Merge pull request #162 from clue-labs/php7.4

Test PHP 7.4 on Travis

Author: jsor

.travis.yml

@@ -4,6 +4,7 @@ php:
   - 7.1
   - 7.2
   - 7.3
+  - 7.4
   - nightly # ignore errors, see below
 
 # lock distro so new future defaults will not break the build

tests/DeferredTest.php

@@ -37,6 +37,8 @@ public function shouldRejectWithoutCreatingGarbageCyclesIfCancellerRejectsWithEx
     public function shouldRejectWithoutCreatingGarbageCyclesIfParentCancellerRejectsWithException()
     {
         gc_collect_cycles();
+        gc_collect_cycles(); // clear twice to avoid leftovers in PHP 7.4 with ext-xdebug and code coverage turned on
+
         $deferred = new Deferred(function ($resolve, $reject) {
             $reject(new \Exception('foo'));
         });
@@ -50,6 +52,8 @@ public function shouldRejectWithoutCreatingGarbageCyclesIfParentCancellerRejects
     public function shouldRejectWithoutCreatingGarbageCyclesIfCancellerHoldsReferenceAndExplicitlyRejectWithException()
     {
         gc_collect_cycles();
+        gc_collect_cycles(); // clear twice to avoid leftovers in PHP 7.4 with ext-xdebug and code coverage turned on
+
         $deferred = new Deferred(function () use (&$deferred) { });
         $deferred->reject(new \Exception('foo'));
         unset($deferred);