Add more tests to RotateLinkedList. Adjust regex for ValidNumber solution

Author: andrei-punko

src/main/java/by/andd3dfx/numeric/ValidNumber.java

@@ -32,6 +32,6 @@
 public class ValidNumber {
 
     public static boolean isNumber(String s) {
-        return s.matches("(\\+|-)?([0-9]+\\.?([0-9]+)?|\\.[0-9]+)((e|E)(\\+|-)?[0-9]+)?");
+        return s.matches("(\\+|-)?(\\d+\\.?(\\d+)?|\\.\\d+)((e|E)(\\+|-)?\\d+)?");
     }
 }

src/test/java/by/andd3dfx/collections/RotateLinkedListTest.java

@@ -27,13 +27,27 @@ public void testRotateRight_whenJustShiftNeeded2() {
         checkLinkedListContent(result2, new int[]{2, 1});
     }
 
+    @Test
+    public void testRotateRight_whenJustBackwardShiftNeeded() {
+        var result = rotateRight(buildLinkedList(new int[]{1, 2, 3, 4, 5}), -2);
+
+        checkLinkedListContent(result, new int[]{3, 4, 5, 1, 2});
+    }
+
     @Test
     public void testRotateRight_whenShiftGreaterThanArraySize() {
         var result = rotateRight(buildLinkedList(new int[]{0, 1, 2}), 4);
 
         checkLinkedListContent(result, new int[]{2, 0, 1});
     }
 
+    @Test
+    public void testRotateRight_whenBackwardShiftGreaterThanArraySize() {
+        var result = rotateRight(buildLinkedList(new int[]{0, 1, 2}), -4);
+
+        checkLinkedListContent(result, new int[]{1, 2, 0});
+    }
+
     @Test
     public void testRotateRight_whenShiftGreaterThanArraySizeButEqualsToIntAmountOfSizes() {
         var result = rotateRight(buildLinkedList(new int[]{0, 1, 2}), 6);