Report the name of an unreadable directory (#1523)

* Report the name of an unreadable directory.

  * src/alire/alire-index_on_disk.adb (New_Handler.Process_Local_Index):
      If the Path isn't a readable directory (e.g. because it doesn't
      exist), add it to the message in Outcome_Failure.
  * testsuite/tests/index/local-index-not-found/test.py: updated for
      new 'not a readable directory' report format.

* Handle Windows separator doubling.

src/alire/alire-index_on_disk.adb

@@ -173,7 +173,7 @@ package body Alire.Index_On_Disk is
          Dir : constant Virtual_File := Create (+Path);
       begin
          if not Dir.Is_Directory then
-            Result := Outcome_Failure ("Not a readable directory");
+            Result := Outcome_Failure ("Not a readable directory: " & Path);
             return New_Invalid_Index;
          end if;
 

testsuite/tests/index/local-index-not-found/test.py

@@ -3,14 +3,14 @@
 """
 
 import os
+import os.path
 import re
 
 from e3.fs import rm
 
 from drivers.alr import prepare_indexes, run_alr
 from drivers.asserts import assert_match
 
-
 for d in ('no-such-directory',
           'file://no-such-directory', ):
     rm('alr-config', recursive=True)
@@ -20,10 +20,11 @@
 
     path_excerpt = os.path.join('alr-config', 'indexes', 'bad_index',
                                 'index.toml')
+    separator = re.escape(os.path.sep)
     assert_match('ERROR: Cannot load metadata from .*{}:'
-                 ' Not a readable directory'
+                 ' Not a readable directory: .{}{}'
                  '\n'
-                 .format(re.escape(path_excerpt)),
+                 .format(re.escape(path_excerpt), separator, d),
                  p.out)
 
 print('SUCCESS')