Correctly derail

fuzz8_input.txt

@@ -0,0 +1,10 @@
+add track (0,0) -> (0,14)
+create engine diesel T3 Sabine 1 false true
+add train 1 T3-Sabine
+put train 1 at (0,0) in direction 0,-1
+step -20
+create coach passenger 1 true false
+add train 1 W1
+put train 1 at (0,0) in direction 0,-1
+step -20
+exit

fuzz8_output.txt

@@ -0,0 +1,9 @@
+1
+T3-Sabine
+diesel engine T3-Sabine added to train 1
+OK
+Crash of train 1
+1
+passenger coach W1 added to train 1
+OK
+Crash of train 1

src/edu/kit/informatik/MainTest.java

@@ -68,6 +68,11 @@ class MainTest {
         cmpInOut("fuzz7_input.txt", "fuzz7_output.txt");
     }
 
+    @Test
+    void fuzz8() throws IOException {
+        cmpInOut("fuzz8_input.txt", "fuzz8_output.txt");
+    }
+
     private void cmpInOut(String in, String out) throws IOException {
         System.setIn(new ByteArrayInputStream(readFile(in)));
         ByteArrayOutputStream output = new ByteArrayOutputStream();

src/edu/kit/informatik/model/Train.java

@@ -301,8 +301,11 @@ public final class Train {
         } else if (getLength() == 1) {
             // we evidently just moved into another rail
             Rail[] nextTouchingRails = railNetwork.findTouchingRails(nextPosition);
-            Rail[] alreadyTouchingRails = railNetwork.findTouchingRails(position.get(position.size() - 1));
+            Rail[] alreadyTouchingRails = railNetwork.findTouchingRails(secondToLastPosition);
-            if (nextTouchingRails[0] == alreadyTouchingRails[0]) {
+            if (alreadyTouchingRails.length == 0) {
+                // we evidently just derailed, be we should still crash with trains entering our last rail
+                assert !occupiedRails.isEmpty();
+            } else if (nextTouchingRails[0] == alreadyTouchingRails[0]) {
                 occupiedRails.add(nextTouchingRails[0]);
             } else if (nextTouchingRails.length == 2) {
                 if (nextTouchingRails[1] == alreadyTouchingRails[0]) {