diff --git a/tests/Pager_Test.php b/tests/Pager_Test.php
index f4f29a01..ccf48792 100644
--- a/tests/Pager_Test.php
+++ b/tests/Pager_Test.php
@@ -7,6 +7,7 @@ final class PagerTest extends RecurlyTestCase
     public function setUp(): void
     {
         parent::setUp();
+        $this->client = new MockClient();
 
         $this->count = 3;
         $client_stub = $this->createMock(\Recurly\BaseClient::class);
@@ -34,35 +35,61 @@ public function setUp(): void
         $this->pager = new \Recurly\Pager($client_stub, 'page_one');
     }
 
+    public function testMapArrayParams(): void
+    {
+        $ids = ['id-1', 'id-2'];
+        $idsCsv = join('%2C', $ids);
+        $url = "https://v3.recurly.com/resources?ids=$idsCsv";
+        $result = '{"object":"list","has_more":true,"next":"page_two","data":[{"object":"test_resource","name":"resource one"}]}';
+        $this->client->addScenario("GET", $url, NULL, $result, "200 OK");
+
+        $pager = new \Recurly\Pager($this->client, '/resources', ['ids' => $ids]);
+        $pager->rewind();
+        $this->assertInstanceOf(\Recurly\Response::class, $pager->getResponse());
+    }
+
     public function testGetResponse(): void
     {
-        $this->pager->rewind();
-        $this->assertInstanceOf(\Recurly\Response::class, $this->pager->getResponse());
+        $url = "https://v3.recurly.com/resources";
+        $result = '{"object":"list","has_more":false,"next":null,"data":[{"object":"test_resource","name":"resource one"}]}';
+        $this->client->addScenario("GET", $url, NULL, $result, "200 OK");
+
+        $pager = new \Recurly\Pager($this->client, '/resources');
+        $pager->rewind();
+        $this->assertInstanceOf(\Recurly\Response::class, $pager->getResponse());
     }
 
     public function testGetFirst(): void
     {
+        $url = "https://v3.recurly.com/resources?limit=1";
+        $result = '{"object":"list","has_more":true,"next":"page_two","data":[{"object":"test_resource","name":"resource one"}]}';
+        $this->client->addScenario("GET", $url, NULL, $result, "200 OK");
+
+        $pager = new \Recurly\Pager($this->client, '/resources');
         $this->assertInstanceOf(
             \Recurly\Resources\TestResource::class,
-            $this->pager->getFirst()
+            $pager->getFirst()
         );
     }
 
     public function testGetFirstNoResults(): void
     {
-        $json_string = $this->fixtures->loadJsonFixture('page_limit_1_empty', ['type' => 'string']);
-        $response = new \Recurly\Response($json_string);
-        $response->setHeaders(array('HTTP/1.1 200 OK'));
-        $client_stub = $this->createMock(\Recurly\BaseClient::class);
-        $client_stub->method('nextPage')->willReturn($response->toResource());
-        $pager = new \Recurly\Pager($client_stub, 'page_one');
+        $url = "https://v3.recurly.com/resources?limit=1";
+        $result = '{"object":"list","has_more":false,"next":null,"data":[]}';
+        $this->client->addScenario("GET", $url, NULL, $result, "200 OK");
 
+        $pager = new \Recurly\Pager($this->client, '/resources');
         $this->assertNull($pager->getFirst());
     }
 
     public function testGetCount(): void
     {
-        $this->assertEquals($this->count, $this->pager->getCount());
+        $url = "https://v3.recurly.com/resources";
+        $this->client->addScenario("HEAD", $url, NULL, '', "200 OK", ['Recurly-Total-Records' => 3]);
+
+        $pager = new \Recurly\Pager($this->client, '/resources');
+
+        $this->assertEquals($this->count, $pager->getCount());
     }
 
     public function testGetResponseChanges(): void
diff --git a/tests/mock_client.php b/tests/mock_client.php
index f0f371ec..98144808 100644
--- a/tests/mock_client.php
+++ b/tests/mock_client.php
@@ -52,9 +52,9 @@ public function deleteResource(string $resource_id): \Recurly\EmptyResource
         return $this->makeRequest('DELETE', $path, null, null);
     }
 
-    public function addScenario($method, $url, $body, $result, $status): void
+    public function addScenario($method, $url, $body, $result, $status, $additional_headers = []): void
     {
-        $resp_header = self::_generateRespHeader($status);
+        $resp_header = self::_generateRespHeader($status, $additional_headers);
         $this->http->method('execute')->with(
             $method,
             $url,
@@ -68,20 +68,25 @@ public function clearScenarios(): void
         $this->http = (new Generator())->getMock(HttpAdapter::class);
     }
 
-    private static function _generateRespHeader($status): array
+    private static function _generateRespHeader($status, $additional_headers): array
     {
-        return [
-            "HTTP/1.1 $status",
-            "Date: Wed, 19 Feb 2020 17:52:05 GMT",
-            "Content-Type: application/json; charset=utf-8",
-            "Recurly-Version: recurly.v2999-01-01",
-            "X-RateLimit-Limit: 2000",
-            "X-RateLimit-Remaining: 1996",
-            "X-RateLimit-Reset: 1582135020",
-            "X-Request-Id: 567a17af7875e3ba-ATL",
-            "Server: cloudflare",
-            "CF-RAY: 567a17af7875e3ba-ATL"
-        ];
+        $header_map = array_merge([
+            "Date" => "Wed, 19 Feb 2020 17:52:05 GMT",
+            "Content-Type" => "application/json; charset=utf-8",
+            "Recurly-Version" => "recurly.v2999-01-01",
+            "X-RateLimit-Limit" => "2000",
+            "X-RateLimit-Remaining" => "1996",
+            "X-RateLimit-Reset" => "1582135020",
+            "X-Request-Id" => "567a17af7875e3ba-ATL",
+            "Server" => "cloudflare",
+            "CF-RAY" => "567a17af7875e3ba-ATL"
+        ], $additional_headers);
+
+        $headers = ["HTTP/1.1 $status"];
+        foreach ($header_map as $k => $v) {
+            array_push($headers, "$k: $v");
+        }
+        return $headers;
     }
 
     private static function _expectedHeaders(): array