implements and test multilayer perceptron methods

tests/Phpml/NeuralNetwork/Network/MultilayerPerceptronTest.php

@@ -0,0 +1,73 @@
+<?php
+
+declare (strict_types = 1);
+
+namespace tests\Phpml\NeuralNetwork\Network;
+
+use Phpml\NeuralNetwork\Network\MultilayerPerceptron;
+use Phpml\NeuralNetwork\Node\Neuron;
+
+class MultilayerPerceptronTest extends \PHPUnit_Framework_TestCase
+{
+    public function testMultilayerPerceptronLayersInitialization()
+    {
+        $mlp = new MultilayerPerceptron([2, 2, 1]);
+
+        $this->assertCount(3, $mlp->getLayers());
+
+        $layers = $mlp->getLayers();
+
+        // input layer
+        $this->assertCount(3, $layers[0]->getNodes());
+        $this->assertNotContainsOnly(Neuron::class, $layers[0]->getNodes());
+
+        // hidden layer
+        $this->assertCount(3, $layers[1]->getNodes());
+        $this->assertNotContainsOnly(Neuron::class, $layers[0]->getNodes());
+
+        // output layer
+        $this->assertCount(1, $layers[2]->getNodes());
+        $this->assertContainsOnly(Neuron::class, $layers[2]->getNodes());
+    }
+
+    public function testSynapsesGeneration()
+    {
+        $mlp = new MultilayerPerceptron([2, 2, 1]);
+        $layers = $mlp->getLayers();
+
+        foreach ($layers[1]->getNodes() as $node) {
+            if ($node instanceof Neuron) {
+                $synapses = $node->getSynapses();
+                $this->assertCount(3, $synapses);
+
+                $synapsesNodes = $this->getSynapsesNodes($synapses);
+                foreach ($layers[0]->getNodes() as $prevNode) {
+                    $this->assertContains($prevNode, $synapsesNodes);
+                }
+            }
+        }
+    }
+
+    /**
+     * @param array $synapses
+     *
+     * @return array
+     */
+    private function getSynapsesNodes(array $synapses): array
+    {
+        $nodes = [];
+        foreach ($synapses as $synapse) {
+            $nodes[] = $synapse->getNode();
+        }
+
+        return $nodes;
+    }
+
+    /**
+     * @expectedException \Phpml\Exception\InvalidArgumentException
+     */
+    public function testThrowExceptionOnInvalidLayersNumber()
+    {
+        new MultilayerPerceptron([2]);
+    }
+}