gistfile1.py

from webassets.test import TempEnvironmentHelper
from webassets import *


with TempEnvironmentHelper() as h:
    h.create_files({
        'empty': '',
        'scss/styles1.scss': 'h1 { color: red }',
        'scss/styles2.scss': 'h2 { color: green }',
    })
    
    h.env.debug = True

    scss_bundle = Bundle('scss/styles1.scss',
        'scss/styles2.scss',
        filters='pyscss', debug=False,
        output='gen/scss/styles.css')
        
    css_compressed_bundle = Bundle(scss_bundle,
        filters='yui_css,datauri',
        output='gen/css/compressed_bundle.css')
        
    css_compressed_bundle.urls(env=h.env)

    assert not h.exists('gen/css/compressed_bundle.css')
    h.p('gen/scss/styles.css')