Add AIS type 23 regression test.

Also fix type 16 interpretation in the Python decoder.

3 files changed, 25 insertions, 5 deletions

diff --git a/devtools/ais.py b/devtools/ais.py
index 44a8f44e..0700e5f5 100755
--- a/devtools/ais.py
+++ b/devtools/ais.py
@@ -406,13 +406,13 @@ type15 = (
 
 type16 = (
     spare(2),
-    bitfield("mmsi1",     30, 'unsigned', 0, "Interrogated MMSI"),
+    bitfield("mmsi1",     30, 'unsigned', 0, "Interrogated MMSI 1"),
     bitfield("offset1  ", 12, 'unsigned', 0, "First slot offset"),
-    bitfield("increment1",10, 'unsigned', 0, "Slot increment"),
+    bitfield("increment1",10, 'unsigned', 0, "First slot increment"),
     spare(2),
-    bitfield("mmsi2",     30, 'unsigned', 0, "Interrogated MMSI"),
-    bitfield("offset2",   12, 'unsifned', 0, "First slot offset"),
-    bitfield("increment2",10, 'unsigned', 0, "Slot increment"),
+    bitfield("mmsi2",     30, 'unsigned', 0, "Interrogated MMSI 2"),
+    bitfield("offset2",   12, 'unsigned', 0, "Second slot offset"),
+    bitfield("increment2",10, 'unsigned', 0, "Second slot increment"),
     spare(2),
     )
 
diff --git a/test/sample.aivdm b/test/sample.aivdm
index 0c3c42df..a3f72fd5 100644
--- a/test/sample.aivdm
+++ b/test/sample.aivdm
@@ -501,6 +501,8 @@
 # Type 22:
 # From AISHub.  Broadcast case: we won't count this as a full test by
 # itself because the bit layout of the addressed case is different.
+# (The addressed form seems to be rare or nonexistent in the wild; none
+# showed up in a three-hour sample from AISHub, while many broadcasts did.)
 # Verified only by the fact that the Python and C decoders get consistent
 # results, we haven't actually seen an independent dump of these fields. 
 # (The noaadata 0.42 dumper for this type doesn't seem to work.)
@@ -521,6 +523,23 @@
 #        Channel A Band           : 0
 #        Zone size                : 4
 #
+# Type 23:
+# From AISHub. Only a regression test to check that the C and Python decoders
+# do the same thing, not yet checked against other decoders.
+!AIVDM,1,1,,B,G02:Kn01R`sn@291nj600000900,2*12
+#        Message Type             : 23
+#        Repeat Indicator         : 0
+#        MMSI                     : 2268120
+#        NE Longitude             : 1578
+#        NE Latitude              : 30642
+#        SW Longitude             : 1096
+#        SW Latitude              : 30408
+#        Station Type             : 6
+#        Ship Type                : 0
+#        Tx/Rx mode               : 0
+#        Reporting interval       : 9
+#        Quiet time               : 0
+#
 # Type 24:
 # One pair of type A and Type B messages. Note, these have Coast Guard 
 # extended fields after them.
diff --git a/test/sample.aivdm.chk b/test/sample.aivdm.chk
index 81ad1ee9..91a7f6b7 100644
--- a/test/sample.aivdm.chk
+++ b/test/sample.aivdm.chk
@@ -33,4 +33,5 @@
 20,0,003160097,47,1,7,250,2250,1,7,1125,856,5,7,1125,0,0,0,0

 21,0,123456789,20,CHINA ROSE MURPHY EXPRESS ALERT,0,-73619155,28752371,5,5,5,5,1,50,165,0x0,0,0

 22,0,003160048,2087,2088,0,0,-44100,27330,-48100,25400,0,0,0,4

+23,0,002268120,1578,30642,1096,30408,6,0,2,9,0

 24,2,338085242,CAPTAIN`S PARADISE,54,ACR1234,WDD7883,8,3,2,1