fix(verifier): require positive bounds for swipe candidates

A zero-bounds element centers at (0,0); a downward swipe from the
top-left corner is the system gesture that pulls down the notification
shade, dragging the fuzzer out of the app. Swipes now require positive
bounds like every other verb.

internal/verifier/worker_test.go

@@ -0,0 +1,23 @@
+package verifier
+
+import (
+	"testing"
+
+	"github.com/priyanshujain/sanderling/internal/hierarchy"
+)
+
+// TestVerbAcceptsSwipeRequiresPositiveBounds locks the fix for the notification
+// shade: a zero-bounds element centers at (0,0), and a downward swipe from the
+// top-left corner is the system gesture that pulls the shade over the app. The
+// swipe verb must reject zero-bounds nodes like every other verb does.
+func TestVerbAcceptsSwipeRequiresPositiveBounds(t *testing.T) {
+	zeroBounds := &hierarchy.Element{Bounds: hierarchy.Bounds{}}
+	if verbAccepts("swipes", zeroBounds) {
+		t.Error("swipes must reject a zero-bounds element (it centers at (0,0) and pulls the notification shade)")
+	}
+
+	realBounds := &hierarchy.Element{Bounds: hierarchy.Bounds{Left: 100, Top: 400, Right: 980, Bottom: 600}}
+	if !verbAccepts("swipes", realBounds) {
+		t.Error("swipes must accept an element with positive bounds")
+	}
+}