diff --git a/composer.json b/composer.json
index e2d9a60..73274b1 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,10 @@
     },
     "require-dev": {
         "topthink/framework": "dev-master",
-        "phpunit/phpunit": "3.*"
+        "phpunit/phpunit": "4.8.*"
+    },
+    "config": {
+        "preferred-install": "dist"
     },
     "autoload": {
         "psr-4": {
diff --git a/tests/InfoTest.php b/tests/InfoTest.php
index a897883..ac900a8 100644
--- a/tests/InfoTest.php
+++ b/tests/InfoTest.php
@@ -18,14 +18,13 @@ class InfoTest extends TestCase
 
     public function testOpen()
     {
-        $this->expectException(Exception::class);
+        $this->setExpectedException(Exception::class);
         Image::open('');
     }
 
     public function testIllegal()
     {
-        $this->expectException(Exception::class);
-        $this->expectExceptionMessage('Illegal image file');
+        $this->setExpectedException(Exception::class, 'Illegal image file');
         Image::open(TEST_PATH . 'images/test.bmp');
     }