of: overlay: unittest: Add test for unresolved symbol

Add a test to exercise the error paths when trying to apply an overlay
with an unresolved symbol and cleaning up the resulting partial state.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/580394587976975770c84411896fce9fbbcf25fa.1690533838.git.geert+renesas@glider.beSigned-off-by: Rob Herring <robh@kernel.org>

drivers/of/unittest-data/Makefile

@@ -33,7 +33,8 @@ obj-$(CONFIG_OF_OVERLAY) += overlay.dtbo.o \
 			    overlay_gpio_03.dtbo.o \
 			    overlay_gpio_04a.dtbo.o \
 			    overlay_gpio_04b.dtbo.o \
-			    overlay_pci_node.dtbo.o
+			    overlay_pci_node.dtbo.o \
+			    overlay_bad_unresolved.dtbo.o
 
 # enable creation of __symbols__ node
 DTC_FLAGS_overlay += -@

drivers/of/unittest-data/overlay_bad_unresolved.dtso

+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+/plugin/;
+
+&this_label_does_not_exist {
+	status = "ok";
+};

drivers/of/unittest.c

@@ -3336,6 +3336,7 @@ OVERLAY_INFO_EXTERN(overlay_bad_add_dup_node);
 OVERLAY_INFO_EXTERN(overlay_bad_add_dup_prop);
 OVERLAY_INFO_EXTERN(overlay_bad_phandle);
 OVERLAY_INFO_EXTERN(overlay_bad_symbol);
+OVERLAY_INFO_EXTERN(overlay_bad_unresolved);
 
 /* entries found by name */
 static struct overlay_info overlays[] = {
@@ -3372,6 +3373,7 @@ static struct overlay_info overlays[] = {
 	OVERLAY_INFO(overlay_bad_add_dup_prop, -EINVAL, -ENODEV),
 	OVERLAY_INFO(overlay_bad_phandle, -EINVAL, 0),
 	OVERLAY_INFO(overlay_bad_symbol, -EINVAL, -ENODEV),
+	OVERLAY_INFO(overlay_bad_unresolved, -EINVAL, 0),
 	/* end marker */
 	{ }
 };
@@ -3776,6 +3778,21 @@ static __init void of_unittest_overlay_high_level(void)
 	EXPECT_END(KERN_ERR,
 		   "OF: changeset: apply failed: REMOVE_PROPERTY /testcase-data-2/substation@100/hvac-medium-2:name");
 
+	/* ---  overlay_bad_unresolved  --- */
+
+	EXPECT_BEGIN(KERN_ERR,
+		     "OF: resolver: node label 'this_label_does_not_exist' not found in live devicetree symbols table");
+	EXPECT_BEGIN(KERN_ERR,
+		     "OF: resolver: overlay phandle fixup failed: -22");
+
+	unittest(overlay_data_apply("overlay_bad_unresolved", NULL),
+		 "Adding overlay 'overlay_bad_unresolved' failed\n");
+
+	EXPECT_END(KERN_ERR,
+		   "OF: resolver: overlay phandle fixup failed: -22");
+	EXPECT_END(KERN_ERR,
+		   "OF: resolver: node label 'this_label_does_not_exist' not found in live devicetree symbols table");
+
 	return;
 
 err_unlock: