Whoosh tests: use a unique tempdir

This ensures that there's no way for results to persist across runs
and lets the OS clean up the mess if we fail catastrophically

The multiindex and regular whoosh tests will have different prefixes to ease
debugging

Author: acdha

tests/multipleindex_settings.py

@@ -1,4 +1,4 @@
-import os
+from tempfile import mkdtemp
 from settings import *
 
 INSTALLED_APPS += [
@@ -12,7 +12,7 @@
     },
     'whoosh': {
         'ENGINE': 'haystack.backends.whoosh_backend.WhooshEngine',
-        'PATH': os.path.join('tmp', 'test_whoosh_query'),
+        'PATH': mkdtemp(prefix='haystack-multipleindex-whoosh-tests-'),
         'EXCLUDED_INDEXES': ['multipleindex.search_indexes.BarIndex'],
     },
 }

tests/whoosh_settings.py

@@ -1,3 +1,4 @@
+from tempfile import mkdtemp
 import os
 from settings import *
 
@@ -8,8 +9,7 @@
 HAYSTACK_CONNECTIONS = {
     'default': {
         'ENGINE': 'haystack.backends.whoosh_backend.WhooshEngine',
-        'PATH': os.path.join('tmp', 'test_whoosh_query'),
+        'PATH': mkdtemp(prefix='haystack-whoosh-tests-'),
         'INCLUDE_SPELLING': True,
-        # 'STORAGE': 'ram',
     },
 }