[FEATURE] InvalidMutexException added

Classes/Configuration/Exception/InvalidMutexException.php

+<?php
+
+namespace Higidi\Lock\Configuration\Exception;
+
+/**
+ * Exception is thrown if invalid mutex is trying to set.
+ */
+class InvalidMutexException extends InvalidConfigurationException
+{
+}

Tests/Unit/Configuration/Exception/InvalidMutexExceptionTest.php

+<?php
+
+namespace Higidi\Lock\Tests\Unit\Configuration\Exception;
+
+use Higidi\Lock\Configuration\Exception\InvalidConfigurationException;
+use Higidi\Lock\Configuration\Exception\InvalidMutexException;
+use Nimut\TestingFramework\TestCase\UnitTestCase;
+
+/**
+ * Test case for "\Higidi\Lock\Configuration\Exception\InvalidMutexException".
+ *
+ * @covers \Higidi\Lock\Configuration\Exception\InvalidMutexException
+ */
+class InvalidMutexExceptionTest extends UnitTestCase
+{
+    /**
+     * @test
+     */
+    public function itExtendsTheInvalidConfigurationException()
+    {
+        $sut = new InvalidMutexException();
+
+        $this->assertInstanceOf(InvalidConfigurationException::class, $sut);
+    }
+}