Refactor SNO finder

Signed-off-by: Adam.Dybbroe <a000680@c22526.ad.smhi.se>

pyorbital/sno_utils.py

@@ -40,6 +40,12 @@
 import logging
 
 
+class PlatformNotSupported(Exception):
+    """Exception error when platform is not supported."""
+
+    pass
+
+
 OSCAR_NAMES = {'npp': 'Suomi-NPP',
                'snpp': 'Suomi-NPP',
                'aqua': 'EOS-Aqua',
@@ -99,6 +105,13 @@ def __init__(self, platform_id, calipso_id, time_window, sno_min_thr, arc_len_mi
         self._tle_buffer_calipso = {}
         self._tle_buffer_other = {}
 
+        self._check_platforms()
+
+    def _check_platforms(self):
+        # Check if satellite is supported:
+        if OSCAR_NAMES.get(self.platform_id, self.platform_id).upper() not in SATELLITES.keys():
+            raise PlatformNotSupported(f"Platform {self.platform_id} not supported!")
+
     def set_configuration(self, configfile):
         """Set the basic configuration from yaml config file."""
         conf = get_config(configfile)
@@ -136,12 +149,6 @@ def get_snos_within_time_window(self):
         tle_dirs = self._conf['tle-dirs']
         tle_file_format = self._conf['tle-file-format']
 
-        import sys
-        # Check if satellite is supported:
-        if OSCAR_NAMES.get(self.platform_id, self.platform_id).upper() not in SATELLITES.keys():
-            LOG.error("Platform %s not supported!" % self.platform_id)
-            sys.exit()
-
         pobj = Parser(tle_file_format)
         for tledir in tle_dirs:
             filename_calipso = Path(tledir) / pobj.compose({'platform': self.calipso_id})
@@ -207,7 +214,7 @@ def get_snos_within_time_window(self):
 
             got_intersection_acurate = False
             arc_calipso_vector = get_arc_vector(tobj, timestep_plus_30s, calipso, self.arc_len_min)
-            arc_the_other_one_vector = get_arc_vector(tobj, timestep_plus_30s, the_other_one,  self.arc_len_min)
+            arc_the_other_one_vector = get_arc_vector(tobj, timestep_plus_30s, the_other_one, self.arc_len_min)
             # Approximate tracks with one arc each self.arc_len_min minutes.
             # For each pair of arcs check if they intersect.
             # There is atmost one intersection. Quit when we find it.

pyorbital/tests/test_snos.py

@@ -29,6 +29,7 @@
 from datetime import timezone
 from pyorbital.sno_utils import SNOfinder
 from pyorbital.sno_utils import check_overlapping_times
+from pyorbital.sno_utils import PlatformNotSupported
 # from pyorbital.config import get_config
 from pyorbital.tests.test_helper import get_dataframe_from_ascii
 from pyorbital.tests.test_helper import df2geojson
@@ -61,6 +62,21 @@
 """
 
 
+def test_snofinder_unsupported_platform(fake_yamlconfig_file, fake_tle_file1_calipso, fake_tle_file1_snpp):
+    """Test the SNO finder when one of the platform names are not supported."""
+    platform_one = 'PARASOL'
+    platform_two = 'calipso'
+    time_window = (dt.datetime(2014, 1, 3, tzinfo=timezone.utc),
+                   dt.datetime(2014, 1, 4, tzinfo=timezone.utc))
+    sno_min_thr = 2  # SNOs allowed to have 2 minute deviation between the two platforms
+
+    with pytest.raises(PlatformNotSupported) as exec_info:
+        _ = SNOfinder(platform_one, platform_two, time_window, sno_min_thr)
+
+    exception_raised = exec_info.value
+    assert str(exception_raised) == "Platform PARASOL not supported!"
+
+
 def test_get_snos_calipso_snpp(fake_yamlconfig_file, fake_tle_file1_calipso, fake_tle_file1_snpp):
     """Test finding calipso and SNPP SNOs within time window."""
     platform_one = 'snpp'