Use --support-templates in a test

conftest.py

@@ -120,6 +120,7 @@ def __init__(self, test_file: str, keep_temporaries: bool, node_name: str):
             search_dir = search_dir.parent
         self.root_dir = search_dir
         self.templates_dir = self.test_dir / pathlib.Path("templates")
+        self.support_templates_dir = self.test_dir / pathlib.Path("support")
         self.dsdl_dir = self.test_dir / pathlib.Path("dsdl")
         self.lang_src_dir = self.root_dir / pathlib.Path("src") / pathlib.Path("nunavut") / pathlib.Path("lang")
 

test/gentest_nnvg/support/serialization.j2

@@ -0,0 +1 @@
+{}

test/gentest_nnvg/test_nnvg.py

@@ -610,3 +610,22 @@ def test_list_configuration(gen_paths: typing.Any, run_nnvg: typing.Callable) ->
     )
     assert len(parsed_config[default_target_section_name]) > 0
     print(yaml.dump(parsed_config))
+
+def test_support_templates_dir(gen_paths: typing.Any, run_nnvg: typing.Callable) -> None:
+    """
+    Use the --support-templates option to find templates for support generation
+    """
+    nnvg_args = [
+        "--templates",
+        gen_paths.templates_dir.as_posix(),
+        "--support-templates",
+        gen_paths.support_templates_dir.as_posix(),
+        "-O",
+        gen_paths.out_dir.as_posix(),
+        "-I",
+        (gen_paths.dsdl_dir / pathlib.Path("scotec")).as_posix(),
+        "--list-inputs",
+        (gen_paths.dsdl_dir / pathlib.Path("uavcan")).as_posix(),
+    ]
+
+    run_nnvg(gen_paths, nnvg_args).stdout.decode("utf-8").split(";")