Check on real length of binary eventrecord

physio_cassette/physio_cassette.py

@@ -746,7 +746,8 @@ def __len__(self):
         if not self.is_binary:
             return self.data.n_measurements()
         elif self.data.n_measurements()>1:
-            return (self.data.n_measurements()-1)//2 
+            remainder = self.data.n_measurements() % 2 # Assess that the start/0 value may be overwritten
+            return (self.data.n_measurements()-remainder)//2 
         else:
             return 0 # Assuming a binary EventRecord with only the start/0 value to be empty
 

tests/test_eventrecord.py

@@ -0,0 +1,32 @@
+from datetime import datetime, timedelta
+
+import pytest
+
+from physio_cassette.physio_cassette import EventRecord
+
+
+class TestEventRecord:
+    @pytest.fixture
+    def len_binary(self):
+        yield 10
+
+    @pytest.fixture
+    def simple_binary_record(self, len_binary):
+        # Simple binary array
+        t0 = datetime.fromtimestamp(0)
+        input_array = [1,0]*len_binary
+        yield EventRecord.from_state_array('simple_binary', t0=t0, input_array=input_array, start_value=0)
+
+    @pytest.fixture
+    def simple_binary_nostart_record(self, len_binary):
+        # Binary array with start value covered by data
+        t0 = datetime.fromtimestamp(0)
+        input_array = [1,0]*len_binary
+        ts = [t0+timedelta(seconds=i) for i in range(len(input_array))]
+        yield EventRecord.from_state_array('simple_binary', t0=t0, input_array=input_array, ts_array=ts, start_value=0)   
+
+    def test_length(self, simple_binary_record, simple_binary_nostart_record, len_binary):
+
+        # Binary records return correct number of events even if start value changes
+        assert simple_binary_record.n_events==len_binary
+        assert simple_binary_nostart_record.n_events==len_binary