build up a test scenario with guzzle async

composer.json

@@ -11,7 +11,8 @@
         "ext-redis": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "5.4.6"
+        "phpunit/phpunit": "5.4.6",
+        "guzzlehttp/guzzle": "~6.0"
     },
     "autoload": {
         "psr-0": {

examples/flush_redis.php

@@ -0,0 +1,5 @@
+<?php
+require __DIR__ . '/../vendor/autoload.php';
+
+$redisAdapter = new \Prometheus\RedisAdapter('localhost');
+$redisAdapter->flushRedis();

examples/metrics.php

@@ -0,0 +1,12 @@
+<?php
+require __DIR__ . '/../vendor/autoload.php';
+
+use Prometheus\RedisAdapter;
+use Prometheus\Registry;
+
+$redisAdapter = new RedisAdapter('localhost');
+$registry = new Registry($redisAdapter);
+$result = $registry->toText();
+
+header('Content-type: text/plain; version=0.0.4');
+echo $result;

examples/some_request_uri.php

@@ -0,0 +1,19 @@
+<?php
+require __DIR__ . '/../vendor/autoload.php';
+
+$redisAdapter = new \Prometheus\RedisAdapter('localhost');
+$registry = new \Prometheus\Registry($redisAdapter);
+$counter = $registry->registerGauge('test', 'some_gauge', 'it sets', ['type']);
+$counter->set(234, ['blue']);
+$counter->set(123, ['red']);
+
+$counter = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
+$counter->increaseBy(1, ['blue']);
+$counter->increaseBy(2, ['red']);
+
+$histogram = $registry->registerHistogram('test', 'some_histogram', 'it observes', ['type'], [1, 2, 3.5, 4]);
+$histogram->observe(2.5, ['blue']);
+
+$registry->flush();
+
+echo "OK\n";

tests/Test/BlackBoxTest.php

@@ -0,0 +1,39 @@
+<?php
+namespace Test;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\Promise;
+use PHPUnit_Framework_TestCase;
+
+class BlackBoxTest extends PHPUnit_Framework_TestCase
+{
+    /**
+     * @test
+     */
+    public function countersShouldIncrementAtomically()
+    {
+        $client = new Client(['base_uri' => 'http://localhost:8080/']);
+        $client->get('/examples/flush_redis.php');
+
+        $start = microtime(true);
+        $promises = [
+            $client->getAsync('/examples/some_request_uri.php?0'),
+            $client->getAsync('/examples/some_request_uri.php?1'),
+            $client->getAsync('/examples/some_request_uri.php?2'),
+            $client->getAsync('/examples/some_request_uri.php?3'),
+            $client->getAsync('/examples/some_request_uri.php?4'),
+            $client->getAsync('/examples/some_request_uri.php?5'),
+            $client->getAsync('/examples/some_request_uri.php?6'),
+            $client->getAsync('/examples/some_request_uri.php?7'),
+            $client->getAsync('/examples/some_request_uri.php?8'),
+            $client->getAsync('/examples/some_request_uri.php?9'),
+        ];
+
+        Promise\settle($promises)->wait();
+        $end = microtime(true);
+        echo "time: " . ($end - $start) . "\n";
+
+        $metricsResult = $client->get('/examples/metrics.php');
+        var_dump((string)$metricsResult->getBody());
+    }
+}