minor #13482 Implemented check on interface implementation (jaytaph)

This PR was squashed before being merged into the 2.7 branch (closes #13482).

Discussion
----------

Implemented check on interface implementation

| Q             | A
| ------------- | ---
| Bug fix?      | Yes
| New feature?  | No
| BC breaks?    | No
| Deprecations? | No
| Tests pass?   | Yes
| Fixed tickets | #13480
| License       | MIT
| Doc PR        |

Commits
-------

2a79ace Implemented check on interface implementation

2 files changed, 16 insertions, 0 deletions

diff --git a/Core/Authentication/AuthenticationProviderManager.php b/Core/Authentication/AuthenticationProviderManager.php
index f713e8f..16de8da 100644
--- a/Core/Authentication/AuthenticationProviderManager.php
+++ b/Core/Authentication/AuthenticationProviderManager.php
@@ -48,6 +48,12 @@ class AuthenticationProviderManager implements AuthenticationManagerInterface
             throw new \InvalidArgumentException('You must at least add one authentication provider.');
         }
 
+        foreach ($providers as $provider) {
+            if (!$provider instanceof AuthenticationProviderInterface) {
+                throw new \InvalidArgumentException(sprintf('Provider "%s" must implement the AuthenticationProviderInterface.', get_class($provider)));
+            }
+        }
+
         $this->providers = $providers;
         $this->eraseCredentials = (bool) $eraseCredentials;
     }
diff --git a/Core/Tests/Authentication/AuthenticationProviderManagerTest.php b/Core/Tests/Authentication/AuthenticationProviderManagerTest.php
index df25874..cc8b7c0 100644
--- a/Core/Tests/Authentication/AuthenticationProviderManagerTest.php
+++ b/Core/Tests/Authentication/AuthenticationProviderManagerTest.php
@@ -27,6 +27,16 @@ class AuthenticationProviderManagerTest extends \PHPUnit_Framework_TestCase
         new AuthenticationProviderManager(array());
     }
 
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testAuthenticateWithProvidersWithIncorrectInterface()
+    {
+        new AuthenticationProviderManager(array(
+            new \stdClass(),
+        ));
+    }
+
     public function testAuthenticateWhenNoProviderSupportsToken()
     {
         $manager = new AuthenticationProviderManager(array(