corrected as per notations from @YannickJadoul on #113

cibuildwheel/__main__.py

@@ -105,6 +105,26 @@ def main():
     # This needs to be passed on to the docker container in linux.py
     os.environ['CIBUILDWHEEL'] = '1'
 
+    try:
+        project_setup_py = os.path.join(project_dir, 'setup.py')
+        name_output = subprocess.check_output([sys.executable, project_setup_py, '--name'],
+                                              universal_newlines=True)
+        # the last line of output is the name
+        package_name = name_output.strip().splitlines()[-1]
+    except subprocess.CalledProcessError as err:
+        if not os.path.exists(project_setup_py):
+            print('cibuildwheel: Could not find setup.py at root of project', file=sys.stderr)
+            exit(2)
+        else:
+            print(err.output)
+            print('cibuildwheel: Failed to get name of the package. Command was %s' % err.cmd,
+                  file=sys.stderr)
+            exit(err.returncode)
+     if package_name == '' or package_name == 'UNKNOWN':
+        print('cibuildwheel: Invalid package name "%s". Check your setup.py' % package_name,
+              file=sys.stderr)
+        exit(2)
+
     build_options = dict(
         project_dir=project_dir,
         output_dir=output_dir,

cibuildwheel/linux.py

@@ -135,6 +135,7 @@ def build(project_dir, output_dir, test_command, test_requires, before_build, bu
         try:
             run_docker(['create',
                         '--env', 'CIBUILDWHEEL',
+                        '--name', container_name,
                         '-i',
                         '-v', '/:/host', # ignored on Circle
                         docker_image, '/bin/bash'])

test/03_before_build/setup.py

@@ -1,6 +1,23 @@
 from setuptools import setup, Extension
 import sys, os
 
+# assert that the Python version as written to pythonversion.txt in the CIBW_BEFORE_BUILD step
+# is the same one as is currently running.
+version_file = 'c:\\pythonversion.txt' if sys.platform == 'win32' else '/tmp/pythonversion.txt'
+with open(version_file) as f:
+    stored_version = f.read()
+print('stored_version', stored_version)
+print('sys.version', sys.version)
+assert stored_version == sys.version
+# check that the executable also was written
+executable_file = 'c:\\pythonexecutable.txt' if sys.platform == 'win32' else '/tmp/pythonexecutable.txt'
+with open(executable_file) as f:
+    stored_executable = f.read()
+print('stored_executable', stored_executable)
+print('sys.executable', sys.executable)
+# windows/mac are case insensitive
+assert os.path.realpath(stored_executable).lower() == os.path.realpath(sys.executable).lower()
+
 setup(
     name="spam",
     ext_modules=[Extension('spam', sources=['spam.c'])],

test/04_build_skip/setup.py

@@ -1,6 +1,12 @@
 from setuptools import setup, Extension
 import sys
 
+# explode if run on Python 2.7 or Python 3.4 (these should be skipped)
+if sys.version_info[0:2] == (2, 7):
+    raise Exception('Python 2.7 should not be built')
+if sys.version_info[0:2] == (3, 4):
+    raise Exception('Python 3.4 should be skipped')
+
 setup(
     name="spam",
     ext_modules=[Extension('spam', sources=['spam.c'])],

test/05_environment/setup.py

@@ -1,6 +1,19 @@
 from setuptools import setup, Extension
 import sys, os
 
+# explode if environment isn't correct, as set in CIBW_ENVIRONMENT
+CIBW_TEST_VAR = os.environ.get('CIBW_TEST_VAR')
+CIBW_TEST_VAR_2 = os.environ.get('CIBW_TEST_VAR_2')
+PATH = os.environ.get('PATH')
+if CIBW_TEST_VAR != 'a b c':
+    raise Exception('CIBW_TEST_VAR should equal "a b c". It was "%s"' % CIBW_TEST_VAR)
+if CIBW_TEST_VAR_2 != '1':
+    raise Exception('CIBW_TEST_VAR_2 should equal "1". It was "%s"' % CIBW_TEST_VAR_2)
+if '/opt/cibw_test_path' not in PATH:
+    raise Exception('PATH should contain "/opt/cibw_test_path". It was "%s"' % PATH)
+if '$PATH' in PATH:
+    raise Exception('$PATH should be expanded in PATH. It was "%s"' % PATH)
+
 setup(
     name="spam",
     ext_modules=[Extension('spam', sources=['spam.c'])],

test/06_docker_images/setup.py

@@ -2,6 +2,11 @@ import os, sys
 
 from setuptools import setup, Extension
 
+# check that we're running in the correct docker image as specified in the
+# environment options CIBW_MANYLINUX1_*_IMAGE
+if 'linux' in sys.platform and not os.path.exists('/dockcross'):
+    raise Exception('/dockcross directory not found. Is this test running in the correct docker image?')
+
 setup(
     name="spam",
     ext_modules=[Extension('spam', sources=['spam.c'])],