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|
Support class for stubbing methods out for unit testing.
tf.test.StubOutForTesting()
Sample Usage:
You want os.path.exists() to always return true during testing.
stubs = StubOutForTesting() stubs.Set(os.path, 'exists', lambda x: 1) ... stubs.CleanUp()
The above changes os.path.exists into a lambda that returns 1. Once the ... part of the code finishes, the CleanUp() looks up the old value of os.path.exists and restores it.
Methods
CleanUp
CleanUp()
Undoes all SmartSet() & Set() calls, restoring original definitions.
Set
Set(
parent, child_name, new_child
)
In parent, replace child_name's old definition with new_child.
The parent could be a module when the child is a function at module scope. Or the parent could be a class when a class' method is being replaced. The named child is set to new_child, while the prior definition is saved away for later, when UnsetAll() is called.
This method supports the case where child_name is a staticmethod or a classmethod of parent.
| Args | |
|---|---|
parent
|
The context in which the attribute child_name is to be changed. |
child_name
|
The name of the attribute to change. |
new_child
|
The new value of the attribute. |
SmartSet
SmartSet(
obj, attr_name, new_attr
)
Replace obj.attr_name with new_attr.
This method is smart and works at the module, class, and instance level while preserving proper inheritance. It will not stub out C types however unless that has been explicitly allowed by the type.
This method supports the case where attr_name is a staticmethod or a classmethod of obj.
Notes:
- If obj is an instance, then it is its class that will actually be stubbed. Note that the method Set() does not do that: if obj is an instance, it (and not its class) will be stubbed.
- The stubbing is using the builtin getattr and setattr. So, the get and set will be called when stubbing ( probably be to manipulate obj.dict instead of getattr() and setattr()).
| Args | |
|---|---|
obj
|
The object whose attributes we want to modify. |
attr_name
|
The name of the attribute to modify. |
new_attr
|
The new value for the attribute. |
| Raises | |
|---|---|
AttributeError
|
If the attribute cannot be found. |
SmartUnsetAll
SmartUnsetAll()
Reverses SmartSet() calls, restoring things to original definitions.
This method is automatically called when the StubOutForTesting() object is deleted; there is no need to call it explicitly.
It is okay to call SmartUnsetAll() repeatedly, as later calls have no effect if no SmartSet() calls have been made.
UnsetAll
UnsetAll()
Reverses Set() calls, restoring things to their original definitions.
This method is automatically called when the StubOutForTesting() object is deleted; there is no need to call it explicitly.
It is okay to call UnsetAll() repeatedly, as later calls have no effect if no Set() calls have been made.
__enter__
__enter__()
__exit__
__exit__(
unused_exc_type, unused_exc_value, unused_tb
)