Find a FloatingActionButton in Flutter test

I'm running a few widget tests in my Flutter app and came across this problem.

So, the page beeing called in the test is made only by a ListView.builder who builds a list of cards and an 'add more cards' floating button after it (the button is inside the ListView.builder).

According to Flutter documentation there's really no secret, you just find it and tap it like any other button widget.

await tester.tap(find.byType(FloatingActionButton));

But I'm getting a "Bad state: No such element" when the test reaches that line

This is the full widget hierarchy for that page and here is the code for the test:

testWidgets('Connecting with new machine', (WidgetTester tester) async {
  await tester.pumpWidget(makeWigdetTestable(child: MaquinasPage()));
  await tester.tap(find.byType(FloatingActionButton));
  await tester.pumpAndSettle();

  expect(find.text('new machine connected'), findsOneWidget);

Note: The 'makeWidgetTestable' widget just returns a MaterialApp whose 'home' property is the parameter 'MaquinasPage()'.