added sketch overlay tests

d2renderers/d2sketch/sketch_test.go

@@ -275,6 +275,26 @@ shipments.order_id <-> orders.id`,
   +getJobs(): "Job[]"
   +setTimeout(seconds int)
 }
+`,
+		},
+		{
+			name: "bright_overlay",
+			script: `a.style.fill = "#fff"
+`,
+		},
+		{
+			name: "normal_overlay",
+			script: `a.style.fill = "#ccc"
+`,
+		},
+		{
+			name: "dark_overlay",
+			script: `a.style.fill = "#555"
+`,
+		},
+		{
+			name: "darker_overlay",
+			script: `a.style.fill = "#000"
 `,
 		},
 	}