def test_method_called_with_args(self):
# You can check that the correct arguments are passed to the method call. That said, for this example to work,
# you still need to define what the mocked function should return: an `EnvironmentError` is raised.
Expect("SomeAPI").to_receive("do_something_else").with_args(x=12)
assert_raises(EnvironmentError, SomeAPI.do_something_else, x=12)
# Note that in case the arguments passed do not match expectations, an `ExpectationError` is raised.
Expect("SomeAPI").to_receive("do_something_else").with_args(x=12)
assert_raises(ExpectationError, SomeAPI.do_something_else, x=13)
def test_method_called_twice(self):
# With the same setup as above, calling the same method a second time will raise an error. 2 `Expect`
# statements are required for that.
with Expectations():
Expect("SomeAPI").to_receive("get_something").with_args("foo", "bar").and_return(False)
SomeAPI.get_something("foo", "bar")
assert_raises(ExpectationError, SomeAPI.get_something, "foo", "bar")
def test_method_raise(self):
# Expecting the function `get_something` to be called, with specifc arguments passed to it, and overriding its
# behavior to raise the desired error. This test case checks that the method is called, with the right input,
# and modifies its behavior. Can be useful to ensure that your code handles exceptions gracefully.
Expect("SomeAPI").to_receive("get_something").with_args("foo", "bar").and_raise(ValueError("My error"))
# Again, silly example, just to illustrate what can be done with the framework.
assert_raises(ValueError, SomeAPI.get_something, "foo", "bar")
def test_method_return(self):
# Expecting the function `get_something` to be called, with specifc arguments passed to it, and overriding its
# behavior to return a desired output. This test case checks that the method is called, with the right input,
# and modifies its return value(s). Can be useful in case the `get_something` performs a call to an external
# service that you want to avoid in test environment, and therefore want to mock the response with your output.
Expect("SomeAPI").to_receive("get_something").with_args("foo", "bar").and_return(False)
# This example is silly of course. Instead, some more complex logic in your module would trigger the call
# to `get_something` with the specific input you expect. Here, we mock the output with a `return False`.
assert not SomeAPI.get_something("foo", "bar")
def test_instance_method(self):
# Everything works with instance methods
with Expectations():
Expect("SomeAPI").to_receive("update_attribute").and_return("sshhhh")
assert SomeAPI().update_attribute("secret_value") == "sshhhh"
def test_static_method(self):
# Everything works with staticmethods defined
with Expectations():
Expect("SomeAPI").to_receive("compute_sum").with_args(1, 2).and_return(4)
assert SomeAPI.compute_sum(1, 2) == 4
def test_method_raise_only(self):
# Similar example as above, with no check of arguments passed to `get_something`.
with Expectations():
Expect("SomeAPI").to_receive("get_something").and_raise(ValueError("My error"))
assert_raises(ValueError, SomeAPI.get_something, "python", "snake")
def test_method_return_only(self):
# Similar example as above, with no check of arguments passed to `get_something`.
with Expectations():
Expect("SomeAPI").to_receive("get_something").and_return(42)
assert SomeAPI.get_something("foo", "bar") == 42
def test_method_called(self):
# The `get_something` method is mocked, an `Expect` statement is used, but it does not describe what the method
# should perform. Therefore an exception is raised.
with Expectations():
Expect("SomeAPI").to_receive("do_something_else")
assert_raises(EnvironmentError, SomeAPI.do_something_else, x=1)
def tearDown(self):
Expect.tear_down()