From 2c908162f1e6fc96fd212074e3b50a6f1c035403 Mon Sep 17 00:00:00 2001
From: Matthias Bisping <matthias.bisping@iqser.com>
Date: Tue, 5 Apr 2022 16:31:57 +0200
Subject: [PATCH] refactoring

---
 .../image_extractor/extractors/parsable.py    | 19 +++++++++----------
 test/unit_tests/image_extractor_test.py       | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/image_prediction/image_extractor/extractors/parsable.py b/image_prediction/image_extractor/extractors/parsable.py
index b70b0d9..9c2e10a 100644
--- a/image_prediction/image_extractor/extractors/parsable.py
+++ b/image_prediction/image_extractor/extractors/parsable.py
@@ -36,6 +36,13 @@ def get_page_metadata(page):
         Info.PAGE_IDX: page.number,
     }
 
+
+def extract_pages(doc, page_range):
+    page_range = range(page_range.start + 1, page_range.stop + 1)
+    pages = map(doc.load_page, page_range)
+    return pages
+
+
 class ParsablePDFImageExtractor(ImageExtractor):
     def __init__(self, verbose=False):
         self.doc: fitz.fitz.Document = None
@@ -44,10 +51,7 @@ class ParsablePDFImageExtractor(ImageExtractor):
     def __process_images_on_page(self, page: fitz.fitz.Page):
         def load_image_from_xref(xref):
             maybe_image = self.doc.extract_image(xref)
-            if maybe_image:
-                return Image.open(io.BytesIO(maybe_image["image"]))
-            else:
-                return None
+            return Image.open(io.BytesIO(maybe_image["image"])) if maybe_image else None
 
         image_infos = page.get_image_info(xrefs=True)
         xrefs = map(itemgetter("xref"), image_infos)
@@ -60,12 +64,7 @@ class ParsablePDFImageExtractor(ImageExtractor):
     def extract(self, pdf: bytes, page_range: range = None):
         self.doc = fitz.Document(stream=pdf)
 
-        if page_range:
-            page_range = range(page_range.start + 1, page_range.stop + 1)
-            doc = fitz.Document(stream=pdf)
-            pages = map(doc.load_page, page_range)
-        else:
-            pages = self.doc
+        pages = extract_pages(self.doc, page_range) if page_range else self.doc
 
         image_metadata_pairs = chain.from_iterable(
             map(
diff --git a/test/unit_tests/image_extractor_test.py b/test/unit_tests/image_extractor_test.py
index a6cdb3a..3c72354 100644
--- a/test/unit_tests/image_extractor_test.py
+++ b/test/unit_tests/image_extractor_test.py
@@ -1,8 +1,12 @@
+import random
+
+import fitz
 import numpy as np
 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 extract_pages
 
 
 @pytest.mark.parametrize("extractor_type", ["mock"])
@@ -18,3 +22,18 @@ def test_parsable_pdf_image_extractor(image_extractor, pdf, images, metadata, in
     images_extracted, metadata_extracted = map(list, extract_images_from_pdf(pdf, image_extractor))
     assert np.allclose(images_to_batch_tensor(images_extracted), images_to_batch_tensor(images))
     assert list(metadata_extracted) == metadata
+
+
+@pytest.mark.parametrize("batch_size", [1, 2, 16])
+def test_extract_pages(pdf):
+    doc = fitz.Document(stream=pdf)
+
+    max_index = max(0, doc.page_count - 1)
+    i = random.randint(0, max(0, max_index - 1))
+    j = random.randint(i + 1, max_index) if max_index > 0 else 0
+
+    page_range = range(i, j)
+
+    pages = list(extract_pages(doc, page_range))
+    assert all((isinstance(p, fitz.Page) for p in pages))
+    assert len(pages) == len(page_range)