diff --git a/ecs.yml b/ecs.yml
index b19571e..21b30e9 100644
--- a/ecs.yml
+++ b/ecs.yml
@@ -18,7 +18,8 @@ services:
     PhpCsFixer\Fixer\Operator\BinaryOperatorSpacesFixer:
         align_double_arrow: false
         align_equals: false
-
+    PhpCsFixer\Fixer\PhpUnit\PhpUnitTestCaseStaticMethodCallsFixer:
+        call_type: 'self'
     # phpdoc
     PhpCsFixer\Fixer\Phpdoc\PhpdocSeparationFixer: ~
     PhpCsFixer\Fixer\Phpdoc\PhpdocAlignFixer: ~
diff --git a/src/Helper/Optimizer/Optimizer.php b/src/Helper/Optimizer/Optimizer.php
index 99a82ab..54331e9 100644
--- a/src/Helper/Optimizer/Optimizer.php
+++ b/src/Helper/Optimizer/Optimizer.php
@@ -48,6 +48,11 @@ abstract class Optimizer
         return $this;
     }
 
+    public function theta(): array
+    {
+        return $this->theta;
+    }
+
     /**
      * Executes the optimization with the given samples & targets
      * and returns the weights
diff --git a/src/NeuralNetwork/Network/MultilayerPerceptron.php b/src/NeuralNetwork/Network/MultilayerPerceptron.php
index e9e6b51..beefb1e 100644
--- a/src/NeuralNetwork/Network/MultilayerPerceptron.php
+++ b/src/NeuralNetwork/Network/MultilayerPerceptron.php
@@ -129,6 +129,16 @@ abstract class MultilayerPerceptron extends LayeredNetwork implements Estimator,
         return $result;
     }
 
+    public function getLearningRate(): float
+    {
+        return $this->learningRate;
+    }
+
+    public function getBackpropagation(): Backpropagation
+    {
+        return $this->backpropagation;
+    }
+
     /**
      * @param mixed $target
      */
diff --git a/src/NeuralNetwork/Training/Backpropagation.php b/src/NeuralNetwork/Training/Backpropagation.php
index 6c9af98..69a3e2a 100644
--- a/src/NeuralNetwork/Training/Backpropagation.php
+++ b/src/NeuralNetwork/Training/Backpropagation.php
@@ -34,6 +34,11 @@ class Backpropagation
         $this->learningRate = $learningRate;
     }
 
+    public function getLearningRate(): float
+    {
+        return $this->learningRate;
+    }
+
     /**
      * @param mixed $targetClass
      */
diff --git a/tests/Helper/Optimizer/OptimizerTest.php b/tests/Helper/Optimizer/OptimizerTest.php
index 97af2d2..184f6c7 100644
--- a/tests/Helper/Optimizer/OptimizerTest.php
+++ b/tests/Helper/Optimizer/OptimizerTest.php
@@ -26,9 +26,7 @@ class OptimizerTest extends TestCase
         $optimizer = $this->getMockForAbstractClass(Optimizer::class, [2]);
         $object = $optimizer->setTheta([0.3, 1]);
 
-        $theta = self::getObjectAttribute($optimizer, 'theta');
-
         self::assertSame($object, $optimizer);
-        self::assertSame([0.3, 1], $theta);
+        self::assertSame([0.3, 1], $object->theta());
     }
 }
diff --git a/tests/NeuralNetwork/Network/MultilayerPerceptronTest.php b/tests/NeuralNetwork/Network/MultilayerPerceptronTest.php
index 1495136..6123f9b 100644
--- a/tests/NeuralNetwork/Network/MultilayerPerceptronTest.php
+++ b/tests/NeuralNetwork/Network/MultilayerPerceptronTest.php
@@ -55,14 +55,12 @@ class MultilayerPerceptronTest extends TestCase
             [5, [3], [0, 1], 1000, null, 0.42]
         );
 
-        self::assertEquals(0.42, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.42, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.42, $mlp->getLearningRate());
+        self::assertEquals(0.42, $mlp->getBackpropagation()->getLearningRate());
 
         $mlp->setLearningRate(0.24);
-        self::assertEquals(0.24, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.24, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.24, $mlp->getLearningRate());
+        self::assertEquals(0.24, $mlp->getBackpropagation()->getLearningRate());
     }
 
     public function testLearningRateSetterWithCustomActivationFunctions(): void
@@ -75,14 +73,12 @@ class MultilayerPerceptronTest extends TestCase
             [5, [[3, $activation_function], [5, $activation_function]], [0, 1], 1000, null, 0.42]
         );
 
-        self::assertEquals(0.42, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.42, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.42, $mlp->getLearningRate());
+        self::assertEquals(0.42, $mlp->getBackpropagation()->getLearningRate());
 
         $mlp->setLearningRate(0.24);
-        self::assertEquals(0.24, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.24, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.24, $mlp->getLearningRate());
+        self::assertEquals(0.24, $mlp->getBackpropagation()->getLearningRate());
     }
 
     public function testLearningRateSetterWithLayerObject(): void
@@ -95,14 +91,12 @@ class MultilayerPerceptronTest extends TestCase
             [5, [new Layer(3, Neuron::class, $activation_function), new Layer(5, Neuron::class, $activation_function)], [0, 1], 1000, null, 0.42]
         );
 
-        self::assertEquals(0.42, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.42, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.42, $mlp->getLearningRate());
+        self::assertEquals(0.42, $mlp->getBackpropagation()->getLearningRate());
 
         $mlp->setLearningRate(0.24);
-        self::assertEquals(0.24, self::readAttribute($mlp, 'learningRate'));
-        $backprop = self::readAttribute($mlp, 'backpropagation');
-        self::assertEquals(0.24, self::readAttribute($backprop, 'learningRate'));
+        self::assertEquals(0.24, $mlp->getLearningRate());
+        self::assertEquals(0.24, $mlp->getBackpropagation()->getLearningRate());
     }
 
     /**