>>> import albatross
>>> ctx = albatross.SimpleContext('.')
>>> ctx.locals.src = 'http://icons.r.us/spam.png'
>>> albatross.Template(ctx, '<magic>', '''
... <al-img expr="src" whitespace>
... ''').to_html(ctx)
>>> ctx.flush_content()
<img src="http://icons.r.us/spam.png" />
