Add Message2Test.java with an initial test case.

java/src/test/java/com/aisparser/Message2Test.java

@@ -0,0 +1,47 @@
+package com.aisparser;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link Message2}. */
+@RunWith(JUnit4.class)
+public class Message2Test {
+
+    // Verifies decode of Msg 2 for a ship in a turn.
+    @Test
+    public void testParse() {
+        Message2 msg = new Message2();
+
+        try {
+            Vdm vdm_message = new Vdm();
+            int result = vdm_message.add("!AIVDM,1,1,,B,284;UGTdP4301>3L;B@Wk3TnU@A1,0*7C\r\n");
+            assertEquals("vdm add failed", 0, result);
+            msg.parse(vdm_message.sixbit());
+        } catch (Exception e) {
+            fail(e.getMessage());
+        }
+
+        assertEquals("msgid", 2, msg.msgid());
+        assertEquals("repeat", 0, msg.repeat());
+        assertEquals("userid", 541255006, msg.userid());
+        assertEquals("nav_status", 4, msg.nav_status());
+        assertEquals("rot", 178, msg.rot());
+        assertEquals("sog", 4, msg.sog());
+        assertEquals("pos_acc", 0, msg.pos_acc());
+        assertEquals("longitude", 25168321, msg.longitude()); // 41.947201666666665
+        assertEquals("latitude", -37563838, msg.latitude()); // -62.606396666666669
+        assertEquals("cog", 1996, msg.cog());
+        assertEquals("true_heading", 114, msg.true_heading());
+        assertEquals("utc_sec", 27, msg.utc_sec());
+        assertEquals("regional", 4, msg.regional());
+        assertEquals("spare", 1, msg.spare());
+        assertEquals("raim", 0, msg.raim());
+        assertEquals("sync_state", 2, msg.sync_state());
+        assertEquals("slot_timeout", 4, msg.slot_timeout());
+        assertEquals("sub_message", 1089, msg.sub_message());
+    }
+}