mock 'time()' in cache tests

instead of calling 'sleep()' to let time advance.

This shortens the time needed to run those tests,
and ensures consistent results.
(Tests would randomly fail when using 'sleep()')

gallery_dl/cache.py

@@ -57,7 +57,7 @@ class MemoryCacheDecorator(CacheDecorator):
             value, expires = self.cache[key]
         except KeyError:
             expires = 0
-        if expires < timestamp:
+        if expires <= timestamp:
             value = self.func(*args, **kwargs)
             expires = timestamp + self.maxage
             self.cache[key] = value, expires

test/test_cache.py

@@ -10,8 +10,8 @@
 import os
 import sys
 import unittest
+from unittest.mock import patch
 
-import time
 import tempfile
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
@@ -86,32 +86,50 @@ class TestCache(unittest.TestCase):
         self.assertEqual(ka(9, 9, 2), 6)
 
     def test_expires_mem(self):
-        @cache.memcache(maxage=1)
+        @cache.memcache(maxage=2)
         def ex(a, b, c):
             return a+b+c
 
-        self.assertEqual(ex(1, 1, 1), 3)
-        self.assertEqual(ex(2, 2, 2), 3)
-        self.assertEqual(ex(3, 3, 3), 3)
+        with patch("time.time") as tmock:
+            tmock.return_value = 0.001
+            self.assertEqual(ex(1, 1, 1), 3)
+            self.assertEqual(ex(2, 2, 2), 3)
+            self.assertEqual(ex(3, 3, 3), 3)
 
-        time.sleep(2)
-        self.assertEqual(ex(3, 3, 3), 9)
-        self.assertEqual(ex(2, 2, 2), 9)
-        self.assertEqual(ex(1, 1, 1), 9)
+            # value is still cached after 1 second
+            tmock.return_value += 1.0
+            self.assertEqual(ex(3, 3, 3), 3)
+            self.assertEqual(ex(2, 2, 2), 3)
+            self.assertEqual(ex(1, 1, 1), 3)
+
+            # new value after 'maxage' seconds
+            tmock.return_value += 1.0
+            self.assertEqual(ex(3, 3, 3), 9)
+            self.assertEqual(ex(2, 2, 2), 9)
+            self.assertEqual(ex(1, 1, 1), 9)
 
     def test_expires_db(self):
-        @cache.cache(maxage=1)
+        @cache.cache(maxage=2)
         def ex(a, b, c):
             return a+b+c
 
-        self.assertEqual(ex(1, 1, 1), 3)
-        self.assertEqual(ex(2, 2, 2), 3)
-        self.assertEqual(ex(3, 3, 3), 3)
-
-        time.sleep(2)
-        self.assertEqual(ex(3, 3, 3), 9)
-        self.assertEqual(ex(2, 2, 2), 9)
-        self.assertEqual(ex(1, 1, 1), 9)
+        with patch("time.time") as tmock:
+            tmock.return_value = 0.999
+            self.assertEqual(ex(1, 1, 1), 3)
+            self.assertEqual(ex(2, 2, 2), 3)
+            self.assertEqual(ex(3, 3, 3), 3)
+
+            # value is still cached after 1 second
+            tmock.return_value += 1.0
+            self.assertEqual(ex(3, 3, 3), 3)
+            self.assertEqual(ex(2, 2, 2), 3)
+            self.assertEqual(ex(1, 1, 1), 3)
+
+            # new value after 'maxage' seconds
+            tmock.return_value += 1.0
+            self.assertEqual(ex(3, 3, 3), 9)
+            self.assertEqual(ex(2, 2, 2), 9)
+            self.assertEqual(ex(1, 1, 1), 9)
 
     def test_update_mem_simple(self):
         @cache.memcache(keyarg=0)