Add tests for findMax (#3067)

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

@@ -0,0 +1,12 @@
+package com.thealgorithms.maths;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class FindMaxTest {
+    
+    @Test
+    public void testFindMaxValue(){
+        assertEquals(10, FindMax.findMax(new int[] {1,2,3,4,5,6,7,8,9,10}));
+    }
+}