Merge pull request #105 from MichaelAquilina/fix_macosx

Dont crash on OSX because INotify is unsupported

README.rst

@@ -92,6 +92,9 @@ If you wish to synchronise your targets continiously, use the ``daemon`` command
 
     $ s4 daemon myfolder1
 
+NOTE: This command is only supported on machines that can run INotify. This typically means
+Linux based operating systems.
+
 
 Handling Conflicts
 ------------------

s4/commands/daemon_command.py

@@ -1,14 +1,24 @@
 #! -*- encoding: utf-8 -*-
 from collections import defaultdict
 
-from inotify_simple import flags
+# Dont crash on import if the underlying operating system does not support INotify
+try:
+    from inotify_simple import flags
+    from s4.inotify_recursive import INotifyRecursive
+    supported = True
+except OSError:
+    supported = False
 
 from s4.commands import Command
-from s4.inotify_recursive import INotifyRecursive
 
 
 class DaemonCommand(Command):
     def run(self, terminator=lambda x: False):
+        if not supported:
+            self.logger.info('Cannot run INotify on your operating system')
+            self.logger.info('Only Linux machines are officially supported for this command')
+            return
+
         all_targets = list(self.config['targets'].keys())
         if not self.args.targets:
             targets = all_targets

tests/commands/test_daemon_command.py

@@ -31,6 +31,22 @@ def single_term(self, index):
         """Simple terminator for the daemon command"""
         return index >= 1
 
+    @mock.patch('s4.commands.daemon_command.supported', False)
+    def test_os_not_supported(self, INotifyRecursive, SyncWorker, capsys):
+        args = argparse.Namespace(targets=None, conflicts='ignore', read_delay=0)
+
+        command = DaemonCommand(args, {}, create_logger())
+        command.run(terminator=self.single_term)
+
+        out, err = capsys.readouterr()
+        assert out == ''
+        assert err == (
+            'Cannot run INotify on your operating system\n'
+            'Only Linux machines are officially supported for this command\n'
+        )
+        assert SyncWorker.call_count == 0
+        assert INotifyRecursive.call_count == 0
+
     @pytest.mark.timeout(5)
     def test_no_targets(self, INotifyRecursive, SyncWorker, capsys):
         args = argparse.Namespace(targets=None, conflicts='ignore', read_delay=0)