Add tests for buySellOrderMatch() method

src/OrderMatchingTest.java

+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class OrderMatchingTest {
+
+	@Test
+	void buySellOrderMatchTest() {
+		Customer c1 = new Customer("c1");
+		Customer c2 = new Customer("c2");
+		Stock appleStock = new Stock("apple");
+		Stock googleStock = new Stock("google");
+		
+		OrderMatching orderMatching = new OrderMatching();
+		
+		BuyOrder b1 = new BuyOrder(1, c1, googleStock, 100, 300);
+		BuyOrder b2 = new BuyOrder(2, c2, googleStock, 300, 200);
+		BuyOrder b3 = new BuyOrder(5, c1, googleStock, 300, 200);
+		SellOrder s1 = new SellOrder(3, c2, googleStock, 200, 200);
+		SellOrder s2 = new SellOrder(4, c2, appleStock, 200, 200);
+		
+		assertTrue(orderMatching.buySellOrderMatch(b1, s1));
+		assertFalse(orderMatching.buySellOrderMatch(b1, s2));
+		assertFalse(orderMatching.buySellOrderMatch(b1, s2));
+		assertFalse(orderMatching.buySellOrderMatch(b2, s1));
+		assertTrue(orderMatching.buySellOrderMatch(b3, s1));
+	}
+
+}