Fix the is_channel_running bug

handel/interface.py

@@ -150,7 +150,11 @@ def is_channel_running(channel):
     running = ffi.new('short *')
     code = handel.xiaGetRunData(channel, b'run_active', running)
     check_error(code)
-    return bool(running[0])
+    # It turns out running contains 2 bits of information
+    # - bit 0: whether the channel is acquiring
+    # - bit 1: whether the channel is running (in the start_run/stop_run sense)
+    # We're interested in the first bit of information here
+    return bool(running[0] & 0x1)
 
 
 def is_running():

tests/test_interface.py

@@ -226,6 +226,7 @@ def test_get_spectrums(interface):
 
 
 def test_is_channel_running(interface):
+    # First test
     m = interface.handel.xiaGetRunData
 
     def side_effect(channel, dtype, arg):
@@ -237,7 +238,23 @@ def test_is_channel_running(interface):
     arg = m.call_args[0][2]
     m.assert_called_once_with(2, b'run_active', arg)
     # Make sure errors have been checked
-    interface.check_error.assert_called_with(0)
+    interface.check_error.assert_called_once_with(0)
+
+    # Second test
+    m.reset_mock()
+    interface.check_error.reset_mock()
+
+    def side_effect(channel, dtype, arg):
+        arg[0] = 2  # 2 is actually a valid value for a non-running channel
+        return 0
+
+    m.side_effect = side_effect
+    assert interface.is_channel_running(2) is False
+    arg = m.call_args[0][2]
+    m.assert_called_once_with(2, b'run_active', arg)
+    # Make sure errors have been checked
+    interface.check_error.assert_called_once_with(0)
+
 
 
 def test_is_running(interface):