Non existed archive will not be fatal

Moved logic which check for archive file explicitly to extract method.
That way get_archiver will return archiver for not (yet) existed
archives.

fs_uae_wrapper/file_archive.py

@@ -21,16 +21,26 @@ class Archive(object):
         Create archive using self.archiver and parameters in self.ADD
         attribute
         """
-        return subprocess.call([self.archiver] + self.ADD +
-                               [arch_name, '.']) == 0
+        result = subprocess.call([self.archiver] + self.ADD + [arch_name, '.'])
+        if result != 0:
+            sys.stderr.write("Unable to create archive `%s'\n" % arch_name)
+            return False
+        return True
 
     def extract(self, arch_name):
         """
         Create archive using self.archiver and parameters in self.ADD
         attribute
         """
-        return subprocess.call([self.archiver] + self.EXTRACT +
-                               [arch_name]) == 0
+        if not os.path.exists(arch_name):
+            sys.stderr.write("Archive `%s' doesn't exists.\n" % arch_name)
+            return False
+
+        result = subprocess.call([self.archiver] + self.EXTRACT + [arch_name])
+        if result != 0:
+            sys.stderr.write("Unable to extract archive `%s'\n" % arch_name)
+            return False
+        return True
 
     def which(self):
         """
@@ -103,18 +113,18 @@ class RarArchive(Archive):
                              'supported by unrar.\n')
             return False
 
-        return subprocess.call([self.archiver] + self.ADD + [arch_name] +
-                               sorted(os.listdir('.'))) == 0
+        result = subprocess.call([self.archiver] + self.ADD + [arch_name] +
+                                 sorted(os.listdir('.')))
+        if result != 0:
+            sys.stderr.write("Unable to create archive `%s'\n" % arch_name)
+            return False
+        return True
 
 
-def get_archiver(filename):
-    """Return right class for provided archive filename"""
+def get_archiver(arch_name):
+    """Return right class for provided archive file name"""
 
-    if not os.path.exists(filename):
-        sys.stderr.write("Archive `%s' doesn't exists.\n" % filename)
-        return None
-
-    _, ext = os.path.splitext(filename)
+    _, ext = os.path.splitext(arch_name)
 
     archivers = {'.tar': TarArchive,
                  '.tgz': TarGzipArchive,
@@ -129,10 +139,13 @@ def get_archiver(filename):
 
     archiver = archivers.get(ext)
     if not archiver:
+        sys.stderr.write("Unable find archive type for `%s'\n" % arch_name)
         return None
 
     archobj = archiver()
     if archobj.archiver is None:
+        sys.stderr.write("Unable find executable for operating on files"
+                         " `*%s'\n" % ext)
         return None
 
     return archobj

tests/test_file_archive.py

@@ -1,7 +1,6 @@
 import os
-import sys
 import shutil
-from tempfile import mkstemp, mkdtemp
+from tempfile import mkdtemp
 from unittest import TestCase
 
 try:
@@ -10,7 +9,6 @@ except ImportError:
     import mock
 
 from fs_uae_wrapper import file_archive
-from fs_uae_wrapper import utils
 
 
 class TestArchive(TestCase):
@@ -30,10 +28,6 @@ class TestArchive(TestCase):
     def test_get_archiver(self):
         arch = file_archive.get_archiver('foobarbaz.cab')
         self.assertIsNone(arch)
-        with open('foobarbaz.cab', 'w') as fobj:
-            fobj.write('\n')
-        arch = file_archive.get_archiver('foobarbaz.cab')
-        self.assertIsNone(arch)
 
         with open('foobarbaz.tar', 'w') as fobj:
             fobj.write('\n')
@@ -56,6 +50,8 @@ class TestArchive(TestCase):
 
         call.reset_mock()
         call.return_value = 1
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
         self.assertFalse(arch.extract('foo'))
         call.assert_called_once_with(['false', 'x', 'foo'])
 
@@ -78,6 +74,9 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_tar(self, call, which):
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
+
         arch = file_archive.TarArchive()
         arch.archiver = 'tar'
         call.return_value = 0
@@ -129,6 +128,9 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_lha(self, call, which):
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
+
         arch = file_archive.LhaArchive()
         arch.archiver = 'lha'
         call.return_value = 0
@@ -144,6 +146,9 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_lzx(self, call, which):
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
+
         arch = file_archive.LzxArchive()
         arch.archiver = 'unlzx'
         call.return_value = 0
@@ -159,6 +164,9 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_7zip(self, call, which):
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
+
         arch = file_archive.SevenZArchive()
         arch.archiver = '7z'
         call.return_value = 0
@@ -174,6 +182,9 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_zip(self, call, which):
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
+
         arch = file_archive.ZipArchive()
         arch.archiver = '7z'
         call.return_value = 0
@@ -189,6 +200,7 @@ class TestArchive(TestCase):
     @mock.patch('fs_uae_wrapper.file_archive.Archive.which')
     @mock.patch('subprocess.call')
     def test_rar(self, call, which):
+
         arch = file_archive.RarArchive()
         arch.archiver = 'rar'
         call.return_value = 0
@@ -206,6 +218,8 @@ class TestArchive(TestCase):
         self.assertTrue(arch.create('foo.rar'))
         call.assert_called_once_with(['rar', 'a', 'foo.rar', 'bar', 'baz',
                                       'directory', 'foo'])
+        with open('foo', 'w') as fobj:
+            fobj.write('\n')
 
         call.reset_mock()
         call.return_value = 1