Cannot install pytest from requirements.txt

Question

I am using pip3 to install modules for my python project. My requirements.txt looks like this:

urllib3==1.22
cx_freeze==6.0b1
pytest==3.2.2
pytest-cov==2.5.1
pytest-dependency==0.2

I clearly have pytest added to my requirements but when I run pip3 install -r requirements.txt it cannot find pytest and shows the following exception:

Complete output from command python setup.py egg_info:
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/tmp/pip-build-y300zryw/pytest-dependency/setup.py", line 9, in <module>
    import pytest_dependency
  File "/tmp/pip-build-y300zryw/pytest-dependency/pytest_dependency.py", line 8, in <module>
    import pytest
ModuleNotFoundError: No module named 'pytest'

When I manually do a pip3 install pytest and then run my requirements file, it works fine.

Why does pytest not install from requirements.txt ?

Answer 1

for your version of pytest-cov need pytest==3.4.2 so simple edit the requirements.txt to

urllib3==1.22
cx_freeze==6.0b1
pytest==3.4.2
pytest-cov==2.5.1
pytest-dependency==0.2

first time it help me, but now it work even for 3.2.2

$ workon ptest

(ptest) $ python -V
Python 3.5.3

look on installed

(ptest) $ pip freeze
attrs==17.4.0
coverage==4.5.1
pluggy==0.6.0
py==1.5.2
six==1.11.0

install

(ptest) $ cat requirements.txt 
urllib3==1.22
cx_freeze==6.0b1
pytest==3.2.2
pytest-cov==2.5.1
pytest-dependency==0.2

(ptest) $ pip install -r requirements.txt 
Collecting urllib3==1.22 (from -r requirements.txt (line 1))
  Using cached urllib3-1.22-py2.py3-none-any.whl
Collecting cx_freeze==6.0b1 (from -r requirements.txt (line 2))
Collecting pytest==3.2.2 (from -r requirements.txt (line 3))
  Using cached pytest-3.2.2-py2.py3-none-any.whl
Collecting pytest-cov==2.5.1 (from -r requirements.txt (line 4))
  Using cached pytest_cov-2.5.1-py2.py3-none-any.whl
Collecting pytest-dependency==0.2 (from -r requirements.txt (line 5))
Requirement already satisfied: setuptools in /home/user/.virtualenvs/ptest/lib/python3.5/site-packages (from pytest==3.2.2->-r requirements.txt (line 3))
Requirement already satisfied: py>=1.4.33 in /home/user/.virtualenvs/ptest/lib/python3.5/site-packages (from pytest==3.2.2->-r requirements.txt (line 3))
Requirement already satisfied: coverage>=3.7.1 in /home/user/.virtualenvs/ptest/lib/python3.5/site-packages (from pytest-cov==2.5.1->-r requirements.txt (line 4))
Installing collected packages: urllib3, cx-freeze, pytest, pytest-cov, pytest-dependency
Successfully installed cx-freeze-6.0b1 pytest-3.2.2 pytest-cov-2.5.1 pytest-dependency-0.2 urllib3-1.22

check it

(ptest) $ pip freeze
attrs==17.4.0
coverage==4.5.1
cx-Freeze==6.0b1
pluggy==0.6.0
py==1.5.2
pytest==3.2.2
pytest-cov==2.5.1
pytest-dependency==0.2
six==1.11.0
urllib3==1.2

Answer 2

The problem lies in the version of pytest-dependency you have - 0.2 is way too old. You can't install pytest-dependency==0.2 in one pass with pytest :

$ pip install pytest-dependency==0.2 pytest

will fail.

However, this issue was fixed in 0.3 version, see issue #13 and issue #14 closed. So just bump pytest-dependency to the current version and you're good to go:

urllib3==1.22
cx_freeze==6.0b1
pytest==3.2.2
pytest-cov==2.5.1