add psalm and travis check

.travis.yml

@@ -24,3 +24,4 @@ install:
 script:
   - vendor/bin/phpunit
   - vendor/bin/phpcs .
+  - vendor/bin/psalm --show-info=false

Behavioral/ChainOfResponsibilities/Tests/ChainTest.php

@@ -5,7 +5,10 @@ namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Tests;
 use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
 use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\HttpInMemoryCacheHandler;
 use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\SlowDatabaseHandler;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\UriInterface;
 
 class ChainTest extends TestCase
 {
@@ -24,11 +27,11 @@ class ChainTest extends TestCase
 
     public function testCanRequestKeyInFastStorage()
     {
-        $uri = $this->createMock('Psr\Http\Message\UriInterface');
+        $uri = $this->createMock(UriInterface::class);
         $uri->method('getPath')->willReturn('/foo/bar');
         $uri->method('getQuery')->willReturn('index=1');
 
-        $request = $this->createMock('Psr\Http\Message\RequestInterface');
+        $request = $this->createMock(RequestInterface::class);
         $request->method('getMethod')
             ->willReturn('GET');
         $request->method('getUri')->willReturn($uri);
@@ -38,11 +41,11 @@ class ChainTest extends TestCase
 
     public function testCanRequestKeyInSlowStorage()
     {
-        $uri = $this->createMock('Psr\Http\Message\UriInterface');
+        $uri = $this->createMock(UriInterface::class);
         $uri->method('getPath')->willReturn('/foo/baz');
         $uri->method('getQuery')->willReturn('');
 
-        $request = $this->createMock('Psr\Http\Message\RequestInterface');
+        $request = $this->createMock(RequestInterface::class);
         $request->method('getMethod')
             ->willReturn('GET');
         $request->method('getUri')->willReturn($uri);

Behavioral/Observer/UserObserver.php

@@ -2,25 +2,27 @@
 
 namespace DesignPatterns\Behavioral\Observer;
 
+use SplSubject;
+
 class UserObserver implements \SplObserver
 {
     /**
-     * @var User[]
+     * @var SplSubject[]
      */
     private $changedUsers = [];
 
     /**
      * It is called by the Subject, usually by SplSubject::notify()
      *
-     * @param \SplSubject $subject
+     * @param SplSubject $subject
      */
-    public function update(\SplSubject $subject)
+    public function update(SplSubject $subject)
     {
         $this->changedUsers[] = clone $subject;
     }
 
     /**
-     * @return User[]
+     * @return SplSubject[]
      */
     public function getChangedUsers(): array
     {

Behavioral/Specification/AndSpecification.php

@@ -10,7 +10,7 @@ class AndSpecification implements Specification
     private $specifications;
 
     /**
-     * @param Specification[] ...$specifications
+     * @param Specification[] $specifications
      */
     public function __construct(Specification ...$specifications)
     {

Behavioral/Specification/OrSpecification.php

@@ -10,14 +10,14 @@ class OrSpecification implements Specification
     private $specifications;
 
     /**
-     * @param Specification[] ...$specifications
+     * @param Specification[] $specifications
      */
     public function __construct(Specification ...$specifications)
     {
         $this->specifications = $specifications;
     }
 
-    /**
+    /*
      * if at least one specification is true, return true, else return false
      */
     public function isSatisfiedBy(Item $item): bool

Creational/AbstractFactory/ShippableProduct.php

@@ -5,12 +5,12 @@ namespace DesignPatterns\Creational\AbstractFactory;
 class ShippableProduct implements Product
 {
     /**
-     * @var float
+     * @var int
      */
     private $productPrice;
 
     /**
-     * @var float
+     * @var int
      */
     private $shippingCosts;
 

Creational/StaticFactory/FormatNumber.php

@@ -6,6 +6,6 @@ class FormatNumber implements Formatter
 {
     public function format(string $input): string
     {
-        return number_format($input);
+        return number_format((int) $input);
     }
 }

Creational/StaticFactory/Tests/StaticFactoryTest.php

@@ -2,6 +2,8 @@
 
 namespace DesignPatterns\Creational\StaticFactory\Tests;
 
+use DesignPatterns\Creational\StaticFactory\FormatNumber;
+use DesignPatterns\Creational\StaticFactory\FormatString;
 use DesignPatterns\Creational\StaticFactory\StaticFactory;
 use PHPUnit\Framework\TestCase;
 
