BrowserChannel example

new BootstrapFlashMessageImportanceMapper(), Notification::IMPORTANCE_LOW, 'success'],
        ];
    }

    private function buildBrowserChannel(Session $session, FlashMessageImportanceMapperInterface $mapper): BrowserChannel
    {
        $request = $this->createMock(Request::class);
        $request->method('getSession')->willReturn($session);
        $requestStack = $this->createStub(RequestStack::class);
        $requestStack->method('getCurrentRequest')->willReturn($request);

        return new BrowserChannel($requestStack, $mapper);
    }
}