### Question:
Layer implements Iterable<Neuron>, Serializable { public void calculate() { for (Neuron neuron : neurons) { neuron.calculate(); } } Layer();  Layer(int neuronsCount);  Layer(int neuronsCount, NeuronProperties neuronProperties); final void setParentNetwork(NeuralNetwork parent); final NeuralNetwork getParentNetwork(); final List<Neuron> getNeurons(); final void addNeuron(Neuron neuron); final void addNeuron(int index, Neuron neuron); final void setNeuron(int index, Neuron neuron); final void removeNeuron(Neuron neuron); final void removeNeuronAt(int index); final void removeAllNeurons(); Neuron getNeuronAt(int index); int indexOf(Neuron neuron); int getNeuronsCount(); void calculate(); void reset(); void initializeWeights(double value); String getLabel(); void setLabel(String label); boolean isEmpty(); @Override Iterator<Neuron> iterator();  }### Answer:
@Test public void testCalculate() { InputLayer input = new InputLayer(2); testneuron1.addInputConnection(input.getNeuronAt(0), 5); input.getNeuronAt(0).setInput(1); instance.calculate(); Step transfer = new Step(); assertEquals(transfer.getOutput(5), testneuron1.getOutput(), 0.0); input.getNeuronAt(0).setInput(-1); instance.calculate(); assertEquals(transfer.getOutput(-5), testneuron1.getOutput(), 0.0); }