remove hhvm and php 5.5 support

hhvm is not even supported by composer anymore and php 5.5 long eol. this way we can also update phpunit.

.gitignore

@@ -1,11 +1,4 @@
-phpunit.xml
-composer.phar
-composer.lock
-composer-test.lock
-vendor/
-build/artifacts/
 artifacts/
-docs/_build
-docs/*.pyc
-.idea
-.DS_STORE
+vendor/
+composer.lock
+phpunit.xml

.travis.yml

@@ -1,27 +1,23 @@
 language: php
 
-sudo: false
+dist: xenial
 
 cache:
     directories:
         - $HOME/.composer/cache/files
 
 php:
-    - 5.5
     - 5.6
     - 7.0
     - 7.1
     - 7.2
     - 7.3
-    - hhvm
 
 env:
     global:
         - TEST_COMMAND="composer test"
 
 matrix:
-    allow_failures:
-        - php: hhvm
     fast_finish: true
     include:
         - php: 5.5
@@ -31,8 +27,6 @@ before_install:
     - if [[ $COVERAGE != true ]]; then phpenv config-rm xdebug.ini || true; fi
 
 install:
-    # To be removed when this issue will be resolved: https://github.com/composer/composer/issues/5355
-    - if [[ "$COMPOSER_FLAGS" == *"--prefer-lowest"* ]]; then travis_retry composer update --prefer-dist --no-interaction --prefer-stable --quiet; fi
     - travis_retry composer update ${COMPOSER_FLAGS} --prefer-dist --no-interaction
 
 script:

composer.json

@@ -11,10 +11,10 @@
         }
     ],
     "require": {
-        "php": ">=5.5.0"
+        "php": ">=5.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.36"
+        "phpunit/phpunit": "^5.7.27 || ^7.5"
     },
     "autoload": {
         "psr-4": {

phpunit.xml.dist

@@ -1,13 +1,18 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit colors="true" bootstrap="vendor/autoload.php">
+<phpunit
+    colors="true"
+    beStrictAboutOutputDuringTests="true"
+    beStrictAboutTestsThatDoNotTestAnything="false"
+    bootstrap="vendor/autoload.php"
+>
     <testsuites>
         <testsuite name="GuzzleHttp Promise Test Suite">
             <directory>tests/</directory>
         </testsuite>
     </testsuites>
     <filter>
         <whitelist>
-            <directory suffix=".php">src/</directory>
+            <directory>src/</directory>
             <exclude>
                 <directory suffix="Interface.php">src/</directory>
             </exclude>

tests/functionsTest.php

@@ -532,15 +532,13 @@ public function testAsyncPromisesWithCorrectlyYieldedValues()
         ];
 
         $promise = P\coroutine(function () use ($promises) {
-            $value = null;
             $this->assertEquals('skip', (yield new FulfilledPromise('skip')));
             foreach ($promises as $idx => $p) {
-                $value = (yield $p);
-                $this->assertEquals($value, $idx);
+                $this->assertEquals($idx, (yield $p));
                 $this->assertEquals('skip', (yield new FulfilledPromise('skip')));
             }
             $this->assertEquals('skip', (yield new FulfilledPromise('skip')));
-            yield $value;
+            yield 2;
         });
 
         $promises[0]->resolve(0);