Test case that compares pip freeze output to the project's requirements.txt file

test_pip_requirements.py

import unittest
import subprocess
from StringIO import StringIO


class ProjectRequirementsSpec(unittest.TestCase):

    def parse_requirement(self, requirement):
        requirement = requirement.replace('\n', '')

        if requirement.startswith('#') or requirement == '':
            return False, False

        if '==' in requirement:
            parts = requirement.split('==')
            if isinstance(parts, list) and len(parts) == 2:
                name = parts[0]
                version = parts[1]

                if name in ['distribute', 'setuptools']:
                    return name, False

                return name, version
        elif requirement.startswith('git+git://'):

            parts = requirement.split('/')
            last = len(parts) - 1
            parts = parts[last].split('.git@')
            name = parts[0]
            version = parts[1].replace('release-', '')

            if parts[1].startswith('release-'):
                return name, version

            return name, False
        else:
            return requirement, False

        return False, False

    def test_pip_requirements(self):

        p = subprocess.Popen(
            ["pip", "freeze"],
            stdout=subprocess.PIPE)

        out, err = p.communicate()
        actual_requirements = StringIO(out)
        requirement = 'requirement'
        actual = {}

        while requirement:
            requirement = actual_requirements.readline()

            name, version = self.parse_requirement(requirement.replace('\n', ''))

            if name and version:
                actual[name] = version

        expected_requirements = open('requirements.txt')
        expected_requirements = StringIO(expected_requirements.read())
        requirement = 'requirement'

        while requirement:
            requirement = expected_requirements.readline()

            name, version = self.parse_requirement(requirement.replace('\n', ''))

            if not name or not isinstance(name, str) or name.startswith(u"#"):
                continue

            # pip freeze does not detect any of these packages
            if name in [u"distribute", u"setuptools", u"pip"]:
                continue

            if name:
                actual_version = actual.get(name)
                assert actual_version is not None, u"Expected %s to be installed" % name

                if version:
                    assert actual_version == version, u"%s %s does not match expected %s %s" % (name, version, name, actual_version)
                    print("found %s %s" % (name, version))
                else:
                    print("found %s" % name)
            else:
                raise AssertionError(u"Failed to parse expected requirements file, is it formatted correctly?")