twister: automatically add module board roots

Twister does not handle out-of-tree boards automatically. Modules like
e.g. example-application that define their own board root folder, are
required to inform twister via `--board-root`. In contrast, west is able
to to this automatically. This patch makes twister a bit smarter by
automatically filling the board root list with module paths as well.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

Author: gmarull

scripts/pylib/twister/twisterlib/environment.py

@@ -26,6 +26,10 @@
 if not ZEPHYR_BASE:
     sys.exit("$ZEPHYR_BASE environment variable undefined")
 
+sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts/"))
+
+import zephyr_module
+
 # Use this for internal comparisons; that's what canonicalization is
 # for. Don't use it when invoking other components of the build system
 # to avoid confusing and hard to trace inconsistencies in error messages
@@ -228,6 +232,12 @@ def add_parse_arguments(parser = None):
     board_root_list = ["%s/boards" % ZEPHYR_BASE,
                        "%s/scripts/pylib/twister/boards" % ZEPHYR_BASE]
 
+    modules = zephyr_module.parse_modules(ZEPHYR_BASE)
+    for module in modules:
+        board_root = module.meta.get("build", {}).get("settings", {}).get("board_root")
+        if board_root:
+            board_root_list.append(os.path.join(module.project, board_root, "boards"))
+
     parser.add_argument(
         "-A", "--board-root", action="append", default=board_root_list,
         help="""Directory to search for board configuration files. All .yaml