fudge.inspector

Value inspectors that can be passed to fudge.Fake.with_args() for more expressive argument matching.

As a mnemonic device, an instance of the fudge.inspector.ValueInspector is available as “arg” :

>>> import fudge
>>> from fudge.inspector import arg
>>> image = fudge.Fake("image").expects("save").with_args(arg.endswith(".jpg"))

In other words, this declares that the first argument to image.save() should end with the suffix “.jpg”

class fudge.inspector.ValueInspector

Dispatches tests to inspect values.

any_value()

Match any value.

This is pretty much just a placeholder for when you want to inspect multiple arguments but don’t care about all of them.

>>> import fudge
>>> from fudge.inspector import arg
>>> db = fudge.Fake("db")
>>> db = db.expects("transaction").with_args(
...             "insert", isolation_level=arg.any_value())
... 
>>> db.transaction("insert", isolation_level="lock")
>>> fudge.verify()

This also passes:

>>> db.transaction("insert", isolation_level="autocommit")
>>> fudge.verify()

contains(part)

Ensure that a value contains some part.

This is useful for when you only care that a substring or subelement exists in a value.

>>> import fudge
>>> from fudge.inspector import arg
>>> addressbook = fudge.Fake().expects("import_").with_args(
...                                     arg.contains("Baba Brooks"))
... 
>>> addressbook.import_("Bill Brooks; Baba Brooks; Henry Brooks;")
>>> fudge.verify()

Since contains() just invokes the __in__() method, checking that a list item is present works as expected :

>>> colorpicker = fudge.Fake("colorpicker")
>>> colorpicker = colorpicker.expects("select").with_args(arg.contains("red"))
>>> colorpicker.select(["green","red","blue"])
>>> fudge.verify()

endswith(part)

Ensure that a value ends with some part.

This is useful for when values with dynamic parts that are hard to replicate.

>>> import fudge
>>> from fudge.inspector import arg
>>> tmpfile = fudge.Fake("tempfile").expects("mkname").with_args(
...                                             arg.endswith(".tmp"))
... 
>>> tmpfile.mkname("7AakkkLazUUKHKJgh908JKjlkh.tmp")
>>> fudge.verify()

has_attr(**attributes)

Ensure that an object value has at least these attributes.

This is useful for testing that an object has specific attributes.

>>> import fudge
>>> from fudge.inspector import arg
>>> db = fudge.Fake("db").expects("update").with_args(arg.has_attr(
...                                                       first_name="Bob",
...                                                       last_name="James" ))
... 
>>> class User:
...     first_name = "Bob"
...     last_name = "James"
...     job = "jazz musician" # this is ignored
... 
>>> db.update(User())
>>> fudge.verify()

In case of error, the other object’s __repr__ will be invoked:

>>> class User:
...     first_name = "Bob"
... 
...     def __repr__(self):
...         return repr(dict(first_name=self.first_name))
... 
>>> db.update(User())
...
AssertionError: fake:db.update(arg.has_attr(first_name='Bob', last_name='James')) was called unexpectedly with args ({'first_name': 'Bob'})

passes_test(test)

Check that a value passes some test.

For custom assertions you may need to create your own callable to inspect and verify a value.

>>> def is_valid(s):
...     if s in ('active','deleted'):
...         return True
...     else:
...         return False
... 
>>> import fudge
>>> from fudge.inspector import arg
>>> system = fudge.Fake("system")
>>> system = system.expects("set_status").with_args(arg.passes_test(is_valid))
>>> system.set_status("active")
>>> fudge.verify()

The callable you pass takes one argument, the value, and should return True if it’s an acceptable value or False if not.

>>> system.set_status("sleep") 
...
AssertionError: fake:system.set_status(arg.passes_test(<function is_valid at ...>)) was called unexpectedly with args ('sleep')

If it makes more sense to perform assertions in your test function then be sure to return True :

>>> def is_valid(s):
...     assert s in ('active','deleted'), (
...         "Unexpected status value: %s" % s)
...     return True
... 
>>> import fudge
>>> from fudge.inspector import arg
>>> system = fudge.Fake("system")
>>> system = system.expects("set_status").with_args(arg.passes_test(is_valid))
>>> system.set_status("sleep")
...
AssertionError: Unexpected status value: sleep

startswith(part)

Ensure that a value starts with some part.

This is useful for when values with dynamic parts that are hard to replicate.

>>> import fudge
>>> from fudge.inspector import arg
>>> keychain = fudge.Fake("keychain").expects("accept_key").with_args(
...                                                     arg.startswith("_key"))
... 
>>> keychain.accept_key("_key-18657yojgaodfty98618652olkj[oollk]")
>>> fudge.verify()