Merge branch 'fix-FilterAlgorithm-get_nearest_time' into 'master'

Function get_nearest_time() behaves as expected now

See merge request !338

geomagio/algorithm/FilterAlgorithm.py

@@ -64,24 +64,29 @@ STEPS = [
 
 
 def get_nearest_time(step, output_time, left=True):
+
+    # nearest allowed timestamp "left" of output_time
     interval_start = output_time - (
         output_time.timestamp % step["output_sample_period"]
     )
-    # shift interval right if needed
-    if interval_start != output_time and not left:
-        interval_start += step["output_sample_period"]
-    # position center of filter, data around interval
+
     half_width = get_step_time_shift(step)
+
     if step["type"] == "average":
-        filter_center = interval_start + half_width
-        data_start = interval_start
-        data_end = (interval_start + step["output_sample_period"]) - step[
-            "input_sample_period"
-        ]
+        interval_start += half_width
+
+    # shift interval if needed
+    if left:
+        if interval_start > output_time:
+            interval_start -= step["output_sample_period"]
     else:
-        filter_center = interval_start
-        data_start = filter_center - half_width
-        data_end = filter_center + half_width
+        if interval_start < output_time:
+            interval_start += step["output_sample_period"]
+
+    filter_center = interval_start
+    data_start = filter_center - half_width
+    data_end = filter_center + half_width
+
     return {
         "time": filter_center,
         "data_start": data_start,

test/algorithm_test/FilterAlgorithm_test.py

@@ -313,7 +313,7 @@ def test_get_nearest__oneday_average():
     f = FilterAlgorithm(input_sample_period=60.0, output_sample_period=86400.0)
     step = f.get_filter_steps()[0]
     time = UTCDateTime("2020-08-20T01:00:00")
-    aligned = get_nearest_time(step=step, output_time=time)
+    aligned = get_nearest_time(step=step, output_time=time, left=False)
     # filter is average for day, should be first/last minute samples of 2020-08-20
     assert_equal(aligned["data_start"], UTCDateTime("2020-08-20T00:00:00"))
     assert_equal(aligned["time"], UTCDateTime("2020-08-20T11:59:30"))