tf.test.StubOutForTesting

Support class for stubbing methods out for unit testing.

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

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Undoes all SmartSet() & Set() calls, restoring original definitions.

Set

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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

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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

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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

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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__

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__exit__

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© 2020 The TensorFlow Authors. All rights reserved.
Licensed under the Creative Commons Attribution License 3.0.
Code samples licensed under the Apache 2.0 License.
https://www.tensorflow.org/versions/r1.15/api_docs/python/tf/test/StubOutForTesting