feat: update structure

cs2030s/labs/PE2/plab0124/Test4.java

@@ -0,0 +1,20 @@
+import java.util.stream.Collectors;
+import java.util.List;
+
+class Test4 {
+  public static void main(String[] args) {
+    CS2030STest i = new CS2030STest();
+
+    i.expectReturn("Streaming.evenTriangular(5).count()",
+        () -> Streaming.evenTriangular(5).count(),
+        5L);
+
+    i.expectReturn("Streaming.evenTriangular(5).collect(Collectors.toList())",
+        () -> Streaming.evenTriangular(5).collect(Collectors.toList()),
+        List.of(6,10,28,36,66));
+
+    i.expectReturn("Streaming.evenTriangular(10).collect(Collectors.toList())",
+        () -> Streaming.evenTriangular(10).collect(Collectors.toList()),
+        List.of(6,10,28,36,66,78,120,136,190,210));
+  }
+}