[3.6] Improves the ability to build in CI (GH-5730)

2 files changed, 13 insertions, 7 deletions

diff --git a/Lib/test/support/script_helper.py b/Lib/test/support/script_helper.py
index ca5f9c20..507dc48 100644
--- a/Lib/test/support/script_helper.py
+++ b/Lib/test/support/script_helper.py
@@ -39,6 +39,11 @@ def interpreter_requires_environment():
     """
     global __cached_interp_requires_environment
     if __cached_interp_requires_environment is None:
+        # If PYTHONHOME is set, assume that we need it
+        if 'PYTHONHOME' in os.environ:
+            __cached_interp_requires_environment = True
+            return True
+
         # Try running an interpreter with -E to see if it works or not.
         try:
             subprocess.check_call([sys.executable, '-E',
@@ -165,7 +170,9 @@ def spawn_python(*args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kw):
     kw is extra keyword args to pass to subprocess.Popen. Returns a Popen
     object.
     """
-    cmd_line = [sys.executable, '-E']
+    cmd_line = [sys.executable]
+    if not interpreter_requires_environment():
+        cmd_line.append('-E')
     cmd_line.extend(args)
     # Under Fedora (?), GNU readline can output junk on stderr when initialized,
     # depending on the TERM setting.  Setting TERM=vt100 is supposed to disable
diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index 98441b0..32d2df9 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -10,7 +10,7 @@ import subprocess
 import tempfile
 from test.support import script_helper, is_android
 from test.support.script_helper import (spawn_python, kill_python, assert_python_ok,
-    assert_python_failure)
+    assert_python_failure, interpreter_requires_environment)
 
 
 # XXX (ncoghlan): Move to script_helper and make consistent with run_python
@@ -57,6 +57,8 @@ class CmdLineTest(unittest.TestCase):
         rc, out, err = assert_python_ok('-vv')
         self.assertNotIn(b'stack overflow', err)
 
+    @unittest.skipIf(interpreter_requires_environment(),
+                     'Cannot run -E tests when PYTHON env vars are required.')
     def test_xoptions(self):
         def get_xoptions(*args):
             # use subprocess module directly because test.support.script_helper adds
@@ -272,11 +274,7 @@ class CmdLineTest(unittest.TestCase):
 
     def test_displayhook_unencodable(self):
         for encoding in ('ascii', 'latin-1', 'utf-8'):
-            # We are testing a PYTHON environment variable here, so we can't
-            # use -E, -I, or script_helper (which uses them).  So instead we do
-            # poor-man's isolation by deleting the PYTHON vars from env.
-            env = {key:value for (key,value) in os.environ.copy().items()
-                   if not key.startswith('PYTHON')}
+            env = os.environ.copy()
             env['PYTHONIOENCODING'] = encoding
             p = subprocess.Popen(
                 [sys.executable, '-i'],
@@ -491,6 +489,7 @@ class CmdLineTest(unittest.TestCase):
                                           cwd=tmpdir)
             self.assertEqual(out.strip(), b"ok")
 
+
 def test_main():
     test.support.run_unittest(CmdLineTest)
     test.support.reap_children()