Merge pull request #122 from mbonneau/2.x_scheduler

Prevent static schedulers from being set more than once

Author: davidwdan

src/Scheduler.php

@@ -22,6 +22,9 @@ public static function getDefault(): SchedulerInterface
 
     public static function setDefault(SchedulerInterface $scheduler)
     {
+        if (static::$default !== null) {
+            throw new \Exception("Scheduler can only be set once. (Are you calling set after get?)");
+        }
         static::$default = $scheduler;
     }
 
@@ -43,11 +46,17 @@ public static function getImmediate(): ImmediateScheduler
 
     public static function setAsync($async)
     {
+        if (static::$async !== null) {
+            throw new \Exception("Scheduler can only be set once. (Are you calling set after get?)");
+        }
         self::$async = $async;
     }
 
     public static function setImmediate($immediate)
     {
+        if (static::$immediate !== null) {
+            throw new \Exception("Scheduler can only be set once. (Are you calling set after get?)");
+        }
         self::$immediate = $immediate;
     }
 }

test/Rx/SchedulerTest.php

@@ -0,0 +1,102 @@
+<?php
+
+namespace Rx;
+
+use Rx\Scheduler\EventLoopScheduler;
+use Rx\Scheduler\ImmediateScheduler;
+use Rx\Testing\TestScheduler;
+
+class SchedulerTest extends TestCase
+{
+    private function resetStaticScheduler()
+    {
+        $ref = new \ReflectionClass(Scheduler::class);
+        foreach (['default', 'async', 'immediate'] as $propertyName) {
+            $prop = $ref->getProperty($propertyName);
+            $prop->setAccessible(true);
+            $prop->setValue(null);
+            $prop->setAccessible(false);
+        }
+    }
+
+    public function setup()
+    {
+        $this->resetStaticScheduler();
+    }
+
+    public function testGetDefaultConstructsEventLoopScheduler()
+    {
+        $scheduler = Scheduler::getDefault();
+
+        $this->assertInstanceOf(EventLoopScheduler::class, $scheduler);
+    }
+
+    public function testSetDefault()
+    {
+        $scheduler = new TestScheduler();
+
+        Scheduler::setDefault($scheduler);
+
+        $this->assertSame($scheduler, Scheduler::getDefault());
+    }
+
+    public function testSetAsync()
+    {
+        $scheduler = new TestScheduler();
+
+        Scheduler::setAsync($scheduler);
+
+        $this->assertSame($scheduler, Scheduler::getAsync());
+    }
+
+    public function testSetImmediate()
+    {
+        $scheduler = new ImmediateScheduler();
+
+        Scheduler::setImmediate($scheduler);
+
+        $this->assertSame($scheduler, Scheduler::getImmediate());
+    }
+
+    /**
+     * @expectedException \Exception
+     */
+    public function testSetDefaultTwiceThrowsException()
+    {
+        $scheduler = new TestScheduler();
+
+        Scheduler::setDefault($scheduler);
+
+        $scheduler2 = new TestScheduler();
+        
+        Scheduler::setDefault($scheduler2);
+    }
+
+    /**
+     * @expectedException \Exception
+     */
+    public function testSetAsyncTwiceThrowsException()
+    {
+        $scheduler = new TestScheduler();
+
+        Scheduler::setAsync($scheduler);
+
+        $scheduler2 = new TestScheduler();
+
+        Scheduler::setAsync($scheduler2);
+    }
+
+    /**
+     * @expectedException \Exception
+     */
+    public function testSetImmediateTwiceThrowsException()
+    {
+        $scheduler = new ImmediateScheduler();
+
+        Scheduler::setImmediate($scheduler);
+
+        $scheduler2 = new ImmediateScheduler();
+
+        Scheduler::setImmediate($scheduler2);
+    }
+}