Mock the actual setup provider defined in setup.py

Currently `setup` is always mocked using `distutils.core`
but this might cause issues with certain packages.
Fix this behavior by parsing the `setup.py` file for the correct
module to import.

Closes: #116

Signed-off-by: Bennati, Stefano <stefano.bennati@here.com>

Author: bennati

src/python_inspector/setup_py_live_eval.py

@@ -19,7 +19,6 @@
     import ConfigParser as configparser
 
 import mock
-import setuptools
 from commoncode.command import pushd
 from packvers.requirements import Requirement
 
@@ -54,11 +53,24 @@ def iter_requirements(level, extras, setup_file):
     setup_requires = {}
     # change directory to setup.py path
     with pushd(os.path.dirname(setup_file)):
-        with mock.patch.object(setuptools, "setup") as mock_setup:
-            sys.path.append(os.path.dirname(setup_file))
-            g = {"__file__": setup_file, "__name__": "__main__"}
-            with open(setup_file) as sf:
-                exec(sf.read(), g)
+        with open(setup_file) as sf:
+            file_contents = sf.read()
+            setup_provider = re.findall(r"from ([a-z._]+) import setup", file_contents)
+            if len(setup_provider) == 1:
+                setup_provider = setup_provider[0]
+            else:
+                setup_provider = ""
+            if not ((setup_provider == "distutils.core") or (setup_provider == "setuptools")):
+                print(
+                    f"Warning: unable to recognize 'import {setup_provider}' in {setup_file}: "
+                    "defaulting to 'distutils.core'."
+                )
+                setup_provider = "distutils.core"
+            exec(f"import {setup_provider}")
+            with mock.patch.object(eval(setup_provider), "setup") as mock_setup:
+                sys.path.append(os.path.dirname(setup_file))
+                g = {"__file__": setup_file, "__name__": "__main__"}
+                exec(file_contents, g)
             sys.path.pop()
             # removing the assertion `assert g["setup"]`` since this is not true for all cases
             # for example when setuptools.setup() is called instead of setup()

tests/data/setup-distutils.txt

@@ -0,0 +1,40 @@
+"""
+Copyright 2018 Matthew Aynalem
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+from distutils.core import setup
+from setuptools import find_packages
+
+setup(
+    name='packer.py',
+    version='0.3.0',
+    author='Matthew Aynalem',
+    author_email='maynalem@gmail.com',
+    packages=['packerpy'],
+    url='https://github.com/mayn/packer.py',
+    license='Apache License 2.0',
+    description='packer.py - python library to run hashicorp packer CLI commands',
+    keywords="hashicorp packer",
+    install_requires=[
+    ],
+    classifiers=[
+        'License :: OSI Approved :: Apache Software License',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+    ],
+)

tests/test_setup_py_live_eval.py

@@ -17,6 +17,7 @@
 
 REQ = abspath(join(dirname(__file__), "./data/requirements.devel.txt"))
 SETUP = abspath(join(dirname(__file__), "./data/setup.txt"))
+SETUP_DISTUTILS = abspath(join(dirname(__file__), "./data/setup-distutils.txt"))
 
 
 def test_iter_requirements_with_setup_py():
@@ -29,3 +30,15 @@ def test_iter_requirements_with_setup_py():
 
     # Dev
     assert list(iter_requirements("dev", [], SETUP)) == ["click>=6.1.0", "mock>=1.3.0"]
+
+
+def test_iter_requirements_with_setup_py_distutils():
+    """Test against setup.py files which import distutils"""
+    # Min
+    assert list(iter_requirements("min", [], SETUP_DISTUTILS)) == []
+
+    # PyPI
+    assert list(iter_requirements("pypi", [], SETUP_DISTUTILS)) == []
+
+    # Dev
+    assert list(iter_requirements("dev", [], SETUP_DISTUTILS)) == []