public async Task ParkService_GetAllParks_ReturnsFullList()
{
var underTest = new ParkService(_parkRepositoryMock.Object);
underTest.Should().NotBeNull("because we expect an instance to be created.");
var result = await underTest.GetAllParks() as IList <Park>;
result.Should().NotBeNull("because we expect a result.");
result.Should().HaveCount(DummyParks.Count(), "because the returned count should match DummyParks count.");
}