diff --git a/tests/Sabre/CalDAV/Backend/AbstractPDOTestCase.php b/tests/Sabre/CalDAV/Backend/AbstractPDOTestCase.php
index 8b6de11539..3209366ad2 100644
--- a/tests/Sabre/CalDAV/Backend/AbstractPDOTestCase.php
+++ b/tests/Sabre/CalDAV/Backend/AbstractPDOTestCase.php
@@ -903,6 +903,72 @@ public function testCalendarQueryTimeRangeNotSpecified()
         self::assertTrue(in_array('event2', $result));
     }
 
+    public function testCalendarQueryGH1000()
+    {
+        $backend = new PDO($this->pdo);
+        $backend->createCalendarObject([1, 1], 'event1', <<<EOF
+            BEGIN:VCALENDAR
+            VERSION:2.0
+            BEGIN:VEVENT
+            UID:event1
+            DTSTAMP:20120418T152519Z
+            DTSTART;VALUE=DATE:20120330
+            DTEND;VALUE=DATE:20120531
+            SEQUENCE:1
+            SUMMARY:Birthday1
+            BEGIN:VALARM
+            ACTION:EMAIL
+            ATTENDEE:MAILTO:xxx@domain.de
+            TRIGGER;VALUE=DATE-TIME:20120329T060000Z
+            END:VALARM
+            END:VEVENT
+            END:VCALENDAR
+            EOF
+        );
+        $backend->createCalendarObject([1, 1], 'event2', <<<EOF
+            BEGIN:VCALENDAR
+            VERSION:2.0
+            BEGIN:VEVENT
+            UID:event2
+            DTSTAMP:20120418T152519Z
+            DTSTART;VALUE=DATE:20120330
+            DTEND;VALUE=DATE:20120531
+            SEQUENCE:1
+            SUMMARY:Birthday2
+            END:VEVENT
+            END:VCALENDAR
+            EOF
+        );
+
+        $filters = [
+            'name' => 'VCALENDAR',
+            'is-not-defined' => false,
+            'comp-filters' => [
+                [
+                    'name' => 'VEVENT',
+                    'is-not-defined' => false,
+                    'comp-filters' => [
+                        [
+                            'name' => 'VALARM',
+                            'is-not-defined' => true,
+                            'comp-filters' => [],
+                            'prop-filters' => [],
+                            'time-range' => null,
+                        ],
+                    ],
+                    'prop-filters' => [],
+                    'time-range' => false,
+                ],
+            ],
+            'prop-filters' => [],
+            'time-range' => null,
+        ];
+
+        $result = $backend->calendarQuery([1, 1], $filters);
+        self::assertFalse(in_array('event1', $result));
+        self::assertTrue(in_array('event2', $result));
+    }
+
     public function testGetChanges()
     {
         $backend = new PDO($this->pdo);
diff --git a/tests/Sabre/CalDAV/Issue1000Test.php b/tests/Sabre/CalDAV/Issue1000Test.php
new file mode 100644
index 0000000000..de312d9a83
--- /dev/null
+++ b/tests/Sabre/CalDAV/Issue1000Test.php
@@ -0,0 +1,99 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Sabre\CalDAV;
+
+use Sabre\HTTP;
+
+/**
+ * This unittest for https://github.com/sabre-io/dav/issues/1000.
+ *
+ * @copyright Copyright (C) fruux GmbH (https://fruux.com/)
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class Issue1000Test extends \Sabre\AbstractDAVServerTestCase
+{
+    protected $setupCalDAV = true;
+
+    protected $caldavCalendars = [
+        [
+            'id' => 1,
+            'name' => 'Calendar',
+            'principaluri' => 'principals/user1',
+            'uri' => 'calendar1',
+        ],
+    ];
+
+    protected $caldavCalendarObjects = [
+        1 => [
+            'event1.ics' => [
+                'calendardata' => 'BEGIN:VCALENDAR
+VERSION:2.0
+BEGIN:VEVENT
+UID:1111
+DTSTAMP:20120418T152519Z
+DTSTART;VALUE=DATE:20120330
+DTEND;VALUE=DATE:20120531
+SEQUENCE:1
+SUMMARY:Birthday1
+TRANSP:TRANSPARENT
+BEGIN:VALARM
+ACTION:EMAIL
+ATTENDEE:MAILTO:xxx@domain.de
+TRIGGER;VALUE=DATE-TIME:20120329T060000Z
+END:VALARM
+END:VEVENT
+END:VCALENDAR
+',
+            ],
+            'event2.ics' => [
+                'calendardata' => 'BEGIN:VCALENDAR
+VERSION:2.0
+BEGIN:VEVENT
+UID:1234
+DTSTAMP:20120418T152519Z
+DTSTART;VALUE=DATE:20120330
+DTEND;VALUE=DATE:20120531
+SEQUENCE:1
+SUMMARY:Birthday2
+TRANSP:TRANSPARENT
+END:VEVENT
+END:VCALENDAR
+',
+            ],
+        ],
+    ];
+
+    public function testIssue211()
+    {
+        $request = HTTP\Sapi::createFromServerArray([
+            'REQUEST_METHOD' => 'REPORT',
+            'HTTP_CONTENT_TYPE' => 'application/xml',
+            'REQUEST_URI' => '/calendars/user1/calendar1',
+            'HTTP_DEPTH' => '1',
+        ]);
+
+        $request->setBody('<?xml version="1.0" encoding="utf-8" ?>
+<C:calendar-query xmlns:D="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+    <D:prop>
+        <D:getetag/>
+    </D:prop>
+    <C:filter>
+        <C:comp-filter name="VCALENDAR">
+            <C:comp-filter name="VEVENT">
+                <C:comp-filter name="VALARM">
+                    <C:is-not-defined/>
+                </C:comp-filter>
+            </C:comp-filter>
+        </C:comp-filter>
+    </C:filter>
+</C:calendar-query>');
+
+        $response = $this->request($request);
+
+        self::assertTrue(strpos($response->getBodyAsString(), 'event2.ics') > 0);
+        self::assertTrue(false === strpos($response->getBodyAsString(), 'event1.ics'));
+    }
+}