diff --git a/src/documents/management/commands/document_thumbnails.py b/src/documents/management/commands/document_thumbnails.py
index 01df14624..6f6451599 100644
--- a/src/documents/management/commands/document_thumbnails.py
+++ b/src/documents/management/commands/document_thumbnails.py
@@ -13,8 +13,14 @@ from ...parsers import get_parser_class_for_mime_type
 
 def _process_document(doc_in):
     document = Document.objects.get(id=doc_in)
-    parser = get_parser_class_for_mime_type(document.mime_type)(
-        logging_group=None)
+    parser_class = get_parser_class_for_mime_type(document.mime_type)
+
+    if parser_class:
+        parser = parser_class(logging_group=None)
+    else:
+        print(f"{document} No parser for mime type {document.mime_type}")
+        return
+
     try:
         thumb = parser.get_optimised_thumbnail(
             document.source_path, document.mime_type)
diff --git a/src/documents/tests/test_management_thumbnails.py b/src/documents/tests/test_management_thumbnails.py
new file mode 100644
index 000000000..7ecdf0489
--- /dev/null
+++ b/src/documents/tests/test_management_thumbnails.py
@@ -0,0 +1,52 @@
+import os
+import shutil
+from unittest import mock
+
+from django.core.management import call_command
+from django.test import TestCase
+
+from documents.management.commands.document_thumbnails import _process_document
+from documents.models import Document, Tag, Correspondent, DocumentType
+from documents.tests.utils import DirectoriesMixin
+
+
+class TestMakeThumbnails(DirectoriesMixin, TestCase):
+
+    def make_models(self):
+        self.d1 = Document.objects.create(checksum="A", title="A", content="first document", mime_type="application/pdf", filename="test.pdf")
+        shutil.copy(os.path.join(os.path.dirname(__file__), "samples", "simple.pdf"), self.d1.source_path)
+
+        self.d2 = Document.objects.create(checksum="Ass", title="A", content="first document", mime_type="application/pdf", filename="test2.pdf")
+        shutil.copy(os.path.join(os.path.dirname(__file__), "samples", "simple.pdf"), self.d2.source_path)
+
+    def setUp(self) -> None:
+        super(TestMakeThumbnails, self).setUp()
+        self.make_models()
+
+    def test_process_document(self):
+        self.assertFalse(os.path.isfile(self.d1.thumbnail_path))
+        _process_document(self.d1.id)
+        self.assertTrue(os.path.isfile(self.d1.thumbnail_path))
+
+    @mock.patch("documents.management.commands.document_thumbnails.shutil.move")
+    def test_process_document_invalid_mime_type(self, m):
+        self.d1.mime_type = "asdasdasd"
+        self.d1.save()
+
+        _process_document(self.d1.id)
+
+        m.assert_not_called()
+
+    def test_command(self):
+        self.assertFalse(os.path.isfile(self.d1.thumbnail_path))
+        self.assertFalse(os.path.isfile(self.d2.thumbnail_path))
+        call_command('document_thumbnails')
+        self.assertTrue(os.path.isfile(self.d1.thumbnail_path))
+        self.assertTrue(os.path.isfile(self.d2.thumbnail_path))
+
+    def test_command_documentid(self):
+        self.assertFalse(os.path.isfile(self.d1.thumbnail_path))
+        self.assertFalse(os.path.isfile(self.d2.thumbnail_path))
+        call_command('document_thumbnails', '-d', f"{self.d1.id}")
+        self.assertTrue(os.path.isfile(self.d1.thumbnail_path))
+        self.assertFalse(os.path.isfile(self.d2.thumbnail_path))