tests: Add stacked overlay tests on fdtoverlay

Add a stacked overlay unit test, piggybacking on fdtoverlay.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

tests/run_tests.sh

@@ -791,6 +791,21 @@ fdtoverlay_tests() {
 
     # test that the new property is installed
     run_fdtoverlay_test foobar "/test-node" "test-str-property" "-ts" ${basedtb} ${targetdtb} ${overlaydtb}
+
+    stacked_base=stacked_overlay_base.dts
+    stacked_basedtb=stacked_overlay_base.fdtoverlay.test.dtb
+    stacked_bar=stacked_overlay_bar.dts
+    stacked_bardtb=stacked_overlay_bar.fdtoverlay.test.dtb
+    stacked_baz=stacked_overlay_baz.dts
+    stacked_bazdtb=stacked_overlay_baz.fdtoverlay.test.dtb
+    stacked_targetdtb=stacked_overlay_target.fdtoverlay.test.dtb
+
+    run_dtc_test -@ -I dts -O dtb -o $stacked_basedtb $stacked_base
+    run_dtc_test -@ -I dts -O dtb -o $stacked_bardtb $stacked_bar
+    run_dtc_test -@ -I dts -O dtb -o $stacked_bazdtb $stacked_baz
+
+    # test that baz correctly inserted the property
+    run_fdtoverlay_test baz "/foonode/barnode/baznode" "baz-property" "-ts" ${stacked_basedtb} ${stacked_targetdtb} ${stacked_bardtb} ${stacked_bazdtb}
 }
 
 pylibfdt_tests () {

tests/stacked_overlay_bar.dts

@@ -0,0 +1,13 @@
+/dts-v1/;
+/plugin/;
+/ {
+	fragment@1 {
+		target = <&foo>;
+		__overlay__ {
+			overlay-1-property;
+			bar: barnode {
+				bar-property = "bar";
+			};
+		};
+	};
+};

tests/stacked_overlay_base.dts

@@ -0,0 +1,6 @@
+/dts-v1/;
+/ {
+	foo: foonode {
+		foo-property = "foo";
+	};
+};

tests/stacked_overlay_baz.dts

@@ -0,0 +1,13 @@
+/dts-v1/;
+/plugin/;
+/ {
+	fragment@1 {
+		target = <&bar>;
+		__overlay__ {
+			overlay-2-property;
+			baz: baznode {
+				baz-property = "baz";
+			};
+		};
+	};
+};