Added test for each case

.gitignore

@@ -1,4 +1,4 @@
 /vendor
 /composer.lock
-/build_test
+/build
 .php_cs.cache

phpunit.xml.dist

@@ -37,6 +37,8 @@
             <directory>./src</directory>
             <exclude>
                 <directory>./src/bootstrap.php</directory>
+                <directory>./src/BackslashFixer/Console</directory>
+                <directory>./src/BackslashFixer/Command</directory>
             </exclude>
         </whitelist>
     </filter>

src/BackslashFixer/Command/FixerCommand.php

@@ -54,7 +54,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $fileEditor = new FileEditor(new FileGenerator(), new FunctionRepository(), $fileSystem);
 
         foreach ($fileSystem->getFilesFromPath($path) as $file) {
-            $fileEditor->addBackslashesToFunctions($file);
+            $fileEditor->addBackslashes($file);
         }
 
         $output->write('Success!', \true);

src/BackslashFixer/Fixer/FileEditor.php

@@ -46,9 +46,9 @@ public function __construct(
 
     /**
      * @param $path
-     * @return float
+     * @return void
      */
-    public function addBackslashesToFunctions($path)
+    public function addBackslashes($path)
     {
         $generator = $this->fileGenerator->fromReflectedFileName($path);
         $source = $generator->getSourceContent();
@@ -76,7 +76,7 @@ public function addBackslashesToFunctions($path)
      *
      * @return array
      */
-    public function removeFunctionsExistingInCurrentNamespaceFromBackslashing(
+    private function removeFunctionsExistingInCurrentNamespaceFromBackslashing(
         FileGenerator $generator,
         array $functions
     ) {
@@ -102,7 +102,7 @@ public function removeFunctionsExistingInCurrentNamespaceFromBackslashing(
      *
      * @return array
      */
-    public function removeUseFunctionsFromBackslashing(FileGenerator $generator, array $functions)
+    private function removeUseFunctionsFromBackslashing(FileGenerator $generator, array $functions)
     {
         foreach ($generator->getUses() as $namespacedFunction) {
             list($functionOrClass, $alias) = $namespacedFunction;

tests/Fixer/FileEditorTest.php

@@ -0,0 +1,80 @@
+<?php
+/**
+ * Author: Nil Portugués Calderó <contact@nilportugues.com>
+ * Date: 11/4/15
+ * Time: 8:03 PM
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace NilPortugues\Tests\BackslashFixer\Fixer;
+
+use NilPortugues\BackslashFixer\Fixer\FileEditor;
+use NilPortugues\BackslashFixer\Fixer\FunctionRepository;
+use Zend\Code\Generator\FileGenerator;
+
+
+/**
+ * Class FileEditorTest
+ * @package NilPortugues\Tests\BackslashFixer\Fixer
+ */
+class FileEditorTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var FileEditor
+     */
+    protected $fileEditor;
+
+    /**
+     * @var InMemoryFileSystem
+     */
+    protected $fileSystem;
+
+    /**
+     * @var string
+     */
+    protected $base;
+
+    protected function setUp()
+    {
+        $reflector = new \ReflectionClass(get_class($this));
+        $this->base =  dirname($reflector->getFileName());
+
+        $this->fileSystem = new InMemoryFileSystem();
+
+        $this->fileEditor = new FileEditor(
+            new FileGenerator(),
+            new FunctionRepository(),
+            $this->fileSystem
+        );
+    }
+
+    public function testItCanBackSlashBooleansAndAndNull()
+    {
+        $this->fileEditor->addBackslashes($this->base.'/Resources/BooleanAndNull.php');
+        $output = $this->fileSystem->getFile($this->base.'/Resources/BooleanAndNull.php');
+
+        $this->assertContains('\true', $output);
+        $this->assertContains('\false', $output);
+        $this->assertContains('\null', $output);
+
+    }
+
+    public function testItCanBackSlashConstants()
+    {
+        $this->fileEditor->addBackslashes($this->base.'/Resources/Constant.php');
+        $output = $this->fileSystem->getFile($this->base.'/Resources/Constant.php');
+
+        $this->assertContains('$this->a = self::DIRECTORY_SEPARATOR;', $output);
+        $this->assertContains('$this->b = \DIRECTORY_SEPARATOR;', $output);
+    }
+
+    public function testItCanBackSlashFunctions()
+    {
+        $this->fileEditor->addBackslashes($this->base.'/Resources/Function.php');
+        $output = $this->fileSystem->getFile($this->base.'/Resources/Function.php');
+
+        $this->assertContains('return \strlen($string)', $output);
+    }
+} 

tests/NilPortugues/Tests/BackslashFixer/Fixer/InMemoryFileSystem.php → tests/Fixer/InMemoryFileSystem.php

@@ -4,7 +4,6 @@
 
 use NilPortugues\BackslashFixer\Fixer\Interfaces\FileSystem;
 
-
 class InMemoryFileSystem implements FileSystem
 {
     /**
@@ -21,22 +20,39 @@ class InMemoryFileSystem implements FileSystem
         "Resources/BooleanAndNull.php",
     ];
 
+    private $base;
+
     /**
      * InMemoryFileSystem constructor.
      */
     public function __construct()
     {
+        $reflector = new \ReflectionClass(get_class($this));
+        $this->base =  dirname($reflector->getFileName());
+
         foreach(self::$filePath as $file) {
-            self::$fileSystem[$file] = \file_get_contents($file);
+            $path = $this->base.DIRECTORY_SEPARATOR.$file;
+            self::$fileSystem[$path] = \file_get_contents($path);
         }
     }
 
+    public function getFile($file)
+    {
+        return self::$fileSystem[$file];
+    }
+
     /**
      * @inheritDoc
      */
     public function getFilesFromPath($path)
     {
-       return array_keys(self::$fileSystem);
+        $files = [];
+        foreach(array_keys(self::$fileSystem) as $file) {
+            $path = $this->base.DIRECTORY_SEPARATOR.$file;
+            $files[$path] = $path;
+        }
+
+        return $files;
     }
 
     /**