Add MinValueTest and remove main from MinValue (#4713)

* Update MinValue.java

* Create MinValueTest.java

* Revert "Create MinValueTest.java"

* Create MinValueTest.java

* Update MinValueTest.java

* Update MinValueTest.java

* Update MinValue.java

* Update src/test/java/com/thealgorithms/maths/MinValueTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/test/java/com/thealgorithms/maths/MinValueTest.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

* Update src/main/java/com/thealgorithms/maths/MinValue.java

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

src/main/java/com/thealgorithms/maths/MinValue.java

@@ -1,24 +1,8 @@
 package com.thealgorithms.maths;
 
-import java.util.Random;
-
-public class MinValue {
-
-    /**
-     * Driver Code
-     */
-    public static void main(String[] args) {
-        Random rand = new Random();
-
-        /* test 100 times using rand numbers */
-        for (int i = 1; i <= 100; ++i) {
-            /* generate number from -50 to 49 */
-            int a = rand.nextInt(100) - 50;
-            int b = rand.nextInt(100) - 50;
-            assert min(a, b) == Math.min(a, b);
-        }
+public final class MinValue {
+    private MinValue() {
     }
-
     /**
      * Returns the smaller of two {@code int} values. That is, the result the
      * argument closer to the value of {@link Integer#MIN_VALUE}. If the

src/test/java/com/thealgorithms/maths/MinValueTest.java

@@ -0,0 +1,14 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class MinValueTest {
+    @Test
+    public void minTest() {
+        assertEquals(-1, MinValue.min(-1, 3));
+        assertEquals(2, MinValue.min(3, 2));
+        assertEquals(5, MinValue.min(5, 5));
+    }
+}