diff --git a/image_prediction/image_extractor/extractors/parsable.py b/image_prediction/image_extractor/extractors/parsable.py
index 933b4b4..cde8cd9 100644
--- a/image_prediction/image_extractor/extractors/parsable.py
+++ b/image_prediction/image_extractor/extractors/parsable.py
@@ -7,6 +7,7 @@ from PIL import Image
 from funcy import rcompose
 
 from image_prediction.image_extractor.extractor import ImageExtractor, ImageMetadataPair
+from image_prediction.info import Info
 
 
 class ParsablePDFImageExtractor(ImageExtractor):
@@ -21,15 +22,15 @@ class ParsablePDFImageExtractor(ImageExtractor):
             x1, y1, x2, y2 = map(rounder, image_info["bbox"])
             width, height = itemgetter("width", "height")(image_info)
             return {
-                "page_width": page_width,
-                "page_height": page_height,
-                "page_idx": page.number,
-                "width": width,
-                "height": height,
-                "x1": x1,
-                "x2": x2,
-                "y1": y1,
-                "y2": y2,
+                Info.PAGE_WIDTH: page_width,
+                Info.PAGE_HEIGHT: page_height,
+                Info.PAGE_IDX: page.number,
+                Info.WIDTH: width,
+                Info.HEIGHT: height,
+                Info.X1: x1,
+                Info.X2: x2,
+                Info.Y1: y1,
+                Info.Y2: y2,
             }
 
         rounder = rcompose(round, int)
diff --git a/image_prediction/info.py b/image_prediction/info.py
new file mode 100644
index 0000000..e9083ee
--- /dev/null
+++ b/image_prediction/info.py
@@ -0,0 +1,13 @@
+from enum import Enum
+
+
+class Info(Enum):
+    PAGE_WIDTH = "page_width"
+    PAGE_HEIGHT = "page_height"
+    PAGE_IDX = "page_idx"
+    WIDTH = "width"
+    HEIGHT = "height"
+    X1 = "x1"
+    X2 = "x2"
+    Y1 = "y1"
+    Y2 = "y2"
diff --git a/image_prediction/model_loader/database/connector.py b/image_prediction/model_loader/database/connector.py
index 8b98f97..cbc4438 100644
--- a/image_prediction/model_loader/database/connector.py
+++ b/image_prediction/model_loader/database/connector.py
@@ -5,4 +5,4 @@ class DatabaseConnector(abc.ABC):
 
     @abc.abstractmethod
     def get_object(self, identifier):
-        pass
+        raise NotImplementedError
diff --git a/pytest.ini b/pytest.ini
index bae23b6..094d599 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -2,3 +2,4 @@
 norecursedirs = incl
 filterwarnings =
     ignore:.*imp.*:DeprecationWarning
+    ignore:.*Use.*:DeprecationWarning
diff --git a/test/unit_tests/conftest.py b/test/unit_tests/conftest.py
index cb8e3b2..8d21e8c 100644
--- a/test/unit_tests/conftest.py
+++ b/test/unit_tests/conftest.py
@@ -18,6 +18,7 @@ from image_prediction.exceptions import UnknownEstimatorAdapter, UnknownImageExt
 from image_prediction.image_extractor.extractor import ImageMetadataPair
 from image_prediction.image_extractor.extractors.mock import ImageExtractorMock
 from image_prediction.image_extractor.extractors.parsable import ParsablePDFImageExtractor
+from image_prediction.info import Info
 from image_prediction.model_loader.database.connectors.mock import DatabaseConnectorMock
 from image_prediction.model_loader.loader import ModelLoader
 from image_prediction.model_loader.loaders.mlflow import MlflowConnector
@@ -30,6 +31,8 @@ def image_extractor(extractor_type):
         return ImageExtractorMock()
     elif extractor_type == "parsable_pdf":
         return ParsablePDFImageExtractor()
+    elif extractor_type == "default":
+        return None
     else:
         raise UnknownImageExtractor(f"No image extractor for type {extractor_type} was specified.")
 
@@ -149,15 +152,15 @@ def metadata(images):
         y1 = random.randint(0, page_height - height)
         y2 = y1 + height
         metadata = {
-            "page_width": page_width,
-            "page_height": page_height,
-            "page_idx": current_page_idx(),
-            "width": width,
-            "height": height,
-            "x1": x1,
-            "x2": x2,
-            "y1": y1,
-            "y2": y2
+            Info.PAGE_WIDTH: page_width,
+            Info.PAGE_HEIGHT: page_height,
+            Info.PAGE_IDX: current_page_idx(),
+            Info.WIDTH: width,
+            Info.HEIGHT: height,
+            Info.X1: x1,
+            Info.X2: x2,
+            Info.Y1: y1,
+            Info.Y2: y2,
         }
         return metadata
 
@@ -180,7 +183,7 @@ def pdf(image_metadata_pairs):
 
 
 def add_image(pdf, image_metadata_pair):
-    while fewer_pages_then_required(image_metadata_pair.metadata["page_idx"], pdf):
+    while fewer_pages_then_required(image_metadata_pair.metadata[Info.PAGE_IDX], pdf):
         pdf.add_page()
 
     add_image_to_last_page(pdf, image_metadata_pair)
@@ -196,7 +199,7 @@ def pdf_stream(pdf: fpdf.fpdf.FPDF):
 
 def add_image_to_last_page(pdf: fpdf.fpdf.FPDF, image_metadata_pair):
     image, metadata = image_metadata_pair
-    x, y, w, h = itemgetter("x1", "y1", "width", "height")(metadata)
+    x, y, w, h = itemgetter(Info.X1, Info.Y1, Info.WIDTH, Info.HEIGHT)(metadata)
 
     with tempfile.NamedTemporaryFile(suffix=".png") as temp_image:
         image.save(temp_image.name)
diff --git a/test/unit_tests/image_extractor_test.py b/test/unit_tests/image_extractor_test.py
index b07d711..35cde34 100644
--- a/test/unit_tests/image_extractor_test.py
+++ b/test/unit_tests/image_extractor_test.py
@@ -3,6 +3,7 @@ import pytest
 
 from image_prediction.estimator.preprocessor.utils import images_to_batch_tensor
 from image_prediction.extraction import extract_images_from_pdf
+from image_prediction.image_extractor.extractors.parsable import ParsablePDFImageExtractor
 
 
 @pytest.mark.parametrize("extractor_type", ["mock"])
@@ -12,7 +13,7 @@ def test_image_extractor_mock(image_extractor, images):
     assert images_extracted == images
 
 
-@pytest.mark.parametrize("extractor_type", ["parsable_pdf"])
+@pytest.mark.parametrize("extractor_type", ["parsable_pdf", "default"])
 @pytest.mark.parametrize("batch_size", [0, 1, 2, 64])
 @pytest.mark.parametrize("input_size", [{"depth": 3, "width": 170, "height": 220}], indirect=["input_size"])
 def test_parsable_pdf_image_extractor(image_extractor, pdf, images, metadata, input_size):