Add PeriodicCache

tests/test_periodiccache.py

@@ -0,0 +1,31 @@
+from freqtrade.configuration import PeriodicCache
+import time_machine
+
+
+def test_ttl_cache():
+
+    with time_machine.travel("2021-09-01 05:00:00 +00:00") as t:
+
+        cache = PeriodicCache(5, ttl=60)
+        cache1h = PeriodicCache(5, ttl=3600)
+
+        assert cache.timer() == 1630472400.0
+        cache['a'] = 1235
+        cache1h['a'] = 555123
+        assert 'a' in cache
+        assert 'a' in cache1h
+
+        t.move_to("2021-09-01 05:00:59 +00:00")
+        assert 'a' in cache
+        assert 'a' in cache1h
+
+        # Cache expired
+        t.move_to("2021-09-01 05:01:00 +00:00")
+        assert 'a' not in cache
+        assert 'a' in cache1h
+
+        t.move_to("2021-09-01 05:59:59 +00:00")
+        assert 'a' in cache1h
+
+        t.move_to("2021-09-01 06:00:00 +00:00")
+        assert 'a' not in cache1h