Add third_party/pexpect

third_party/pexpect/tests/test_which.py

Index: third_party/pexpect/tests/test_which.py
diff --git a/third_party/pexpect/tests/test_which.py b/third_party/pexpect/tests/test_which.py
new file mode 100644
index 0000000000000000000000000000000000000000..f909214865c2e7bb57fc37bd5fc4198b47c2414a
--- /dev/null
+++ b/third_party/pexpect/tests/test_which.py
@@ -0,0 +1,274 @@
+# -*- coding: utf-8 -*-
+import subprocess
+import tempfile
+import shutil
+import errno
+import os
+
+import pexpect
+from . import PexpectTestCase
+
+import pytest
+
+
+class TestCaseWhich(PexpectTestCase.PexpectTestCase):
+    " Tests for pexpect.which(). "
+
+    def test_which_finds_ls(self):
+        " which() can find ls(1). "
+        exercise = pexpect.which("ls")
+        assert exercise is not None
+        assert exercise.startswith('/')
+
+    def test_os_defpath_which(self):
+        " which() finds an executable in $PATH and returns its abspath. "
+
+        bin_dir = tempfile.mkdtemp()
+        temp_obj = tempfile.NamedTemporaryFile(
+            suffix=u'.sh', prefix=u'ǝpoɔıun-',
+            dir=bin_dir, delete=False)
+        bin_path = temp_obj.name
+        fname = os.path.basename(temp_obj.name)
+        save_path = os.environ['PATH']
+        save_defpath = os.defpath
+
+        try:
+            # setup
+            os.environ['PATH'] = ''
+            os.defpath = bin_dir
+            with open(bin_path, 'w') as fp:
+                pass
+
+            # given non-executable,
+            os.chmod(bin_path, 0o400)
+
+            # exercise absolute and relative,
+            assert pexpect.which(bin_path) is None
+            assert pexpect.which(fname) is None
+
+            # given executable,
+            os.chmod(bin_path, 0o700)
+
+            # exercise absolute and relative,
+            assert pexpect.which(bin_path) == bin_path
+            assert pexpect.which(fname) == bin_path
+
+        finally:
+            # restore,
+            os.environ['PATH'] = save_path
+            os.defpath = save_defpath
+
+            # destroy scratch files and folders,
+            if os.path.exists(bin_path):
+                os.unlink(bin_path)
+            if os.path.exists(bin_dir):
+                os.rmdir(bin_dir)
+
+    def test_path_search_which(self):
+        " which() finds an executable in $PATH and returns its abspath. "
+        fname = 'gcc'
+        bin_dir = tempfile.mkdtemp()
+        bin_path = os.path.join(bin_dir, fname)
+        save_path = os.environ['PATH']
+        try:
+            # setup
+            os.environ['PATH'] = bin_dir
+            with open(bin_path, 'w') as fp:
+                pass
+
+            # given non-executable,
+            os.chmod(bin_path, 0o400)
+
+            # exercise absolute and relative,
+            assert pexpect.which(bin_path) is None
+            assert pexpect.which(fname) is None
+
+            # given executable,
+            os.chmod(bin_path, 0o700)
+
+            # exercise absolute and relative,
+            assert pexpect.which(bin_path) == bin_path
+            assert pexpect.which(fname) == bin_path
+
+        finally:
+            # restore,
+            os.environ['PATH'] = save_path
+
+            # destroy scratch files and folders,
+            if os.path.exists(bin_path):
+                os.unlink(bin_path)
+            if os.path.exists(bin_dir):
+                os.rmdir(bin_dir)
+
+    def test_which_follows_symlink(self):
+        " which() follows symlinks and returns its path. "
+        fname = 'original'
+        symname = 'extra-crispy'
+        bin_dir = tempfile.mkdtemp()
+        bin_path = os.path.join(bin_dir, fname)
+        sym_path = os.path.join(bin_dir, symname)
+        save_path = os.environ['PATH']
+        try:
+            # setup
+            os.environ['PATH'] = bin_dir
+            with open(bin_path, 'w') as fp:
+                pass
+            os.chmod(bin_path, 0o400)
+            os.symlink(bin_path, sym_path)
+
+            # should not be found because symlink points to non-executable
+            assert pexpect.which(symname) is None
+
+            # but now it should -- because it is executable
+            os.chmod(bin_path, 0o700)
+            assert pexpect.which(symname) == sym_path
+
+        finally:
+            # restore,
+            os.environ['PATH'] = save_path
+
+            # destroy scratch files, symlinks, and folders,
+            if os.path.exists(sym_path):
+                os.unlink(sym_path)
+            if os.path.exists(bin_path):
+                os.unlink(bin_path)
+            if os.path.exists(bin_dir):
+                os.rmdir(bin_dir)
+
+    def test_which_should_not_match_folders(self):
+        " Which does not match folders, even though they are executable. "
+        # make up a path and insert a folder that is 'executable', a naive
+        # implementation might match (previously pexpect versions 3.2 and
+        # sh versions 1.0.8, reported by @lcm337.)
