Don't test on older PHP versions

.travis.yml

@@ -1,11 +1,6 @@
-dist: precise
-
 language: php
 
 php:
-  - 5.3
-  - 5.4
-  - 5.5
   - 5.6
   - 7.0
   - 7.1

composer.json

@@ -22,7 +22,7 @@
         ]
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.8.0",
+        "phpunit/phpunit": "~5.7.0",
         "10up/wp_mock": "0.2.0"
     }
 }

tests/TestQueueManager.php

@@ -11,7 +11,7 @@ public function setUp() {
 		WP_Mock::setUp();
 
 		global $wpdb;
-		$wpdb = Mockery::mock( 'WPDB' );
+		$wpdb         = Mockery::mock( 'WPDB' );
 		$wpdb->prefix = 'wp_';
 	}
 
@@ -27,7 +27,7 @@ public function test_resolve() {
 	}
 
 	public function test_resolve_exception() {
-		$this->setExpectedException( ConnectionNotFoundException::class);
+		$this->expectException( ConnectionNotFoundException::class );
 		QueueManager::resolve( 'wibble' );
 	}
 }