Handle libmagic versions that don't support MAGIC_EXTENSION

extension support was added to libmagic in 2015 in
9190a18d09f25fb0ca6abe1fcbdba780f5077e45.  This change:

 - updates the test to handle various verions that return garbage /
   empty string.s
- throws an exception in magic.Magic if extension support is requested
  and we know its not supported.

1 files changed, 4 insertions, 0 deletions

diff --git a/magic.py b/magic.py
index 773e4ae..aab7987 100644
--- a/magic.py
+++ b/magic.py
@@ -70,6 +70,10 @@ class Magic:
 
         magic_load(self.cookie, magic_file)
 
+        # MAGIC_EXTENSION was added in 523 or 524, so bail if
+        # it doesn't appear to be available
+        if extension and (not _has_version or version() < 524):
+            raise NotImplementedError('MAGIC_EXTENSION is not supported in this version of libmagic')
 
         # For https://github.com/ahupp/python-magic/issues/190
         # libmagic has fixed internal limits that some files exceed, causing