Let tests pass without a PATH

catalyst ran into some issues where stem's tests didn't pass on his setup...

  https://trac.torproject.org/projects/tor/ticket/22301

Tests now pass when I run...

  % env -i ./run_tests.py --all --tor ../tor/src/or/tor

4 files changed, 13 insertions, 8 deletions

diff --git a/stem/util/system.py b/stem/util/system.py
index 4b705f34..7b315169 100644
--- a/stem/util/system.py
+++ b/stem/util/system.py
@@ -247,6 +247,8 @@ def is_available(command, cached=True):
     return True
   elif cached and command in CMD_AVAILABLE_CACHE:
     return CMD_AVAILABLE_CACHE[command]
+  elif 'PATH' not in os.environ:
+    return False  # lacking a path will cause find_executable() to internally fail
   else:
     cmd_exists = distutils.spawn.find_executable(command) is not None
     CMD_AVAILABLE_CACHE[command] = cmd_exists
diff --git a/test/integ/installation.py b/test/integ/installation.py
index 1cb9471f..16da8179 100644
--- a/test/integ/installation.py
+++ b/test/integ/installation.py
@@ -20,6 +20,7 @@ INSTALL_MISMATCH_MSG = "Running 'python setup.py sdist' doesn't match our git co
 BASE_INSTALL_PATH = '/tmp/stem_test'
 DIST_PATH = os.path.join(test.STEM_BASE, 'dist')
 SETUP_THREAD, INSTALL_FAILURE, INSTALL_PATH, SDIST_FAILURE = None, None, None, None
+PYTHON_EXE = sys.executable if sys.executable else 'python'
 
 
 def setup():
@@ -35,12 +36,10 @@ def setup():
     original_cwd = os.getcwd()
 
     try:
-      os.chdir(test.STEM_BASE)
-
       try:
         os.chdir(test.STEM_BASE)
-        stem.util.system.call('%s setup.py install --prefix %s' % (sys.executable, BASE_INSTALL_PATH), timeout = 60)
-        stem.util.system.call('%s setup.py clean --all' % sys.executable, timeout = 60)  # tidy up the build directory
+        stem.util.system.call('%s setup.py install --prefix %s' % (PYTHON_EXE, BASE_INSTALL_PATH), timeout = 60)
+        stem.util.system.call('%s setup.py clean --all' % PYTHON_EXE, timeout = 60)  # tidy up the build directory
         site_packages_paths = glob.glob('%s/lib*/*/site-packages' % BASE_INSTALL_PATH)
 
         if len(site_packages_paths) != 1:
@@ -52,7 +51,7 @@ def setup():
 
       if not os.path.exists(DIST_PATH):
         try:
-          stem.util.system.call('%s setup.py sdist' % sys.executable, timeout = 60)
+          stem.util.system.call('%s setup.py sdist' % PYTHON_EXE, timeout = 60)
         except Exception as exc:
           SDIST_FAILURE = exc
       else:
@@ -121,7 +120,7 @@ class TestInstallation(unittest.TestCase):
     if INSTALL_FAILURE:
       raise INSTALL_FAILURE
 
-    self.assertEqual(stem.__version__, stem.util.system.call([sys.executable, '-c', "import sys;sys.path.insert(0, '%s');import stem;print(stem.__version__)" % INSTALL_PATH])[0])
+    self.assertEqual(stem.__version__, stem.util.system.call([PYTHON_EXE, '-c', "import sys;sys.path.insert(0, '%s');import stem;print(stem.__version__)" % INSTALL_PATH])[0])
     _assert_has_all_files(INSTALL_PATH)
 
   @test.require.only_run_once
diff --git a/test/integ/process.py b/test/integ/process.py
index 1ca0f706..95c14cbd 100644
--- a/test/integ/process.py
+++ b/test/integ/process.py
@@ -96,8 +96,8 @@ class TestProcess(unittest.TestCase):
     hush to cut it down.
     """
 
-    output = self.run_tor('--hush', '--hash-password', 'my_password')
-    self.assertTrue(re.match('^16:[0-9A-F]{58}\n$', output))
+    output = self.run_tor('--hush', '--hash-password', 'my_password').splitlines()[-1]
+    self.assertTrue(re.match('^16:[0-9A-F]{58}$', output))
 
     # I'm not gonna even pretend to understand the following. Ported directly
     # from tor's test_cmdline_args.py.
diff --git a/test/integ/util/system.py b/test/integ/util/system.py
index 912251b9..07d7d752 100644
--- a/test/integ/util/system.py
+++ b/test/integ/util/system.py
@@ -66,9 +66,11 @@ require_single_tor_instance = test.require.needs(_is_single_tor_running, 'multip
 require_control_port = test.require.needs(_has_port, 'test instance has no port')
 require_linux = test.require.needs(_is_linux, 'linux only')
 require_bsd = test.require.needs(stem.util.system.is_bsd, 'bsd only')
+require_path = test.require.needs(lambda: 'PATH' in os.environ, 'requires PATH')
 
 
 class TestSystem(unittest.TestCase):
+  @require_path
   def test_is_available(self):
     """
     Checks the stem.util.system.is_available function.
@@ -99,6 +101,7 @@ class TestSystem(unittest.TestCase):
     self.assertTrue(stem.util.system.is_running(tor_cmd) or stem.util.system.is_running('tor.real'))
     self.assertFalse(stem.util.system.is_running('blarg_and_stuff'))
 
+  @require_path
   @require_single_tor_instance
   def test_pid_by_name(self):
     """
@@ -312,6 +315,7 @@ class TestSystem(unittest.TestCase):
     os.rmdir(tmpdir)
     self.assertEqual(None, stem.util.system.pid_by_open_file(tmpdir))
 
+  @require_path
   def test_pids_by_user(self):
     """
     Checks the stem.util.system.pids_by_user function.