+        fname = 'g++'
+        bin_dir = tempfile.mkdtemp()
+        bin_dir2 = os.path.join(bin_dir, fname)
+        save_path = os.environ['PATH']
+        try:
+            os.environ['PATH'] = bin_dir
+            os.mkdir(bin_dir2, 0o755)
+            # should not be found because it is not executable *file*,
+            # but rather, has the executable bit set, as a good folder
+            # should -- it should not be returned because it fails isdir()
+            exercise = pexpect.which(fname)
+            assert exercise is None
+
+        finally:
+            # restore,
+            os.environ['PATH'] = save_path
+            # destroy scratch folders,
+            for _dir in (bin_dir2, bin_dir,):
+                if os.path.exists(_dir):
+                    os.rmdir(_dir)
+
+    def test_which_should_match_other_group_user(self):
+        " which() returns executables by other, group, and user ownership. "
+        # create an executable and test that it is found using which() for
+        # each of the 'other', 'group', and 'user' permission bits.
+        fname = 'g77'
+        bin_dir = tempfile.mkdtemp()
+        bin_path = os.path.join(bin_dir, fname)
+        save_path = os.environ['PATH']
+        try:
+            # setup
+            os.environ['PATH'] = bin_dir
+
+            # an interpreted script requires the ability to read,
+            # whereas a binary program requires only to be executable.
+            #
+            # to gain access to a binary program, we make a copy of
+            # the existing system program echo(1).
+            bin_echo = None
+            for pth in ('/bin/echo', '/usr/bin/echo'):
+                if os.path.exists(pth):
+                    bin_echo = pth
+                    break
+            bin_which = None
+            for pth in ('/bin/which', '/usr/bin/which'):
+                if os.path.exists(pth):
+                    bin_which = pth
+                    break
+            if not bin_echo or not bin_which:
+                pytest.skip('needs `echo` and `which` binaries')
+            shutil.copy(bin_echo, bin_path)
+            isroot = os.getuid() == 0
+            for should_match, mode in (
+                # note that although the file may have matching 'group' or
+                # 'other' executable permissions, it is *not* executable
+                # because the current uid is the owner of the file -- which
+                # takes precedence
+                (False,  0o000),   # ----------, no
+                (isroot, 0o001),   # ---------x, no
+                (isroot, 0o010),   # ------x---, no
+                (True,   0o100),   # ---x------, yes
+                (False,  0o002),   # --------w-, no
+                (False,  0o020),   # -----w----, no
+                (False,  0o200),   # --w-------, no
+                (isroot, 0o003),   # --------wx, no
+                (isroot, 0o030),   # -----wx---, no
+                (True,   0o300),   # --wx------, yes
+                (False,  0o004),   # -------r--, no
+                (False,  0o040),   # ----r-----, no
+                (False,  0o400),   # -r--------, no
+                (isroot, 0o005),   # -------r-x, no
+                (isroot, 0o050),   # ----r-x---, no
+                (True,   0o500),   # -r-x------, yes
+                (False,  0o006),   # -------rw-, no
+                (False,  0o060),   # ----rw----, no
+                (False,  0o600),   # -rw-------, no
+                (isroot, 0o007),   # -------rwx, no
+                (isroot, 0o070),   # ----rwx---, no
+                (True,   0o700),   # -rwx------, yes
+                (isroot, 0o4001),  # ---S-----x, no
+                (isroot, 0o4010),  # ---S--x---, no
+                (True,   0o4100),  # ---s------, yes
+                (isroot, 0o4003),  # ---S----wx, no
+                (isroot, 0o4030),  # ---S-wx---, no
+                (True,   0o4300),  # --ws------, yes
+                (isroot, 0o2001),  # ------S--x, no
+                (isroot, 0o2010),  # ------s---, no
+                (True,   0o2100),  # ---x--S---, yes
+
+            ):
+                mode_str = '{0:0>4o}'.format(mode)
+
+                # given file mode,
+                os.chmod(bin_path, mode)
+
+                # exercise whether we may execute
+                can_execute = True
+                try:
+                    subprocess.Popen(fname).wait() == 0
+                except OSError as err:
+                    if err.errno != errno.EACCES:
+                        raise
+                    # permission denied
+                    can_execute = False
+
+                assert should_match == can_execute, (
+                    should_match, can_execute, mode_str)
+
+                # exercise whether which(1) would match
+                proc = subprocess.Popen((bin_which, fname),
+                                        env={'PATH': bin_dir},
+                                        stdout=subprocess.PIPE)
+                bin_which_match = bool(not proc.wait())
+                assert should_match == bin_which_match, (
+                    should_match, bin_which_match, mode_str)
+
+                # finally, exercise pexpect's which(1) matches
+                # the same.
+                pexpect_match = bool(pexpect.which(fname))
+
+                assert should_match == pexpect_match == bin_which_match, (
+                    should_match, pexpect_match, bin_which_match, mode_str)
+
+        finally:
+            # restore,
+            os.environ['PATH'] = save_path
+
+            # destroy scratch files and folders,
+            if os.path.exists(bin_path):
+                os.unlink(bin_path)
+            if os.path.exists(bin_dir):
+                os.rmdir(bin_dir)