Outputs cache, clear and interpolate data

Preparation to solve build new scheduling algorithm. See #78 (closed).

Use the ping mechanism to let outputs know their targets.

Outputs record pull time per target to determine data to store/clear. Store data, and clear after pull what can't be pulled anymore with strictly increasing pull time per target.

Outputs do nearest interpolation on pull and throw an arror when out of the data range.

Fixes #76 (closed)

tests/core/test_sdk.py

@@ -3,7 +3,7 @@ Unit tests for the sdk implementations.
 """
 import logging
 import unittest
-from datetime import datetime
+from datetime import datetime, timedelta
 
 import finam as fm
 from finam import (
@@ -16,6 +16,7 @@ from finam import (
     FinamMetaDataError,
     FinamNoDataError,
     FinamStatusError,
+    FinamTimeError,
     Info,
     Input,
     NoGrid,
@@ -227,6 +228,103 @@ class TestOutput(unittest.TestCase):
 
         self.assertEqual(out._connected_inputs, {ada: None})
 
+    def test_cache_data(self):
+        t = datetime(2000, 1, 1)
+        info = Info(time=t, grid=NoGrid())
+
+        out = Output(name="Output")
+        inp = Input(name="Input")
+
+        out >> inp
+
+        inp.ping()
+
+        out.push_info(info)
+        inp.exchange_info(info)
+
+        self.assertEqual(out._connected_inputs, {inp: None})
+
+        out.push_data(1, t)
+        self.assertEqual(out.data, [(t, 1)])
+
+        with self.assertRaises(FinamTimeError):
+            data = inp.pull_data(t - timedelta(hours=1))
+        with self.assertRaises(FinamTimeError):
+            data = inp.pull_data(t + timedelta(hours=1))
+
+        data = inp.pull_data(t)
+        self.assertEqual(out.data, [(t, 1)])
+        self.assertEqual(data, 1)
+
+        t2 = t + timedelta(days=1)
+        out.push_data(2, t2)
+        self.assertEqual(out.data, [(t, 1), (t2, 2)])
+
+        with self.assertRaises(FinamTimeError):
+            data = inp.pull_data(t - timedelta(hours=1))
+        with self.assertRaises(FinamTimeError):
+            data = inp.pull_data(t2 + timedelta(hours=1))
+
+        self.assertEqual(inp.pull_data(t), 1)
+        self.assertEqual(inp.pull_data(t + timedelta(hours=0)), 1)
+        self.assertEqual(inp.pull_data(t + timedelta(hours=11)), 1)
+        self.assertEqual(inp.pull_data(t + timedelta(hours=12)), 2)
+
+        self.assertEqual(len(out.data), 2)
+        self.assertEqual(inp.pull_data(t2), 2)
+        self.assertEqual(len(out.data), 1)
+
+        out.push_data(3, t + timedelta(days=2))
+        out.push_data(4, t + timedelta(days=3))
+        out.push_data(5, t + timedelta(days=4))
+
+        self.assertEqual(len(out.data), 4)
+        self.assertEqual(inp.pull_data(t + timedelta(days=2)), 3)
+        self.assertEqual(len(out.data), 3)
+
+    def test_cache_data_multi(self):
+        t = datetime(2000, 1, 1)
+        info = Info(time=t, grid=NoGrid())
+
+        out = Output(name="Output")
+        in1 = Input(name="Input")
+        in2 = Input(name="Input")
+
+        out >> in1
+        out >> in2
+
+        in1.ping()
+        in2.ping()
+
+        out.push_info(info)
+        in1.exchange_info(info)
+        in2.exchange_info(info)
+
+        for i in range(10):
+            out.push_data(i + 1, t + timedelta(days=i))
+
+        self.assertEqual(len(out.data), 10)
+
+        in1.pull_data(datetime(2000, 1, 3))
+        self.assertEqual(len(out.data), 10)
+
+        in2.pull_data(datetime(2000, 1, 1))
+        self.assertEqual(len(out.data), 10)
+
+        in2.pull_data(datetime(2000, 1, 2))
+        self.assertEqual(len(out.data), 9)
+
+        in2.pull_data(datetime(2000, 1, 8))
+        self.assertEqual(len(out.data), 8)
+
+        in1.pull_data(datetime(2000, 1, 8))
+        self.assertEqual(len(out.data), 3)
+
+        in1.pull_data(datetime(2000, 1, 10))
+        self.assertEqual(len(out.data), 3)
+        in2.pull_data(datetime(2000, 1, 10))
+        self.assertEqual(len(out.data), 1)
+
 
 class TestInput(unittest.TestCase):
     def test_fail_set_source(self):