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Options and configuration

Flake8 can be invoked with -- options and can read values from project configuration files.

All names of Flake8-AAA's options and configuration values are prefixed with "aaa". E.g. --aaa-act-block-style.

Act block style

Command line flag
--aaa-act-block-style
Configuration option
aaa_act_block_style

The Act block style option adjusts how Flake8-AAA builds the Act block from the Act node.

The allowed values are "default" and "large".

Default

In default mode the Act block is the single Act node, best demonstrated by example:

result = do_thing()

Or...

with pytest.raises(ValueError):
    do_thing()

The important feature of default Act blocks is that they do not contain any context managers other than pytest or unittest ones.

def test_with():
    a_class = AClass()
    with freeze_time("2021-02-02 12:00:02"):

        result = a_class.action('test')

    assert result == 'test'

In the example above, Flake8-AAA considers the with freeze_time() context manager to be in the Arrange block. It therefore expects a blank line between it and the result = Act block.

Large

Large style Act blocks have been provided to be compatible with Black.

In Large mode the Act block can grow to include context managers that wrap it. For example, referring to the test above, this would be formatted as follows with Large Act blocks:

def test_with():
    a_class = AClass()

    with freeze_time("2021-02-02 12:00:02"):
        result = a_class.action('test')

    assert result == 'test'

The result = result assignment Act block expands to include the freeze_time() context manager. In this way, the blank line that divides the Arrange block from the Act block can be before the context manager - a format which is compatible with Black.

Note however, the context manager only joined the Act block because the Act node was the first line in the context manager's body. If we moved the AClass() initialisation inside the context manager, something different would happen:

def test_with():
    with freeze_time("2021-02-02 12:00:02"):
        a_class = AClass()

        result = a_class.action('test')

    assert result == 'test'

This time the result assignment does not consume the context manager. Instead, the freeze_time() context manager and the a_class initialisation make up the Arrange block, and there's a single blank line between that and the simple result assignment Act block.