@@ -9,18 +11,12 @@ class StaticFactoryTest extends TestCase
 {
     public function testCanCreateNumberFormatter()
     {
-        $this->assertInstanceOf(
-            'DesignPatterns\Creational\StaticFactory\FormatNumber',
-            StaticFactory::factory('number')
-        );
+        $this->assertInstanceOf(FormatNumber::class, StaticFactory::factory('number'));
     }
 
     public function testCanCreateStringFormatter()
     {
-        $this->assertInstanceOf(
-            'DesignPatterns\Creational\StaticFactory\FormatString',
-            StaticFactory::factory('string')
-        );
+        $this->assertInstanceOf(FormatString::class, StaticFactory::factory('string'));
     }
 
     public function testException()

More/EAV/Entity.php

@@ -2,10 +2,12 @@
 
 namespace DesignPatterns\More\EAV;
 
+use SplObjectStorage;
+
 class Entity
 {
     /**
-     * @var \SplObjectStorage
+     * @var SplObjectStorage<Value,Value>
      */
     private $values;
 
@@ -20,7 +22,7 @@ class Entity
      */
     public function __construct(string $name, $values)
     {
-        $this->values = new \SplObjectStorage();
+        $this->values = new SplObjectStorage();
         $this->name = $name;
 
         foreach ($values as $value) {

More/EAV/Value.php

@@ -24,6 +24,6 @@ class Value
 
     public function __toString(): string
     {
-        return sprintf('%s: %s', $this->attribute, $this->name);
+        return sprintf('%s: %s', (string) $this->attribute, $this->name);
     }
 }

More/ServiceLocator/ServiceLocator.php

@@ -5,18 +5,17 @@ namespace DesignPatterns\More\ServiceLocator;
 class ServiceLocator
 {
     /**
-     * @var array|Service[]
+     * @var string[][]
      */
     private $services = [];
 
     /**
-     * @var array|Service[]
+     * @var Service[]
      */
     private $instantiated = [];
 
     public function addInstance(string $class, Service $service)
     {
-        $this->services[$class] = $service;
         $this->instantiated[$class] = $service;
     }
 
@@ -55,6 +54,10 @@ class ServiceLocator
                 throw new \OutOfRangeException('Too many arguments given');
         }
 
+        if (!$object instanceof Service) {
+            throw new \InvalidArgumentException('Could not register service: is no instance of Service');
+        }
+
         $this->instantiated[$class] = $object;
 
         return $object;

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));

composer.json

@@ -16,7 +16,9 @@
     "require-dev": {
         "phpunit/phpunit": "^8",
         "squizlabs/php_codesniffer": "^3",
-        "flyeralarm/php-code-validator": "^2.2"
+        "flyeralarm/php-code-validator": "^2.2",
+        "vimeo/psalm": "^3.4",
+        "psalm/plugin-phpunit": "^0.7.0"
     },
     "autoload": {
         "psr-4": {

psalm.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0"?>
+<psalm
+    totallyTyped="false"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="Behavioral"/>
+        <directory name="Creational"/>
+        <directory name="More"/>
+        <directory name="Structural"/>
+        <ignoreFiles>
+            <directory name="vendor"/>
+        </ignoreFiles>
+    </projectFiles>
+
+    <issueHandlers>
+        <LessSpecificReturnType errorLevel="info"/>
+
+        <!-- level 3 issues - slightly lazy code writing, but provably low false-negatives -->
+
+        <DeprecatedMethod errorLevel="info"/>
+        <DeprecatedProperty errorLevel="info"/>
+        <DeprecatedClass errorLevel="info"/>
+        <DeprecatedConstant errorLevel="info"/>
+        <DeprecatedFunction errorLevel="info"/>
+        <DeprecatedInterface errorLevel="info"/>
+        <DeprecatedTrait errorLevel="info"/>
+
+        <InternalMethod errorLevel="info"/>
+        <InternalProperty errorLevel="info"/>
+        <InternalClass errorLevel="info"/>
+
+        <MissingClosureReturnType errorLevel="info"/>
+        <MissingReturnType errorLevel="info"/>
+        <MissingPropertyType errorLevel="info"/>
+        <InvalidDocblock errorLevel="info"/>
+        <MisplacedRequiredParam errorLevel="info"/>
+
+        <PropertyNotSetInConstructor errorLevel="info"/>
+        <MissingConstructor errorLevel="info"/>
+        <MissingClosureParamType errorLevel="info"/>
+        <MissingParamType errorLevel="info"/>
+
+        <RedundantCondition errorLevel="info"/>
+
+        <DocblockTypeContradiction errorLevel="info"/>
+        <RedundantConditionGivenDocblockType errorLevel="info"/>
+
+        <UnresolvableInclude errorLevel="info"/>
+
+        <RawObjectIteration errorLevel="info"/>
+
+        <InvalidStringClass errorLevel="info"/>
+    </issueHandlers>
+<plugins>
+    <pluginClass class="Psalm\PhpUnitPlugin\Plugin"/></plugins>
+</psalm>