public async Task GetMonstersAsync_WhenRepositoryIsEmpty_ShouldReturnEmptyListOfMonsters() { // Setup _mockMonsterRepository .Setup(repository => repository.GetMonsters()) .ReturnsAsync(Enumerable.Empty <Monster>()); var expected = Enumerable.Empty <string>(); // Execute var actual = await fixture.GetMonstersAsync(); // Verify _mockMonsterRepository.VerifyAll(); actual.Should().BeEquivalentTo(expected); }