#!/usr/bin/python # # relpath.py # R.Barran 30/08/2004 import os def relpath(target, base=os.curdir): """ Return a relative path to the target from either the current dir or an optional base dir. Base can be a directory specified either as absolute or relative to current dir. """ if not os.path.exists(target): raise OSError, 'Target does not exist: '+target if not os.path.isdir(base): raise OSError, 'Base is not a directory or does not exist: '+base base_list = (os.path.abspath(base)).split(os.sep) target_list = (os.path.abspath(target)).split(os.sep) # On the windows platform the target may be on a completely different drive from the base. if os.name in ['nt','dos','os2'] and base_list[0] <> target_list[0]: raise OSError, 'Target is on a different drive to base. Target: '+target_list[0].upper()+', base: '+base_list[0].upper() # Starting from the filepath root, work out how much of the filepath is # shared by base and target. for i in range(min(len(base_list), len(target_list))): if base_list[i] <> target_list[i]: break else: # If we broke out of the loop, i is pointing to the first differing path elements. # If we didn't break out of the loop, i is pointing to identical path elements. # Increment i so that in all cases it points to the first differing path elements. i+=1 rel_list = [os.pardir] * (len(base_list)-i) + target_list[i:] return os.path.join(*rel_list) --- 8< --- snip --- 8< --- snip --- 8< --- snip --- 8< --- #!/usr/bin/python # # relpath_test.py # R.Barran 30/08/2004 """Unit test the relative path function""" import relpath,unittest import tempfile,os,shutil,sys def FmtPath(testpath): """Format a file path in os.specific format""" return testpath.replace('/',os.sep) def CreateTempFile(filename): f = open(filename,'w') f.close() class relpath_tests(unittest.TestCase): def setUp(self): """Prepare test environment (basic setup shared by all tests)""" # Determine where the temp directory is and run the tests there self.TempDir = tempfile.gettempdir() + os.sep + 'relpath_tests_dir' try: shutil.rmtree(self.TempDir) except: pass os.mkdir(self.TempDir) os.chdir(self.TempDir) # Create directory structure os.makedirs('a/b/c/') os.makedirs('a1/b1/c1/d1') # Create a couple of files to point to CreateTempFile('file1') CreateTempFile('a/b/file2') CreateTempFile('a1/b1/c1/d1/file3') def tearDown(self): """Bin the temp test dir and everything in it""" os.chdir(self.TempDir) os.chdir(os.pardir) shutil.rmtree('relpath_tests_dir') # # Checking for valid input # def testInvalidTargetName(self): """Should fail if the target does not exist """ self.assertRaises(OSError, relpath.relpath, 'a/nofilehere.txt') def testNoTargetName(self): """Should fail if the target is not supplied """ self.assertRaises(OSError, relpath.relpath, '') def testInvalidBasePath(self): """Should fail if the base path specified does not exist """ self.assertRaises(OSError, relpath.relpath, 'file1', 'this/path/does/not/exist') def testBasePathIsNotADir(self): """Should fail if the base is anything other than a directory """ self.assertRaises(OSError, relpath.relpath, 'file1', 'a/b/file2') def testTargetOnDifferentDrive(self): """On windows platform the target must be on the same drive as the base point.""" if sys.platform == 'win32': self.assertRaises(OSError, relpath.relpath, 'z:/file99') # # Tests with only the target specified (no base) # def testTargetinCurrDir(self): """Target is in the current directory""" self.assertEqual(relpath.relpath('file1'), 'file1') self.assertEqual(relpath.relpath(os.path.abspath('file1')), 'file1') def testTarget2DirsDown(self): """Target is 2 directories down""" self.assertEqual(relpath.relpath('a/b/file2'), FmtPath('a/b/file2')) self.assertEqual(relpath.relpath(os.path.abspath('a/b/file2')), FmtPath('a/b/file2')) def testTarget2DirsUp(self): """Target is 2 directories up""" os.chdir('a/b') self.assertEqual(relpath.relpath('../../file1'), FmtPath('../../file1')) self.assertEqual(relpath.relpath(os.path.abspath('../../file1')), FmtPath('../../file1')) def testTarget2Up4Down(self): """Target is 2 directories up then down 4""" os.chdir('a/b') self.assertEqual(relpath.relpath('../../a1/b1/c1/d1/file3'), FmtPath('../../a1/b1/c1/d1/file3')) self.assertEqual(relpath.relpath(os.path.abspath('../../a1/b1/c1/d1/file3')), FmtPath('../../a1/b1/c1/d1/file3')) self.assertEqual(relpath.relpath(self.TempDir+'/a1/b1/c1/d1/file3'), FmtPath('../../a1/b1/c1/d1/file3')) # # Tests with target and base specified # def testTargetinCurrDir_c1(self): """Target is in the current directory, base is in c1""" self.assertEqual(relpath.relpath('file1','a1/b1/c1'), FmtPath('../../../file1')) def testTarget1DirUp_c1(self): """Target is 1 directory up from current dir, base is in c1""" # Result should be same as previous test, this is just a way of checking that # changing the curr dir has no influence on the result. os.chdir('a') self.assertEqual(relpath.relpath(self.TempDir+'/file1',self.TempDir+'/a1/b1/c1'), FmtPath('../../../file1')) def testTarget2DirsDown_c1(self): """Target is 2 directories down from current dir, base is in c1""" os.chdir('a') self.assertEqual(relpath.relpath('b/file2',self.TempDir+'/a1/b1/c1'), FmtPath('../../../a/b/file2')) # # This final test is a bit different, it loops relpath 10000 times # and can be used for rough performance testing of different versions of # relpath # #def testSpeedTests(self): # for i in range(10000): # os.chdir(self.TempDir) # self.assertEqual(relpath.relpath('file1','a1/b1/c1'), FmtPath('../../../file1')) # self.assertEqual(relpath.relpath('a/b/file2'), FmtPath('a/b/file2')) # os.chdir('a') # self.assertEqual(relpath.relpath('b/file2',self.TempDir+'/a1/b1/c1'), FmtPath('../../../a/b/file2')) if __name__ == "__main__": unittest.main()