Merge pull request #3301 from juliantaylor/no-python-test

allow python3 tests without python installed

IPython/utils/_process_common.py

@@ -103,9 +103,7 def process_handler(cmd, callback, stderr=subprocess.PIPE):
 
 
 def getoutput(cmd):
-    """Return standard output of executing cmd in a shell.
-
-    Accepts the same arguments as os.system().
+    """Run a command and return its stdout/stderr as a string.
 
     Parameters
     ----------
@@ -114,9 +112,12 def getoutput(cmd):
 
     Returns
     -------
-    stdout : str
+    output : str
+      A string containing the combination of stdout and stderr from the
+    subprocess, in whatever order the subprocess originally wrote to its
+    file descriptors (so the order of the information in this string is the
+    correct order as would be seen if running the command in a terminal).
     """
-
     out = process_handler(cmd, lambda p: p.communicate()[0], subprocess.STDOUT)
     if out is None:
         return ''

IPython/utils/tests/test_process.py

@@ -15,6 +15,7 Tests for platutils.py
 #-----------------------------------------------------------------------------
 
 import sys
+import os
 from unittest import TestCase
 
 import nose.tools as nt
@@ -24,13 +25,15 from IPython.utils.process import (find_cmd, FindCmdError, arg_split,
 from IPython.testing import decorators as dec
 from IPython.testing import tools as tt
 
+python = os.path.basename(sys.executable)
+
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 def test_find_cmd_python():
     """Make sure we find sys.exectable for python."""
-    nt.assert_equal(find_cmd('python'), sys.executable)
+    nt.assert_equal(find_cmd(python), sys.executable)
 
     
 @dec.skip_win32
@@ -102,30 +105,34 class SubProcessTestCase(TestCase, tt.TempFileMixin):
         self.mktmp('\n'.join(lines))
 
     def test_system(self):
-        status = system('python "%s"' % self.fname)
+        status = system('%s "%s"' % (python, self.fname))
         self.assertEqual(status, 0)
 
     def test_system_quotes(self):
-        status = system('python -c "import sys"')
+        status = system('%s -c "import sys"' % python)
         self.assertEqual(status, 0)
 
     def test_getoutput(self):
-        out = getoutput('python "%s"' % self.fname)
-        self.assertEqual(out, 'on stdout')
+        out = getoutput('%s "%s"' % (python, self.fname))
+        # we can't rely on the order the line buffered streams are flushed
+        try:
+            self.assertEqual(out, 'on stderron stdout')
+        except AssertionError:
+            self.assertEqual(out, 'on stdouton stderr')
 
     def test_getoutput_quoted(self):
-        out = getoutput('python -c "print (1)"')
+        out = getoutput('%s -c "print (1)"' % python)
         self.assertEqual(out.strip(), '1')
 
     #Invalid quoting on windows
     @dec.skip_win32
     def test_getoutput_quoted2(self):
-        out = getoutput("python -c 'print (1)'")
+        out = getoutput("%s -c 'print (1)'" % python)
         self.assertEqual(out.strip(), '1')
-        out = getoutput("python -c 'print (\"1\")'")
+        out = getoutput("%s -c 'print (\"1\")'" % python)
         self.assertEqual(out.strip(), '1')
 
-    def test_getoutput(self):
-        out, err = getoutputerror('python "%s"' % self.fname)
+    def test_getoutput_error(self):
+        out, err = getoutputerror('%s "%s"' % (python, self.fname))
         self.assertEqual(out, 'on stdout')
         self.assertEqual(err, 'on stderr')