Dynamic assertions

Dynamic has_<name>() assertions, generated on demand for any attribute, property, zero-arg method, or dict key on the value under test.

Dynamic assertions mixin.

When testing attributes of an object (or the contents of a dict), the is_equal_to() assertion can be a bit verbose:

fred = Person('Fred', 'Smith')

assert_that(fred.first_name).is_equal_to('Fred')
assert_that(fred.name).is_equal_to('Fred Smith')
assert_that(fred.say_hello()).is_equal_to('Hello, Fred!')

Instead, use dynamic assertions in the form of has_<name>() where <name> is the name of any attribute, property, or zero-argument method on the given object. Dynamic equality assertions test if actual is equal to expected using the == operator. Using dynamic assertions, we can rewrite the above example as:

assert_that(fred).has_first_name('Fred')
assert_that(fred).has_name('Fred Smith')
assert_that(fred).has_say_hello('Hello, Fred!')

Similarly, dynamic assertions also work on any dict-like object:

fred = {
    'first_name': 'Fred',
    'last_name': 'Smith',
    'shoe_size': 12
}

assert_that(fred).has_first_name('Fred')
assert_that(fred).has_last_name('Smith')
assert_that(fred).has_shoe_size(12)