binman: Add tests for etype encrypted

Add tests to reach 100% code coverage for the added etype encrypted.

Signed-off-by: Christian Taedcke <christian.taedcke@weidmueller.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/test/305_encrypted_key_file.dts b/tools/binman/test/305_encrypted_key_file.dts
new file mode 100644
index 0000000..efd7ee5
--- /dev/null
+++ b/tools/binman/test/305_encrypted_key_file.dts
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		fit {
+			description = "test desc";
+
+			images {
+				u-boot {
+					encrypted {
+						algo = "algo-name";
+						iv-filename = "encrypted-file.iv";
+						key-filename = "encrypted-file.key";
+					};
+				};
+			};
+		};
+	};
+};