public void PerceptronThrowsErrorWhenWeightsAreAllZero()
{
_network.GetAllConnections().Enumerate(connection => connection.Properties.Weight = 0d);
//Note: NullReferenceException means exception wasn't thrown
var exception = Assert.Throws <InvalidOperationException>(() => _perceptron.CheckTopology());
exception.Message.Should().Be(Perceptron.WeightsAreAllZero);
}