public async Task Verify_CreateFlightsAsync_Invoked()
{
// Arrange
var fileManagerMock = new Mock <IFileManager <Flight> >();
fileManagerMock.Setup(x => x.WriteToJsonAsync(It.IsAny <string>(), It.IsAny <List <Flight> >())).Verifiable();
var sut = new FlightRepository(fileManagerMock.Object);
// Act
await sut.CreateFlightsAsync(new List <Flight>());
// Assert
Mock.Verify();
}