From 9191028934deb4fa8565aea26c90329feb9b79eb Mon Sep 17 00:00:00 2001
From: Arne Keller <arne.keller01@yahoo.de>
Date: Sun, 16 Feb 2020 19:42:12 +0100
Subject: [PATCH] Correctly derail

---
 fuzz8_input.txt                         | 10 ++++++++++
 fuzz8_output.txt                        |  9 +++++++++
 src/edu/kit/informatik/MainTest.java    |  5 +++++
 src/edu/kit/informatik/model/Train.java |  7 +++++--
 4 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 fuzz8_input.txt
 create mode 100644 fuzz8_output.txt

diff --git a/fuzz8_input.txt b/fuzz8_input.txt
new file mode 100644
index 0000000..87b5a09
--- /dev/null
+++ b/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
diff --git a/fuzz8_output.txt b/fuzz8_output.txt
new file mode 100644
index 0000000..153e406
--- /dev/null
+++ b/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
diff --git a/src/edu/kit/informatik/MainTest.java b/src/edu/kit/informatik/MainTest.java
index bd1c9f1..4ba2ddf 100644
--- a/src/edu/kit/informatik/MainTest.java
+++ b/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();
diff --git a/src/edu/kit/informatik/model/Train.java b/src/edu/kit/informatik/model/Train.java
index d6bbbf2..f05b838 100644
--- a/src/edu/kit/informatik/model/Train.java
+++ b/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));
-            if (nextTouchingRails[0] == alreadyTouchingRails[0]) {
+            Rail[] alreadyTouchingRails = railNetwork.findTouchingRails(secondToLastPosition);
+            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]) {