Merge pull request #138 from cryptimeleon/bugfix/vector-concatenate

Fix concatenation.

Author: this-kramer

src/main/java/org/cryptimeleon/math/structures/cartesian/Vector.java

@@ -329,7 +329,7 @@ public Vector<X> truncate(int newLength) {
     public Vector<X> concatenate(Vector<? extends X> secondPart) {
         ArrayList<X> result = new ArrayList<>(values.size() + secondPart.values.size());
         result.addAll(values);
-        result.add((X) secondPart.values);
+        result.addAll(secondPart.values);
 
         return instantiateWithSafeArray(result);
     }

src/test/java/org/cryptimeleon/math/structures/VectorTests.java

@@ -0,0 +1,23 @@
+package org.cryptimeleon.math.structures;
+
+import org.cryptimeleon.math.structures.cartesian.Vector;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class VectorTests {
+
+    /**
+     * Test that concatenation yields the correct result.
+     */
+    @Test
+    void testConcatenation() {
+        Vector<Integer> firstVector = Vector.of(0, 1, 2, 3);
+        Vector<Integer> secondVector = Vector.of(4, 5, 6);
+        Vector<Integer> concatenation = firstVector.concatenate(secondVector);
+
+        assertEquals(concatenation.length(), firstVector.length() + secondVector.length());
+        for (int i = 0; i < concatenation.length(); i++)
+            assertEquals(concatenation.get(i), i);
+    }
+}