test/alloc: add zpos-2x-reverse

test/meson.build

@@ -44,6 +44,7 @@ tests = {
 		'composition-3x-fail',
 		'composition-3x-partial',
 		'composition-3x-force',
+		'zpos-2x-reverse',
 	],
 	'dynamic': [
 		'same',

test/test_alloc.c

@@ -464,6 +464,26 @@ static struct test_case tests[] = {
 			},
 		},
 	},
+	{
+		.name = "zpos-2x-reverse",
+		/* Layer on top comes first */
+		.layers = {
+			{
+				.width = 100,
+				.height = 100,
+				.zpos = 2,
+				.compat = { PRIMARY_PLANE, OVERLAY_PLANE },
+				.result = OVERLAY_PLANE,
+			},
+			{
+				.width = 1920,
+				.height = 1080,
+				.zpos = 1,
+				.compat = { PRIMARY_PLANE, OVERLAY_PLANE },
+				.result = PRIMARY_PLANE,
+			},
+		},
+	},
 	{
 		.name = "composition-3x",
 		.layers = {