Use time instead of datetime

plasma/node.py

@@ -1,5 +1,5 @@
 from collections import namedtuple
-from datetime import datetime
+import time
 from math import isclose
 import sys
 
@@ -70,7 +70,7 @@ def __init__(self, payload=None, x=None, y=None, width=None, height=None):
         self._height = height
         self._size = None
         self.children = []
-        self.last_accessed = datetime.min
+        self.last_accessed = 0
         self.parent = None
         self.restorables = {}
 
@@ -406,7 +406,7 @@ def flexible(self):
         return all((any(gc.flexible for gc in c) or c.is_leaf) for c in self)
 
     def access(self):
-        self.last_accessed = datetime.now()
+        self.last_accessed = time.time()
         try:
             self.parent.access()
         except AttributeError:
@@ -460,7 +460,7 @@ def close_neighbor(self, direction):
         if not nodes:
             return None
         most_recent = max(nodes, key=lambda n: n.last_accessed)
-        if most_recent.last_accessed > datetime.min:
+        if most_recent.last_accessed > 0:
             return most_recent
         if direction in [UP, DOWN]:
             match = lambda n: n.x <= self.x_center <= n.x_end

tests/test_layout.py

@@ -1,7 +1,7 @@
-from datetime import datetime
 from pathlib import Path
 from pytest import fixture, mark
 import sys
+import time
 
 from plasma import Plasma
 from plasma.node import Node
@@ -74,7 +74,7 @@ def test_access(self, root):
         layout = Plasma()
         layout.root = root
         layout.add('a')
-        now = datetime.now()
+        now = time.time()
         assert layout.root.find_payload('a').last_accessed < now
         layout.focus('a')
         assert layout.root.find_payload('a').last_accessed > now