Fix Jobs test (#19)

Fix test and add an extra check for blank responses, to make it easier
to spot problems like this in the future.

Author: danmichaelo

spec/Conf/JobsSpec.php

@@ -3,6 +3,7 @@
 namespace spec\Scriptotek\Alma\Conf;
 
 use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
 use Scriptotek\Alma\Client as AlmaClient;
 use Scriptotek\Alma\Conf\Job;
 use spec\Scriptotek\Alma\SpecHelper;
@@ -12,8 +13,6 @@ class JobsSpec extends ObjectBehavior
     public function let(AlmaClient $client)
     {
         $this->beConstructedWith($client);
-        $client->getJSON('/conf/jobs')
-            ->willReturn(SpecHelper::getDummyData('jobs_response.json'));
     }
 
     public function it_provides_a_lazy_interface_to_job_objects(AlmaClient $client)
@@ -27,8 +26,12 @@ public function it_provides_a_lazy_interface_to_job_objects(AlmaClient $client)
         $job->job_id->shouldBe($job_id);
     }
 
-    public function it_provides_jobs()
+    public function it_provides_jobs(AlmaClient $client)
     {
+        $client->getJSON(Argument::containingString('/conf/jobs?'))
+            ->shouldBeCalled()
+            ->willReturn(SpecHelper::getDummyData('jobs_response.json'));
+
         $this->all()->shouldBeArray();
         $this->all()[0]->shouldBeAnInstanceOf(Job::class);
     }

src/Model/SimplePaginatedList.php

@@ -24,10 +24,16 @@ protected function fetchBatch()
             return;
         }
 
-        $response = $this->client->getJSON($this->url('', [
+        $url = $this->url('', [
             'offset' => $this->offset,
             'limit'  => $this->limit,
-        ]));
+        ]);
+
+        $response = $this->client->getJSON($url);
+
+        if (is_null($response)) {
+            throw new \RuntimeException("Empty response from URL: $url");
+        }
 
         return $this->onData($response);
     }