Add assert_true(), assert_false()

[wting]

Adds assert_true() and assert_false() shortcut wrappers.

[milki]

I saw a suggestion:

assert_that(blah.bla, is_true())

This would allow the user to supply their own truth.

[wting]

@att14: Truthy.

A user can always be explicit with assert_true(x is True).

[att14]

This is incorrect then.

In [1]: 1 == True
Out[1]: True

In [2]: 'hi' == True
Out[2]: False

In [3]: bool('hi')
Out[3]: True

In [4]: 2 == True
Out[4]: False

In [5]: import testify as T

In [6]: T.assert_equal(2, True)
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
<ipython-input-6-a96114e6ec5b> in <module>()
----> 1 T.assert_equal(2, True)

/Library/Python/2.7/site-packages/testify-0.3.8-py2.7.egg/testify/assertions.pyc in assert_equal(lval, rval, message)
    239         assert lval == rval, \
    240             "assertion failed: l == r\nl: %r\nr: %r\n\n%s" % \
--> 241                 (lval, rval, _diff_message(lval, rval))
    242
    243 assert_equals = assert_equal

AssertionError: assertion failed: l == r
l: 2
r: True

Diff:
l: 2
r: True

In [7]: T.assert_equal(1, True)

[att14]

Also, I doubt this will be accepted without tests.

[wting]

Updated. FYI this mimics unittest.assertTrue() and unittest.assertFalse() behavior.

[mrtyler]

ShipIt

Can't automatically merge though so I'm not merging it right now.

[wting]

Rebased on Yelp/Testify/master, only test failures are catbox related.

[mrtyler]

There are still (or again) conflicts. :/. I think you're thumb-wrestling with @bukzor, whose changes are more urgent so they get priority.

[wting]

Rebased off Yelp/Testify/master again.

Whitespace changes are according to Yelp guidelines (2 lines between top level elements, 1 blank line after class definition) for consistency's sake.

[wting]

1. The original implementation was just a wrapper around assert_equal(), but the wrong message is printed when the assertion fails.
2. It's a convenience function. It adds value by reducing boilerplate and make it a bit more explicit what you're testing. This seems to be a general consensus since most popular testing frameworks have an equivalent function.