Add missing imports for event sources (#991)

ctapipe/io/__init__.py

@@ -1,22 +1,30 @@
 from .array import get_array_layout
 from .eventseeker import EventSeeker
 from .eventsource import EventSource, event_source
-from .simteleventsource import SimTelEventSource
 from .hdf5tableio import HDF5TableReader, HDF5TableWriter
 from .tableio import TableWriter, TableReader
 
+# import event sources to make them visible to EventSource.from_url
+from .simteleventsource import SimTelEventSource
+from .lsteventsource import LSTEventSource
+from .nectarcameventsource import NectarCAMEventSource
+from .targetioeventsource import TargetIOEventSource
+
 from ctapipe.core.plugins import detect_and_import_io_plugins
 
 detect_and_import_io_plugins()
 
 __all__ = [
     'get_array_layout',
-    'SimTelEventSource',
     'HDF5TableWriter',
     'HDF5TableReader',
     'TableWriter',
     'TableReader',
     'EventSeeker',
     'EventSource',
     'event_source',
+    'SimTelEventSource',
+    'NectarCAMEventSource',
+    'LSTEventSource',
+    'TargetIOEventSource',
 ]

ctapipe/io/lsteventsource.py

@@ -24,8 +24,6 @@ class LSTEventSource(EventSource):
     EventSource for LST r0 data.
     """
 
-
-
     def __init__(self, config=None, tool=None, **kwargs):
 
         """

ctapipe/io/tests/test_available_sources.py

@@ -0,0 +1,17 @@
+def test_available_sources():
+    from ctapipe.io.eventsource import EventSource
+    from ctapipe.core import non_abstract_children
+
+    # make this before the explicit imports to make sure
+    # all classes are avaialble even if not explicitly imported
+    children = non_abstract_children(EventSource)
+
+    from ctapipe.io.simteleventsource import SimTelEventSource
+    from ctapipe.io.lsteventsource import LSTEventSource
+    from ctapipe.io.nectarcameventsource import NectarCAMEventSource
+    from ctapipe.io.targetioeventsource import TargetIOEventSource
+
+    assert SimTelEventSource in children
+    assert LSTEventSource in children
+    assert NectarCAMEventSource in children
+    assert TargetIOEventSource in children