Handle scenario where message fragments never arrive (#56)

Co-authored-by: Ian Griffiths <[email protected]>
Co-authored-by: Carmel Eve <[email protected]>

Solutions/Ais.Net.Specs/Ais/Net/Specs/NmeaAisMessageStreamProcessorBindings.cs

@@ -98,6 +98,16 @@ public void ThenTheMessageErrorReportShouldIncludeAnExceptionReportingThatItHasR
             Assert.AreEqual(expectedStart, e.Message.Substring(0, expectedStart.Length));
         }
 
+        [Then("the message error report (.*) should include an exception reporting that it received an incomplete set of fragments for a message")]
+        public void ThenTheMessageErrorReportShouldIncludeAnExceptionReportingThatItReceivedAnIncompleteSetOfFragmentsForAMessage(int errorCallNumber)
+        {
+            NmeaAisMessageStreamProcessorBindings.ErrorReport call = this.OnErrorCalls[errorCallNumber];
+            Assert.IsInstanceOf<ArgumentException>(call.Error);
+
+            var e = (ArgumentException)call.Error;
+            Assert.AreEqual("Received incomplete fragmented message.", e.Message);
+        }
+
         [Then("the message error report (.*) should include the line number (.*)")]
         public void ThenTheMessageErrorReportShouldIncludeTheLineNumber(int errorCallNumber, int lineNumber)
         {

Solutions/Ais.Net.Specs/Ais/Net/Specs/NmeaLineToAisStreamAdapterSpecs.feature

@@ -88,6 +88,8 @@ Scenario: Interleaved multi-fragment messages
     And in ais message 1 the timestamp from the first NMEA line should be 1567686150
 
 Scenario: Interleaved single and multi-fragment messages
+	# This test interleaves more extensively than we ever see in reality, so we have to extend our reassembly window
+	Given I have configured a MaximumUnmatchedFragmentAge of 10
 	# ais.kystverket.no
 	When the line to message adapter receives '\s:42,c:1567684904*38\!AIVDM,1,1,,B,33m9UtPP@50wwE:VJW6LS67H01<@,0*3C'
 	# ais.kystverket.no
@@ -157,6 +159,8 @@ Scenario: Interleaved single and multi-fragment messages
     And in ais message 9 the timestamp from the first NMEA line should be 1567693618
 
 Scenario: Progress reports
+	# This test interleaves more extensively than we ever see in reality, so we have to extend our reassembly window
+	Given I have configured a MaximumUnmatchedFragmentAge of 10
 	# ais.kystverket.no
 	When the line to message adapter receives '\s:42,c:1567684904*38\!AIVDM,1,1,,B,33m9UtPP@50wwE:VJW6LS67H01<@,0*3C'
 	# ais.kystverket.no
@@ -238,6 +242,31 @@ Scenario: Line stream parser passes the same sentence of a two-part message twic
 	And the message error report 0 should include an exception reporting that it has received two message fragments with the same group id and position
 	And the message error report 0 should include the line number 2
 
+Scenario: Two-fragment message fragments received too many sentences in the middle
+	Given I have configured a MaximumUnmatchedFragmentAge of 1
+	# ais.kystverket.no
+	When the line to message adapter receives '\g:1-2-8055,s:99,c:1567685556*4E\!AIVDM,2,1,6,B,53oGfN42=WRDhlHn221<4i@Dr22222222222220`1@O6640Ht50Skp4mR`4l,0*72'
+	# ais.kystverket.no
+	And the line to message adapter receives '\s:42,c:1567684904*38\!AIVDM,1,1,,B,33m9UtPP@50wwE:VJW6LS67H01<@,0*3C'
+	# ais.kystverket.no
+	And the line to message adapter receives '\s:3,c:1567692251*01\!AIVDM,1,1,,A,13m9WS001d0K==pR=D?HB6WD0pJV,0*54,0*63'
+	# ais.kystverket.no
+	And the line to message adapter receives '\g:2-2-8055*55\!AIVDM,2,2,6,B,j`888888880,2*2B'
+	Then INmeaAisMessageStreamProcessor.OnNext should have been called 2 times
+	Then INmeaAisMessageStreamProcessor.OnError should have been called 1 time
+	# ais.kystverket.no
+    And in ais message 0 the payload should be '33m9UtPP@50wwE:VJW6LS67H01<@' with padding of 0
+    And in ais message 0 the source from the first NMEA line should be 42
+    And in ais message 0 the timestamp from the first NMEA line should be 1567684904
+	# ais.kystverket.no
+    And in ais message 1 the payload should be '13m9WS001d0K==pR=D?HB6WD0pJV' with padding of 0
+    And in ais message 1 the source from the first NMEA line should be 3
+    And in ais message 1 the timestamp from the first NMEA line should be 1567692251
+	# ais.kystverket.no
+	And the message error report 0 should include the problematic line '\g:1-2-8055,s:99,c:1567685556*4E\!AIVDM,2,1,6,B,53oGfN42=WRDhlHn221<4i@Dr22222222222220`1@O6640Ht50Skp4mR`4l,0*72'
+	And the message error report 0 should include an exception reporting that it received an incomplete set of fragments for a message
+	And the message error report 0 should include the line number 1
+
 
 
 # TODO: