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chapter3-base-tests.md 5.86 KiB

Tests for WBE Chapter 3

Chapter 3 (Formatting Text) adds on font metrics and simple font styling via HTML tags. This file contains tests for the additional functionality.

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

Make sure you have the expected default values for HSTEP, VSTEP, WIDTH, and HEIGHT.

>>> browser.HSTEP
13
>>> browser.VSTEP
18
>>> browser.WIDTH
800
>>> browser.HEIGHT
600

Notes

You might need to modify the __repr__ method on Text and Tag if you factored your project into multiple files: (This is especially true if you see a mismatched output of the form <layout.Tag object at ...>)

class Text:
    ...
    def __repr__(self):
        return "Text('{}')".format(self.text)

class Tag:
    ...
    def __repr__(self):
        return "Tag('{}')".format(self.tag)

Testing lex

The lex function in chapter three has been beefed up to return an array of Tag or Text objects, rather than just the stream of characters from the input.

To allow us to print these in a readable form please add a __repr__(self): method to your Tag and Text classes. The bodies of these methods should, respectively, be return "Tag('{}')".format(self.tag) and return "Text('{}')".format(self.text)

>>> browser.lex('<body>hello</body>')
[Tag('body'), Text('hello'), Tag('/body')]
>>> browser.lex('he<body>llo</body>')
[Text('he'), Tag('body'), Text('llo'), Tag('/body')]
>>> browser.lex('he<body>l</body>lo')
[Text('he'), Tag('body'), Text('l'), Tag('/body'), Text('lo')]
>>> browser.lex('he<body>l<div>l</div>o</body>')
[Text('he'), Tag('body'), Text('l'), Tag('div'), Text('l'), Tag('/div'), Text('o'), Tag('/body')]

Note that the tags do not have to match:

>>> browser.lex('he<body>l</div>lo')
[Text('he'), Tag('body'), Text('l'), Tag('/div'), Text('lo')]
>>> browser.lex('he<body>l<div>l</body>o</div>')
[Text('he'), Tag('body'), Text('l'), Tag('div'), Text('l'), Tag('/body'), Text('o'), Tag('/div')]

Testing Layout

This chapter also creates a Layout class to output a display list that can format text. However, note that this test doesn't use real tkinter fonts, but rather a mock font that has faked metrics.

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

>>> test_layout("abc")
[(13.0, 21.0, 'abc', Font size=16 weight=normal slant=roman style=None)]

>>> test_layout("<b>abc</b>")
[(13.0, 21.0, 'abc', Font size=16 weight=bold slant=roman style=None)]

>>> test_layout("<big>abc</big>")
[(13.0, 21.75, 'abc', Font size=20 weight=normal slant=roman style=None)]

>>> test_layout("<big><big>abc</big></big>")
[(13.0, 22.5, 'abc', Font size=24 weight=normal slant=roman style=None)]

>>> test_layout("<big><big><i>abc</i></big></big>")
[(13.0, 22.5, 'abc', Font size=24 weight=normal slant=italic style=None)]

>>> test_layout("<big><big><i>abc</i></big>def</big>") #doctest: +NORMALIZE_WHITESPACE
[(13.0, 22.5, 'abc', Font size=24 weight=normal slant=italic style=None), 
 (109.0, 25.5, 'def', Font size=20 weight=normal slant=roman style=None)]

Lines of text are spaced to make room for the tallest text. Let's lay out text with mixed font sizes, and then measure the line heights:

>>> def baseline(word):
...     return word[1] + word[3].metrics("ascent")

>>> test_layout("Start<br>Regular<br>Regular <big><big>Big") #doctest: +NORMALIZE_WHITESPACE 
[(13.0, 21.0, 'Start', Font size=16 weight=normal slant=roman style=None), 
 (13.0, 41.0, 'Regular', Font size=16 weight=normal slant=roman style=None),
 (13.0, 68.5, 'Regular', Font size=16 weight=normal slant=roman style=None), 
 (141.0, 62.5, 'Big', Font size=24 weight=normal slant=roman style=None)]

>>> display_list = test_layout("Start<br>Regular<br>Regular <big><big>Big")
>>> baseline(display_list[1]) - baseline(display_list[0])
20.0
>>> baseline(display_list[3]) - baseline(display_list[1])
27.5

The differing line heights don't occur when text gets smaller:

>>> test_layout("Start<br>Regular<br>Regular <small><small>Small")  #doctest: +NORMALIZE_WHITESPACE 
[(13.0, 21.0, 'Start', Font size=16 weight=normal slant=roman style=None),
 (13.0, 41.0, 'Regular', Font size=16 weight=normal slant=roman style=None),
 (13.0, 61.0, 'Regular', Font size=16 weight=normal slant=roman style=None), 
 (141.0, 64.0, 'Small', Font size=12 weight=normal slant=roman style=None)]

>>> display_list = test_layout("Start<br>Regular<br>Regular <small><small>Small")
>>> baseline(display_list[1]) - baseline(display_list[0])
20.0
>>> baseline(display_list[3]) - baseline(display_list[1])
20.0

Testing Browser

Now let's test integration of layout into the Browser class.

>>> url = 'http://wbemocks.test/chapter3-example1'
>>> wbemocks.socket.respond_200(url=url, 
...   body="<small>abc<i>def</i></small>")
>>> this_browser = browser.Browser()
>>> this_browser.load(browser.URL(url))

Testing the display list output of this URL:

>>> wbemocks.normalize_display_list(this_browser.display_list)  #doctest: +NORMALIZE_WHITESPACE 
[(13.0, 20.625, 'abc', Font size=14 weight=normal slant=roman style=None), 
 (69.0, 20.625, 'def', Font size=14 weight=normal slant=italic style=None)]

And the canvas:

>>> wbemocks.patch_canvas()
>>> this_browser = browser.Browser()
>>> this_browser.load(browser.URL(url))
create_text: x=13 y=20.625 text=abc font=Font size=14 weight=normal slant=roman style=None anchor=nw
create_text: x=69 y=20.625 text=def font=Font size=14 weight=normal slant=italic style=None anchor=nw
>>> wbemocks.unpatch_canvas()