MAGETWO-37710: Setup wizard fails in readiness check when magento is deployed by composer create-project

 - Fix comment and behavior when no extension requirement is found
 - Change PhpInformation test to not duplicate tested logic

Author: monkeysee

setup/src/Magento/Setup/Model/ComposerInformation.php

@@ -39,7 +39,7 @@ public function __construct(
         Filesystem $filesystem,
         BufferIO $io
     ) {
-        // composer.json will be in same directory as vendor
+        // composer.json is in same directory as vendor
         $vendorPath = $filesystem->getDirectoryRead(DirectoryList::CONFIG)->getAbsolutePath('vendor_path.php');
         $vendorDir = require "{$vendorPath}";
         $composerJson = $filesystem->getDirectoryRead(DirectoryList::ROOT)->getAbsolutePath()
@@ -114,10 +114,6 @@ public function getRequiredExtensions()
                 $requiredExtensions[] = substr($reqIndex, 4);
             }
         }
-
-        if (!isset($requiredExtensions)) {
-            throw new \Exception('Cannot find extensions in \'composer.lock\' file');
-        }
         return array_unique($requiredExtensions);
     }
 

setup/src/Magento/Setup/Test/Unit/Model/PhpInformationTest.php

@@ -22,12 +22,11 @@ public function testGetRequiredMinimumXDebugNestedLevel()
     public function testGetCurrent()
     {
         $phpInformation = new PhpInformation();
-        $loadedExtensions = array_map('strtolower', get_loaded_extensions());
 
         // Class variable 'current' should be empty the first time
         $this->assertAttributeEmpty('current', $phpInformation);
         $actualExtensions = $phpInformation->getCurrent();
-        $this->assertEquals($loadedExtensions, $actualExtensions);
+        $this->assertTrue(is_array($actualExtensions));
 
         // Calling second type should cause class variable to be used
         $this->assertSame($actualExtensions, $phpInformation->getCurrent());