Add tests for isPerfectSquare (TheAlgorithms#3131)

Author: Anhduc2k2

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

@@ -0,0 +1,37 @@
+package com.thealgorithms.maths;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+
+public class PerfectSquareTest{
+	
+	@Test
+	public void TestPerfectSquareifiscorrect(){
+		//Valid Partition
+		int number = 9;
+		
+		boolean result = PerfectSquare.isPerfectSquare(number);
+		
+		assertTrue(result);
+	}
+	
+	@Test
+	public void TestPerfectSquareifisnotcorrect(){
+		//Invalid Partition 1
+		int number = 3;
+		
+		boolean result = PerfectSquare.isPerfectSquare(number);
+		
+		assertFalse(result);
+	}
+	@Test
+	public void TestPerfectSquareifisNegativeNumber(){
+		//Invalid Partition 2
+		int number = -10;
+
+		boolean result = PerfectSquare.isPerfectSquare(number);
+
+		assertFalse(result);
+	}
+}