Fix blockers reported by SonarCloud

Author: SvenWoltmann

src/main/java/eu/happycoders/sort/method/bubblesort/BubbleSortParallel.java

@@ -2,6 +2,7 @@
 
 import eu.happycoders.sort.method.Counters;
 import eu.happycoders.sort.method.SortAlgorithm;
+import eu.happycoders.sort.utils.NotImplementedException;
 import java.util.concurrent.Phaser;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -97,6 +98,6 @@ private int[] partition(int[] elements) {
 
   @Override
   public void sort(int[] elements, Counters counters) {
-    // Not implemented
+    throw new NotImplementedException();
   }
 }

src/main/java/eu/happycoders/sort/method/heapsort/BottomUpHeapsortSlowComparisons.java

@@ -1,6 +1,7 @@
 package eu.happycoders.sort.method.heapsort;
 
 import eu.happycoders.sort.method.Counters;
+import eu.happycoders.sort.utils.NotImplementedException;
 
 public class BottomUpHeapsortSlowComparisons extends BottomUpHeapsort {
 
@@ -41,7 +42,7 @@ int findTargetNodeBottomUp(int[] heap, int rootPos, int leafPos) {
 
   @Override
   public void sort(int[] elements, Counters counters) {
-    throw new Error("Not implemented");
+    throw new NotImplementedException();
   }
 
   private void slowDown() {

src/main/java/eu/happycoders/sort/method/heapsort/HeapsortSlowComparisons.java

@@ -2,6 +2,7 @@
 
 import eu.happycoders.sort.method.Counters;
 import eu.happycoders.sort.utils.ArrayUtils;
+import eu.happycoders.sort.utils.NotImplementedException;
 
 public class HeapsortSlowComparisons extends Heapsort {
 
@@ -48,7 +49,7 @@ void heapify(int[] heap, int length, int parentPos) {
 
   @Override
   public void sort(int[] elements, Counters counters) {
-    throw new Error("Not implemented");
+    throw new NotImplementedException();
   }
 
   private void slowDown() {

src/main/java/eu/happycoders/sort/utils/NotImplementedException.java

@@ -0,0 +1,8 @@
+package eu.happycoders.sort.utils;
+
+/**
+ * An exception to be thrown from a not implemented method.
+ *
+ * @author <a href="[email protected]">Sven Woltmann</a>
+ */
+public class NotImplementedException extends RuntimeException {}

src/test/java/eu/happycoders/sort/method/countingsort/CountingSortTest.java

@@ -5,6 +5,7 @@
 import eu.happycoders.sort.utils.ArrayUtils;
 import org.junit.jupiter.api.RepeatedTest;
 
+@SuppressWarnings("java:S2699") // The assertions are in the sortAndTestIfSorted() method
 public class CountingSortTest extends SortTest {
 
   @RepeatedTest(100)