add psalm and travis check

Structural/Facade/Tests/FacadeTest.php

@@ -2,6 +2,7 @@
 
 namespace DesignPatterns\Structural\Facade\Tests;
 
+use DesignPatterns\Structural\Facade\Bios;
 use DesignPatterns\Structural\Facade\Facade;
 use DesignPatterns\Structural\Facade\OperatingSystem;
 use PHPUnit\Framework\TestCase;
@@ -10,27 +11,20 @@ class FacadeTest extends TestCase
 {
     public function testComputerOn()
     {
-        /** @var OperatingSystem|\PHPUnit_Framework_MockObject_MockObject $os */
-        $os = $this->createMock('DesignPatterns\Structural\Facade\OperatingSystem');
+        $os = $this->createMock(OperatingSystem::class);
 
         $os->method('getName')
             ->will($this->returnValue('Linux'));
 
-        $bios = $this->getMockBuilder('DesignPatterns\Structural\Facade\Bios')
-            ->setMethods(['launch', 'execute', 'waitForKeyPress'])
-            ->disableAutoload()
-            ->getMock();
+        $bios = $this->createMock(Bios::class);
 
-        $bios->expects($this->once())
-            ->method('launch')
+        $bios->method('launch')
             ->with($os);
 
+        /** @noinspection PhpParamsInspection */
         $facade = new Facade($bios, $os);
-
-        // the facade interface is simple
         $facade->turnOn();
 
-        // but you can also access the underlying components
         $this->assertSame('Linux', $os->getName());
     }
 }

Structural/Proxy/HeavyBankAccount.php

@@ -20,6 +20,6 @@ class HeavyBankAccount implements BankAccount
         // years and decades ago must be fetched from a database or web service
         // and the balance must be calculated from it
 
-        return array_sum($this->transactions);
+        return (int) array_sum($this->transactions);
     }
 }

Structural/Registry/Tests/RegistryTest.php

@@ -9,9 +9,6 @@ use PHPUnit\Framework\TestCase;
 
 class RegistryTest extends TestCase
 {
-    /**
-     * @var Service|MockObject
-     */
     private $service;
 
     protected function setUp(): void
@@ -21,6 +18,7 @@ class RegistryTest extends TestCase
 
     public function testSetAndGetLogger()
     {
+        /** @noinspection PhpParamsInspection */
         Registry::set(Registry::LOGGER, $this->service);
 
         $this->assertSame($this->service, Registry::get(Registry::LOGGER));