libbtrfsutil: use local mkfs.btrfs for tests if it exists

The system might not have mkfs installed at all.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Makefile

@@ -357,7 +357,7 @@ testsuite: btrfs-corrupt-block fssum
 	$(Q)cd tests && ./export-testsuite.sh
 
 ifeq ($(PYTHON_BINDINGS),1)
-test-libbtrfsutil: libbtrfsutil_python
+test-libbtrfsutil: libbtrfsutil_python mkfs.btrfs
 	$(Q)cd libbtrfsutil/python; \
 		LD_LIBRARY_PATH=../.. $(PYTHON) -m unittest discover -v tests
 

libbtrfsutil/python/tests/__init__.py

@@ -37,8 +37,12 @@ class BtrfsTestCase(unittest.TestCase):
             os.rmdir(self.mountpoint)
             raise e
 
+        if os.path.exists('../../mkfs.btrfs'):
+            mkfs = '../../mkfs.btrfs'
+        else:
+            mkfs = 'mkfs.btrfs'
         try:
-            subprocess.check_call(['mkfs.btrfs', '-q', self.image])
+            subprocess.check_call([mkfs, '-q', self.image])
             subprocess.check_call(['mount', '-o', 'loop', '--', self.image, self.mountpoint])
         except Exception as e:
             os.remove(self.image)