T>.getToolbarNavigationContentDescriptor(): String {
    var description = ""
    onActivity {
        description = it.findViewById<Toolbar>(R.id.toolbar).navigationContentDescription as String
    }
    return description
}

On your tests, you can do something like this

// Check drawer is closed
onView(withId(R.id.drawer_layout)).check(matches(isClosed(Gravity.START)))

// Click drawer icon
onView(
    withContentDescription(
        scenario.getToolbarNavigationContentDescriptor()
    )
).perform(click())

// Check if drawer is open
onView(withId(R.id.drawer_layout)).check(matches(isOpen(Gravity.START)))

Happy coding . . .