image-classification-service/test/unit_tests/image_extractor_test.py

import random
from operator import itemgetter

import fitz
import fpdf
import pytest
from PIL import Image
from funcy import first, rest

from image_prediction.extraction import extract_images_from_pdf
from image_prediction.image_extractor.extractor import ImageMetadataPair
from image_prediction.image_extractor.extractors.parsable import extract_pages, get_image_infos, has_alpha_channel
from image_prediction.info import Info
from test.utils.comparison import metadata_equal, image_sets_equal
from test.utils.generation.pdf import add_image, pdf_stream


@pytest.mark.parametrize("extractor_type", ["mock"])
@pytest.mark.parametrize("batch_size", [1, 2, 16])
def test_image_extractor_mock(image_extractor, images):
    images_extracted, metadata = map(list, zip(*image_extractor(images)))
    assert images_extracted == images


@pytest.mark.parametrize("extractor_type", ["parsable_pdf", "default"])
@pytest.mark.parametrize("input_size", [{"depth": 3, "width": 170, "height": 220}], indirect=["input_size"])
@pytest.mark.parametrize("alpha", [False, True])
def test_parsable_pdf_image_extractor(image_extractor, pdf, images, metadata, input_size, alpha):
    images_extracted, metadata_extracted = map(list, extract_images_from_pdf(pdf, image_extractor))
    if not alpha:
        assert image_sets_equal(images_extracted, images)
    assert metadata_equal(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)


@pytest.mark.parametrize("suffix", ["gif", "png", "jpeg"])
@pytest.mark.parametrize("mode", ["RGB", "RGBA"])
def test_has_alpha_channel(base_patch_metadata, suffix, mode):

    mode = "RGB" if suffix == "jpeg" else mode

    pdf = fpdf.FPDF(unit="pt")

    image = Image.new(mode, itemgetter(Info.WIDTH, Info.HEIGHT)(base_patch_metadata), color=(10, 10, 10))

    add_image(pdf, ImageMetadataPair(image, base_patch_metadata), suffix=suffix)

    doc = fitz.Document(stream=pdf_stream(pdf))

    page = first(doc)

    xrefs = map(itemgetter("xref"), get_image_infos(page))

    result = has_alpha_channel(doc, first(xrefs))

    if mode == "RGBA":
        assert result
    if mode == "RGB":
        assert not result

    assert not list(rest(xrefs))

    doc.close()