[RFC PATCH v2 69/74] tests: fdtaddon: Add a test for addons with properties identical to existing ones

[Herve Codina]

An addon cannot modify or add a property in a existing node.

If an addon has a property with the exact same value as an existing one,
applying the addon doesn't lead to a property modification.

Indeed, because both properties (the addon one and the existing one) are
equal, the existing one is not modified.

Add a test for this feature.

Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
---
 ...n_addon_prop_existing_ok-merged.dtb.expect | 20 +++++++++++++++
 ...dtaddon_addon_prop_existing_ok.dtba.expect | 17 +++++++++++++
 tests/fdtaddon_addon_prop_existing_ok.dtsa    | 25 +++++++++++++++++++
 tests/fdtaddon_base_prop_existing.dtb.expect  | 17 +++++++++++++
 tests/fdtaddon_base_prop_existing.dts         | 22 ++++++++++++++++
 tests/run_tests.sh                            | 12 +++++++++
 6 files changed, 113 insertions(+)
 create mode 100644 tests/fdtaddon_addon_prop_existing_ok-merged.dtb.expect
 create mode 100644 tests/fdtaddon_addon_prop_existing_ok.dtba.expect
 create mode 100644 tests/fdtaddon_addon_prop_existing_ok.dtsa
 create mode 100644 tests/fdtaddon_base_prop_existing.dtb.expect
 create mode 100644 tests/fdtaddon_base_prop_existing.dts

diff --git a/tests/fdtaddon_addon_prop_existing_ok-merged.dtb.expect b/tests/fdtaddon_addon_prop_existing_ok-merged.dtb.expect
new file mode 100644
index 00000000..a49c3f36
--- /dev/null
+++ b/tests/fdtaddon_addon_prop_existing_ok-merged.dtb.expect
@@ -0,0 +1,20 @@
+/dts-v1/;
+
+/ {
+    base-node {
+        // [FDT_EXPORT_SYM] 'base' -> phandle 0x00000001
+        compatible = "abc,base";
+        exist_bool;
+        exist_int = <0x0000007b>;
+        exist_string = "abcdef";
+        phandle = <0x00000001>;
+        sub-node {
+            sub_exist_bool;
+            sub_exist_int = <0x000001c8>;
+            sub_exist_string = "ghi";
+            addon-node {
+                prop;
+            };
+        };
+    };
+};
diff --git a/tests/fdtaddon_addon_prop_existing_ok.dtba.expect b/tests/fdtaddon_addon_prop_existing_ok.dtba.expect
new file mode 100644
index 00000000..c16c38c7
--- /dev/null
+++ b/tests/fdtaddon_addon_prop_existing_ok.dtba.expect
@@ -0,0 +1,17 @@
+/dts-v1/;
+/addon/;
+
+// [FDT_IMPORT_SYM] 'base' (abc,base)
+&base {
+    exist_bool;
+    exist_int = <0x0000007b>;
+    exist_string = "abcdef";
+    sub-node {
+        sub_exist_bool;
+        sub_exist_int = <0x000001c8>;
+        sub_exist_string = "ghi";
+        addon-node {
+            prop;
+        };
+    };
+};
diff --git a/tests/fdtaddon_addon_prop_existing_ok.dtsa b/tests/fdtaddon_addon_prop_existing_ok.dtsa
new file mode 100644
index 00000000..16e525c1
--- /dev/null
+++ b/tests/fdtaddon_addon_prop_existing_ok.dtsa
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * Copyright (C) 2026 Bootlin
+ */
+
+/dts-v1/;
+/addon/;
+
+/import/ base: "abc,base";
+
+&base {
+	exist_bool;
+	exist_int = <123>;
+	exist_string = "abcdef";
+
+	sub-node {
+		sub_exist_bool;
+		sub_exist_int = <456>;
+		sub_exist_string = "ghi";
+
+		addon-node {
+			prop;
+		};
+	};
+};
diff --git a/tests/fdtaddon_base_prop_existing.dtb.expect b/tests/fdtaddon_base_prop_existing.dtb.expect
new file mode 100644
index 00000000..2b9d3ac0
--- /dev/null
+++ b/tests/fdtaddon_base_prop_existing.dtb.expect
@@ -0,0 +1,17 @@
+/dts-v1/;
+
+/ {
+    base-node {
+        // [FDT_EXPORT_SYM] 'base' -> phandle 0x00000001
+        compatible = "abc,base";
+        exist_bool;
+        exist_int = <0x0000007b>;
+        exist_string = "abcdef";
+        phandle = <0x00000001>;
+        sub-node {
+            sub_exist_bool;
+            sub_exist_int = <0x000001c8>;
+            sub_exist_string = "ghi";
+        };
+    };
+};
diff --git a/tests/fdtaddon_base_prop_existing.dts b/tests/fdtaddon_base_prop_existing.dts
new file mode 100644
index 00000000..7b0f7102
--- /dev/null
+++ b/tests/fdtaddon_base_prop_existing.dts
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * Copyright (C) 2026 Bootlin
+ */
+
+/dts-v1/;
+
+/ {
+	base_node: base-node {
+		compatible = "abc,base";
+		exist_bool;
+		exist_int = <123>;
+		exist_string = "abcdef";
+		/export/ base: &base_node;
+
+		sub-node {
+			sub_exist_bool;
+			sub_exist_int = <456>;
+			sub_exist_string = "ghi";
+		};
+	};
+};
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 5f09bf47..0182dffc 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -1322,6 +1322,18 @@ fdtaddon_tests() {
 		run_dtc_test -I dtb -O dts -o $dt-merged2.dtb.dts $dt-merged2.dtb
 		check_dts $dt-merged2.dtb.dts
 	done
+
+	# Test addon with exact same properties as ones available in the base tree
+	run_dtc_test -I dts -O dtb -o fdtaddon_base_prop_existing.dtb "$SRCDIR/fdtaddon_base_prop_existing.dts"
+	check_dtb fdtaddon_base_prop_existing.dtb
+
+	run_dtc_test -I dts -O dtb -o fdtaddon_addon_prop_existing_ok.dtba "$SRCDIR/fdtaddon_addon_prop_existing_ok.dtsa"
+	check_dtb fdtaddon_addon_prop_existing_ok.dtba
+
+	run_fdtaddon_test -i fdtaddon_base_prop_existing.dtb -o fdtaddon_addon_prop_existing_ok-merged.dtb \
+			  -t "/base-node" fdtaddon_addon_prop_existing_ok.dtba
+	check_dtb fdtaddon_addon_prop_existing_ok-merged.dtb
+
 }
 
 pylibfdt_tests () {
-- 
2.55.0