bindery/tests/test_pages.py

"""The page estimate of a document and of a built epub."""

import zipfile

import pytest

from bindery import pages
from bindery.epub import EpubError, spine_documents
from bindery.pages import Measure

TEXT = ["One line of the story.", "Another, longer line of the story that goes on for a while.", "The end."]
CHARS = sum(map(len, TEXT))


def test_a_paragraph_is_text_after_a_block_or_a_line_break():
    assert pages.measure("<p>One</p><p>Two</p>") == Measure(2, 6)
    assert pages.measure("<div>One<br/><br/>Two<br>Three</div>") == Measure(3, 11)
    assert pages.measure("<div><div>One</div><div>Two</div></div>") == Measure(2, 6)
    # Text before, between and after the blocks of an element counts too.
    assert pages.measure("<div>Intro<p>One</p>Middle<p>Two</p>End</div>") == Measure(5, 20)
    assert pages.measure("<h3>Title</h3><ul><li>One</li><li>Two</li></ul><blockquote>Three</blockquote>") == Measure(
        4, 16
    )


@pytest.mark.parametrize(
    "book",
    [
        "".join(f"<p>{line}</p>" for line in TEXT),
        "".join(f'<p class="a">{line}</p>\n' for line in TEXT),
        "<div>" + "".join(f"<div>{line}</div>" for line in TEXT) + "</div>",
        "<div>" + "<br/><br/>".join(TEXT) + "</div>",
        "<div>" + "<br>\n".join(TEXT) + "</div>",
        f"<div>{TEXT[0]}<p>{TEXT[1]}</p>{TEXT[2]}</div>",
    ],
)
def test_the_same_text_gives_the_same_measure_in_each_markup(book):
    assert pages.measure(book) == Measure(3, CHARS)


def test_inline_elements_and_table_cells_stay_in_the_line():
    assert pages.measure('<p>ab<b>cd</b><a href="x">ef</a> <span><i>gh</i></span></p>') == Measure(1, 9)
    assert pages.measure("<table><tr><td>Name</td><td>Value</td></tr><tr><th>a</th><td>b</td></tr></table>") == Measure(
        2, 11
    )
    assert pages.measure('<p>Before<img src="a.png"/>after</p>') == Measure(1, 11)


def test_only_the_text_of_the_book_counts():
    document = (
        '<?xml version="1.0"?><html><head><title>Hidden title</title><style>p { color: red }</style>'
        '<link href="a.css"/></head><body><script>var hidden;</script><script src="x.js"/>'
        "<!-- a note --><p>Shown &amp; counted</p>\n\n<p> </p><p></p></body></html>"
    )
    assert pages.measure(document) == Measure(1, len("Shown & counted"))
    assert pages.measure("") == Measure(0, 0)
    assert pages.measure("<p>\n</p>") == Measure(0, 0)


def test_a_paragraph_that_only_spaces_the_text_is_not_counted():
    spaced = "<p>One</p><p>&nbsp;</p><p>\xa0</p><p> &#160; </p><p><br/></p><p><span>&nbsp;</span></p><p>Two</p>"
    assert pages.measure(spaced) == pages.measure("<p>One</p><p>Two</p>") == Measure(2, 6)
    assert pages.measure("<div>One<br/>&nbsp;<br/>Two</div>") == Measure(2, 6)
    # A no-break space inside a paragraph is a character of its text.
    assert pages.measure("<p>One&nbsp;<b>two</b>\xa0three</p>") == Measure(1, 13)


def test_a_page_is_31_lines_and_a_line_is_a_paragraph_or_70_characters():
    assert pages.page_count(Measure(62, 620)) == (62 + 620 // 70) // 31 == 2
    assert pages.page_count(Measure(31 * 9, 31 * 9)) == 9
    assert pages.page_count(Measure(1000, 177_000)) == (1000 + 177_000 // 70) // 31


def test_a_short_book_has_one_page_and_a_book_with_no_text_has_none():
    assert pages.page_count(Measure(1, 10)) == 1
    assert pages.page_count(Measure(30, 30)) == 1
    assert pages.page_count(Measure()) == 0
    # One block of text: 2400 characters start the second page before 31 lines do.
    assert pages.page_count(Measure(1, 2399)) == 1
    assert pages.page_count(Measure(1, 2400)) == 2


def epub(path, documents, spine=None):
    names = [f"file {n}.xhtml" for n in range(len(documents))]
    items = "".join(f'<item id="f{n}" href="{name.replace(" ", "%20")}"/>' for n, name in enumerate(names))
    items += '<item id="css" href="stylesheet.css"/>'
    refs = "".join(f'<itemref idref="f{n}"/>' for n in (spine or range(len(documents))))
    with zipfile.ZipFile(path, "w") as z:
        z.writestr(
            "META-INF/container.xml",
            '<container xmlns="urn:oasis:names:tc:opendocument:xmlns:container"><rootfiles>'
            '<rootfile full-path="OEBPS/content.opf"/></rootfiles></container>',
        )
        z.writestr(
            "OEBPS/content.opf",
            f'<package xmlns="http://www.idpf.org/2007/opf"><metadata/><manifest>{items}</manifest>'
            f"<spine>{refs}</spine></package>",
        )
        z.writestr("OEBPS/stylesheet.css", "p { margin: 0 }")
        for name, document in zip(names, documents, strict=True):
            z.writestr(f"OEBPS/{name}", document)
    return path


def test_an_epub_is_counted_from_the_documents_of_its_spine(tmp_path):
    chapter = "<html><head><title>T</title></head><body>" + "<p>x</p>" * 31 + "</body></html>"
    book = epub(tmp_path / "book.epub", [chapter, "<html><body><p>Not in the spine</p></body></html>", chapter], [2, 0])
    assert spine_documents(book) == [chapter, chapter]
    # 62 paragraphs of one character.
    assert pages.epub_pages(book) == 2
    assert pages.epub_pages(epub(tmp_path / "empty.epub", ["<html><body><img src='a.png'/></body></html>"])) == 0


def test_a_file_that_is_not_an_epub_cannot_be_counted(tmp_path):
    path = tmp_path / "bad.epub"
    path.write_bytes(b"not a zip")
    with pytest.raises(EpubError):
        pages.epub_pages(path)
    with zipfile.ZipFile(path, "w") as z:
        z.writestr("META-INF/container.xml", "<container/>")
    with pytest.raises(EpubError):
        pages.epub_pages(path)