pytest-expectdir 1.0

A pytest plugin to provide initial/expected directories, and check a test transforms the initial directory to the expected one

pytest-expectdir

This pytest plugin provides an easy way to test file generation and file-system transformation.

Install

pip install pytest-expectdir

Usage

Here is the workflow :

Create a directory containing files and directories expected to be generated, and optionally one with your initial data so that it looks like this :

my_pkg/
  my_pkg/
    ...
  tests/
    test_feature.py
    data_test_feature/
      initial/
        ... (optional) your initial data
      expected/
        ... expected output tree

Then you write your test as follow :

test_feature.py

def test_feature(expectdir):
  with expectdir('data_test_feature') as output_dir:
    # Do whatever you want inside output_dir, which is a temporary directory copied from initial/
  # At the end of the with, output_dir gets compared with expected
  # ...And you get a fancy report of the difference if there are (as an AssertionError).

Note that you can also pass manually the keyword arguments initial and expected to expectdir. If, for example, you have multiple tests ending up with the same expected result, or with the same initial one.

The following is equivalent to the previous example :

def test_feature(expectdir):
  with expectdir(initial='data_test_feature/initial', expected='data_test_feature/expected') as output_dir:
    # ...

How Fancy ?

Here is a sample from the tests :

In [1]: import sys
   ...: from pytest_expectdir.plugin import cmpdir, formatDiff
   ...: initial = './tests/data/test3/initial/'
   ...: expected = './tests/data/test3/expected/'
   ...: formatDiff(sys.stdout, initial, expected, cmpdir(initial, expected)[1])
Directories ./tests/data/test3/expected/ (expected) is different from ./tests/data/test3/initial/ (candidate).
Missing in candidate :
dir3/
f1
Extra in candidate :
dir2/
f4
In both directories but different content:

f3:
  - This line is removed
  - And this one too
    This is a complex test
  - Hello 3
  + Hello 3 And replaced ones
    With some lines
  + And added lines
    And otherlines
    common 1
    common 2
  [...] --- expected:11 / candidate:10 ---
    common 6
    common 7
    common 8
  - and diff 1
  + diff

dir4/f3:
  - This line is removed
  - And this one too
    This is a complex test
  - Hello 3
  + Hello 3 And replaced ones
    With some lines
  + And added lines
    And otherlines
    common 1
    common 2
  [...] --- expected:11 / candidate:10 ---
    common 6
    common 7
    common 8
  - and diff 1
  + diff