Expand on tests/test_which.py

Mainly, regarding os.defpath, os.environ['PATH'],
absolute, relative, and symlinks.

1 files changed, 141 insertions, 33 deletions

diff --git a/tests/test_which.py b/tests/test_which.py
index 959816e..83575fb 100644
--- a/tests/test_which.py
+++ b/tests/test_which.py
@@ -5,30 +5,57 @@ import pexpect
 from . import PexpectTestCase
 
 
-class TestCaseMisc(PexpectTestCase.PexpectTestCase):
+class TestCaseWhich(PexpectTestCase.PexpectTestCase):
+    " Tests for pexpect.which(). "
 
-    def test_basic_which(self):
-        # should find at least 'ls' program, and it should begin with '/'
+    def test_which_finds_ls(self):
+        " which() can find ls(1). "
         exercise = pexpect.which("ls")
-        assert exercise is not None and exercise.startswith('/')
-
-    def test_which(self):
-        p = os.defpath
-        ep = os.environ['PATH']
-        os.defpath = ":/tmp"
-        os.environ['PATH'] = ":/tmp"
-        wp = pexpect.which("ticker.py")
-        assert wp == 'ticker.py'
-        os.defpath = "/tmp"
-        os.environ['PATH'] = "/tmp"
-        wp = pexpect.which("ticker.py")
-        assert wp is None
-        os.defpath = p
-        os.environ['PATH'] = ep
-
-    def test_absolute_which(self):
-        # make up a path and insert first a non-executable,
-        # then, make it executable, and assert we may which() find it.
+        assert exercise is not None
+        assert exercise.startswith('/')
+
+    def test_os_defpath_which(self):
+        " which() finds an executable in $PATH and returns its abspath. "
+        fname = 'cc'
+        bin_dir = tempfile.mkdtemp()
+        bin_path = os.path.join(bin_dir, fname)
+        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)
@@ -37,29 +64,72 @@ class TestCaseMisc(PexpectTestCase.PexpectTestCase):
             # setup
             os.environ['PATH'] = bin_dir
             with open(bin_path, 'w') as fp:
-                fp.write('#!/bin/sh\necho hello, world\n')
+                pass
+
+            # given non-executable,
             os.chmod(bin_path, 0o400)
 
-            # it should not be found because it is not executable
-            assert pexpect.which(fname) is None, fname
+            # exercise absolute and relative,
+            assert pexpect.which(bin_path) is None
+            assert pexpect.which(fname) is None
 
-            # but now it should -- because it is executable
+            # given executable,
             os.chmod(bin_path, 0o700)
-            assert pexpect.which(fname) == bin_path, (fname, bin_path)
+
+            # 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):
-        # make up a path and insert a folder, which is 'executable', which
-        # a naive implementation might match (previously pexpect versions
-        # 3.2 and sh versions 1.0.8, reported by @lcm337.)
+        " 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)
@@ -67,11 +137,11 @@ class TestCaseMisc(PexpectTestCase.PexpectTestCase):
         try:
             os.environ['PATH'] = bin_dir
             os.mkdir(bin_dir2, 0o755)
-            # it should not be found because it is not executable *file*,
+            # should not be found because it is not executable *file*,
             # but rather, has the executable bit set, as a good folder
-            # should -- it shouldn't be returned because it fails isdir()
+            # should -- it should not be returned because it fails isdir()
             exercise = pexpect.which(fname)
-            assert exercise is None, exercise
+            assert exercise is None
 
         finally:
             # restore,
@@ -80,3 +150,41 @@ class TestCaseMisc(PexpectTestCase.PexpectTestCase):
             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
+            with open(bin_path, 'w') as fp:
+                fp.write('#!/bin/sh\necho hello, world\n')
+            for should_match, mode in ((False, 0o000),
+                                       (True,  0o005),
+                                       (True,  0o050),
+                                       (True,  0o500),
+                                       (False, 0o004),
+                                       (False, 0o040),
+                                       (False, 0o400)):
+                os.chmod(bin_path, mode)
+
+                if not should_match:
+                    # should not be found because it is not executable
+                    assert pexpect.which(fname) is None
+                else:
+                    # should match full 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)