Add ShapeTests for Processing4 core module (#1462)

* Add ShapeTests for Processing4

* Rename ShapeTests to PGraphicsTests, move to core package, merge tests

Author: aakritithecoder

core/test/processing/core/PGraphicsTests.java

@@ -0,0 +1,19 @@
+package processing.core;
+
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import processing.core.PGraphics;
+
+public class PGraphicsTests {
+
+    @Test
+    public void testCanvasSizeAfterSetSize() {
+        // Create a PGraphics object and set its size
+        PGraphics pg = new PGraphics();
+        pg.setSize(200, 150);
+
+        // Assert that both width and height are correctly initialized
+        assertEquals(200, pg.width);
+        assertEquals(150, pg.height);
+    }
+}