Added os.chdir, os.getcwd, os.path.abspath. (#68)

* Implement os.chdir, os.getcwd.
* Implement os.path.abspath. Add _AssertEqual() to check not only values but also types.

lib/os/__init__.py

@@ -18,7 +18,7 @@
 from os import path
 import stat as stat_module
 import sys
-from __go__.os import Chmod, Environ, Remove, Stat
+from __go__.os import Chdir, Chmod, Environ, Getwd, Remove, Stat
 from __go__.path.filepath import Separator
 from __go__.grumpy import NewFileFromFD
 from __go__.syscall import Close, SYS_FCNTL, Syscall, F_GETFD
@@ -32,6 +32,12 @@ for var in Environ():
   environ[k] = v
 
 
+def chdir(path):
+  err = Chdir(path)
+  if err:
+    raise OSError(err.Error())
+
+
 def chmod(filepath, mode):
   # TODO: Support mode flags other than perms.
   err = Chmod(filepath, stat(filepath).st_mode & ~0o777 | mode & 0o777)
@@ -53,6 +59,13 @@ def fdopen(fd, mode='r'):  # pylint: disable=unused-argument
   return NewFileFromFD(fd)
 
 
+def getcwd():
+  dir, err = Getwd()
+  if err:
+    raise OSError(err.Error())
+  return dir
+
+
 def remove(filepath):
   if stat_module.S_ISDIR(stat(filepath).st_mode):
     raise OSError('Operation not permitted: ' + filepath)

lib/os/path.py

@@ -15,7 +15,18 @@
 """"Utilities for manipulating and inspecting OS paths."""
 
 from __go__.os import Stat
-from __go__.path.filepath import Clean, Dir as dirname, IsAbs as isabs, Join  # pylint: disable=g-multiple-import,unused-import
+from __go__.path.filepath import Abs, Clean, Dir as dirname, IsAbs as isabs, Join  # pylint: disable=g-multiple-import,unused-import
+
+
+def abspath(path):
+  result, err = Abs(path)
+  if err:
+    raise OSError(err.Error())
+  if isinstance(path, unicode):
+    # Grumpy compiler encoded the string into utf-8, so the result can be
+    # decoded using utf-8.
+    return unicode(result, 'utf-8')
+  return result
 
 
 def exists(path):
@@ -60,7 +71,5 @@ def join(*paths):
 def normpath(path):
   result = Clean(path)
   if isinstance(path, unicode):
-    # Grumpy compiler encoded the string into utf-8, so the result can be
-    # decoded using utf-8.
     return unicode(result, 'utf-8')
   return result

lib/os/path_test.py

@@ -22,6 +22,19 @@ import weetest
 import tempfile
 
 
+def _AssertEqual(a, b):
+  assert a == b
+  assert type(a) is type(b)
+
+
+def TestAbspath():
+  _AssertEqual(path.abspath('/a/b/c'), '/a/b/c')
+  _AssertEqual(path.abspath(u'/a/b/c'), u'/a/b/c')
+  _AssertEqual(path.abspath('/a/b/c/'), '/a/b/c')
+  _AssertEqual(path.abspath(u'/a/b/c/'), u'/a/b/c')
+  _AssertEqual(path.abspath('a/b/c'), path.normpath(os.getcwd() + '/a/b/c'))
+
+
 def TestDirname():
   assert path.dirname('/a/b/c') == '/a/b'
   assert path.dirname('/a/b/c/') == '/a/b/c'
@@ -85,16 +98,16 @@ def TestJoin():
 
 
 def TestNormPath():
-  assert path.normpath('abc/') == 'abc'
-  assert path.normpath('/a//b') == '/a/b'
-  assert path.normpath('abc/../123') == '123'
-  assert path.normpath('../abc/123') == '../abc/123'
-  assert path.normpath('x/y/./z') == 'x/y/z'
-  assert path.normpath(u'abc/') == u'abc'
-  assert path.normpath(u'/a//b') == u'/a/b'
-  assert path.normpath(u'abc/../123') == u'123'
-  assert path.normpath(u'../abc/123') == u'../abc/123'
-  assert path.normpath(u'x/y/./z') == u'x/y/z'
+  _AssertEqual(path.normpath('abc/'), 'abc')
+  _AssertEqual(path.normpath('/a//b'), '/a/b')
+  _AssertEqual(path.normpath('abc/../123'), '123')
+  _AssertEqual(path.normpath('../abc/123'), '../abc/123')
+  _AssertEqual(path.normpath('x/y/./z'), 'x/y/z')
+  _AssertEqual(path.normpath(u'abc/'), u'abc')
+  _AssertEqual(path.normpath(u'/a//b'), u'/a/b')
+  _AssertEqual(path.normpath(u'abc/../123'), u'123')
+  _AssertEqual(path.normpath(u'../abc/123'), u'../abc/123')
+  _AssertEqual(path.normpath(u'x/y/./z'), u'x/y/z')
 
 
 if __name__ == '__main__':

lib/os_test.py

@@ -20,6 +20,20 @@ import tempfile
 import weetest
 
 
+def TestChdirAndGetCwd():
+  path = os.getcwd()
+  os.chdir('.')
+  assert os.getcwd() == path
+  tempdir = tempfile.mkdtemp()
+  try:
+    os.chdir(tempdir)
+    assert tempdir in os.getcwd()
+  finally:
+    os.chdir(path)
+    os.rmdir(tempdir)
+    assert os.getcwd() == path
+
+
 def TestChmod():
   fd, path = tempfile.mkstemp()
   os.close(fd)