Add UUID accessors

CHANGELOG.rst

 Unreleased changes
 ------------------
+* Adds ``.uuid`` attributes to ``OfflineReader`` and ``OnlineReader``
 
 Version 0
 ---------

km3io/offline.py

@@ -160,7 +160,7 @@ class OfflineReader:
         self._fobj = uproot.open(file_path)
         self._filename = file_path
         self._tree = self._fobj[MAIN_TREE_NAME]
-        self._uuid = binascii.hexlify(self._fobj._context.uuid)
+        self._uuid = binascii.hexlify(self._fobj._context.uuid).decode("ascii")
 
     @property
     def uuid(self):

km3io/online.py

@@ -116,7 +116,7 @@ class OnlineReader:
         self._events = None
         self._timeslices = None
         self._summaryslices = None
-        self._uuid = binascii.hexlify(self._fobj._context.uuid)
+        self._uuid = binascii.hexlify(self._fobj._context.uuid).decode("ascii")
 
     @property
     def uuid(self):

tests/test_offline.py

@@ -31,6 +31,9 @@ class TestOfflineReader(unittest.TestCase):
     def test_number_events(self):
         assert self.n_events == len(self.r.events)
 
+    def test_uuid(self):
+        assert self.r.uuid == "0001b192d888fcc711e9b4306cf09e86beef"
+
 
 class TestHeader(unittest.TestCase):
     def test_str_header(self):

tests/test_online.py

@@ -18,6 +18,11 @@ class TestOnlineReaderContextManager(unittest.TestCase):
             assert r._filename == ONLINE_FILE
 
 
+class TestUUID(unittest.TestCase):
+    def test_uuid(self):
+        assert OnlineReader(ONLINE_FILE).uuid == "00010c85603008c611ea971772f09e86beef"
+
+
 class TestOnlineEvents(unittest.TestCase):
     def setUp(self):
         self.events = OnlineReader(ONLINE_FILE).events