chapter3-exercise-centered-text-tests.md

Tests for WBE Chapter 3 Exercise Centered Text

This book’s page titles are centered; make your browser do the same for text between <h1 class="title"> and </h1>. Each line has to be centered individually, because different lines will have different lengths.

Tests

Testing boilerplate:

>>> import wbemocks
>>> _ = wbemocks.socket.patch().start()
>>> _ = wbemocks.ssl.patch().start()
>>> _ = wbemocks.patch_canvas()
>>> import browser

The headers mentioned in the exercise description are centered due to CSS, which is the subject of chapter 6. In this exercise, we will just treat h1 class="title" as a special centering tag. Among other things, both the open and close tags should flush lines, because it doesn't make sense to have a line where half the line is centered and the other half isn't.

Let's define some testing shortcuts:

>>> browser.WIDTH
800
>>> def test_layout(text):
...   dl = browser.Layout(browser.lex(text)).display_list
...   return wbemocks.normalize_display_list(dl)

Centering a line of text works:

>>> test_layout('<h1 class="title">center me</h1>') #doctest: +NORMALIZE_WHITESPACE
[(328.0, 21.0, 'center', Font size=16 weight=normal slant=roman style=None), 
 (440.0, 21.0, 'me', Font size=16 weight=normal slant=roman style=None)]

Encountering the opening h1 class="title" should trigger a flush.

>>> test_layout('first line<h1 class="title">center next line</h1>') #doctest: +NORMALIZE_WHITESPACE
[(13.0, 21.0, 'first', Font size=16 weight=normal slant=roman style=None), 
 (109.0, 21.0, 'line', Font size=16 weight=normal slant=roman style=None), 
 (272.0, 41.0, 'center', Font size=16 weight=normal slant=roman style=None),
 (384.0, 41.0, 'next', Font size=16 weight=normal slant=roman style=None),
 (464.0, 41.0, 'line', Font size=16 weight=normal slant=roman style=None)]

Centering should be aware of the WIDTH.

>>> browser.set_parameters(WIDTH=200)
>>> test_layout('<h1 class="title">center me</h1>') #doctest: +NORMALIZE_WHITESPACE
[(28.0, 21.0, 'center', Font size=16 weight=normal slant=roman style=None), 
 (140.0, 21.0, 'me', Font size=16 weight=normal slant=roman style=None)]

Centering should also be able to center different lines with different widths

>>> browser.set_parameters(WIDTH=800)
>>> test_layout('<h1 class="title">center me</h1><br><h1 class="title">also center me </h1>') #doctest: +NORMALIZE_WHITESPACE   
[(328.0, 21.0, 'center', Font size=16 weight=normal slant=roman style=None), 
 (440.0, 21.0, 'me', Font size=16 weight=normal slant=roman style=None), 
 (288.0, 41.0, 'also', Font size=16 weight=normal slant=roman style=None), 
 (368.0, 41.0, 'center', Font size=16 weight=normal slant=roman style=None), 
 (480.0, 41.0, 'me', Font size=16 weight=normal slant=roman style=None)]

You should be able to mix centered and normal text on different lines

>>> test_layout('<h1 class="title">center me</h1><br>do not center me<h1 class="title">but do center me</h1>') #doctest: +NORMALIZE_WHITESPACE   
[(328.0, 21.0, 'center', Font size=16 weight=normal slant=roman style=None), 
 (440.0, 21.0, 'me', Font size=16 weight=normal slant=roman style=None), 
 (13.0, 41.0, 'do', Font size=16 weight=normal slant=roman style=None), 
 (61.0, 41.0, 'not', Font size=16 weight=normal slant=roman style=None),
 (125.0, 41.0, 'center', Font size=16 weight=normal slant=roman style=None),
 (237.0, 41.0, 'me', Font size=16 weight=normal slant=roman style=None), 
 (272.0, 61.0, 'but', Font size=16 weight=normal slant=roman style=None), 
 (336.0, 61.0, 'do', Font size=16 weight=normal slant=roman style=None), 
 (384.0, 61.0, 'center', Font size=16 weight=normal slant=roman style=None),
 (496.0, 61.0, 'me', Font size=16 weight=normal slant=roman style=None)]

Ensure that the application correctly handles the transition from centered to regular text within the same sequence

>>> test_layout('<h1 class="title">center this</h1>then this is regular') #doctest: +NORMALIZE_WHITESPACE   
[(312.0, 21.0, 'center', Font size=16 weight=normal slant=roman style=None),
 (424.0, 21.0, 'this', Font size=16 weight=normal slant=roman style=None), 
 (13.0, 41.0, 'then', Font size=16 weight=normal slant=roman style=None), 
 (93.0, 41.0, 'this', Font size=16 weight=normal slant=roman style=None), 
 (173.0, 41.0, 'is', Font size=16 weight=normal slant=roman style=None), 
 (221.0, 41.0, 'regular', Font size=16 weight=normal slant=roman style=None)]