Create the directory for a JsonableLog before trying to write it

manager/manager.py

@@ -16,6 +16,7 @@ class JsonableLog:
     """
     def __init__(self, pathname):
         self.pathname = pathname
+        os.makedirs(os.path.dirname(self.pathname), exist_ok=True)
         try:
             self.fd = open(self.pathname, "at")
         except FileNotFoundError:

tests/test_operationlog.py

@@ -48,4 +48,4 @@ class TestOperationLog(TestCase):
             oplog.log(ops.Noop())
             oplog.close()
 
-            self.assertFalse(os.path.exists(pathname))
+            self.assertTrue(os.path.exists(pathname))