server/docker: fix missing installation requirements

Furthermore, an update to Pillow has improved the floating-point
precision of the image hash algorithm, requiring minor updates to
the respective unit tests.

See https://github.com/python-pillow/Pillow/pull/4320

server/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:latest
+FROM alpine:3.12
 WORKDIR /opt/app
 
 RUN \
@@ -7,6 +7,7 @@ RUN \
         dumb-init \
         ffmpeg \
         py3-waitress \
+        py3-pip \
         # from requirements.txt:
         py3-yaml \
         py3-psycopg2 \
@@ -22,7 +23,7 @@ RUN \
         alembic \
         "coloredlogs==5.0" \
         youtube-dl \
-    && exit 0
+    && apk --no-cache del py3-pip
 
 ARG PUID=1000
 ARG PGID=1000

server/hooks/test

@@ -11,6 +11,7 @@ FROM ${BASE_IMAGE}
 WORKDIR /opt/app
 USER root
 RUN apk --no-cache add \
+		py3-pip \
 		py3-pytest \
 		py3-pytest-cov \
 		postgresql \

server/requirements.txt

@@ -9,3 +9,4 @@ pillow>=4.3.0
 pynacl>=1.2.1
 pytz>=2018.3
 pyRFC3339>=1.0
+youtube-dl

server/szurubooru/tests/func/test_image_hash.py

@@ -15,7 +15,7 @@ def test_signature_functions(read_asset, config_injector):
     assert array_equal(sig2, sig2_repacked)
 
     dist1 = image_hash.normalized_distance([sig1], sig2)
-    assert abs(dist1[0] - 0.20599895341812172) < 1e-8
+    assert abs(dist1[0] - 0.19713075553164386) < 1e-8
 
     dist2 = image_hash.normalized_distance([sig2], sig2)
     assert abs(dist2[0]) < 1e-8
@@ -23,4 +23,4 @@ def test_signature_functions(read_asset, config_injector):
     words1 = image_hash.generate_words(sig1)
     words2 = image_hash.generate_words(sig2)
     words_match = sum(word1 == word2 for word1, word2 in zip(words1, words2))
-    assert words_match == 17
+    assert words_match == 18

server/szurubooru/tests/func/test_posts.py

@@ -991,7 +991,7 @@ def test_search_by_image(post_factory, config_injector, read_asset):
     result1 = posts.search_by_image(read_asset('jpeg-similar.jpg'))
     assert len(result1) == 1
     result1_distance, result1_post = result1[0]
-    assert abs(result1_distance - 0.20599895341812172) < 1e-8
+    assert abs(result1_distance - 0.19713075553164386) < 1e-8
     assert result1_post.post_id == post.post_id
 
     result2 = posts.search_by_image(read_asset('png.png'))