Make it easier to locally test ci_set_matrix

Now you can e.g., `tools/ci_set_matrix.py ports/raspberrypi/mpconfigport.h`
and see what outputs would be set.

docs/shared_bindings_matrix.py

@@ -80,12 +80,11 @@ This is the same list as in the preprocess_frozen_modules script."""
 repository_urls = {}
 """Cache of repository URLs for frozen modules."""
 
+root_dir = pathlib.Path(__file__).resolve().parent.parent
+
 def get_circuitpython_root_dir():
     """ The path to the root './circuitpython' directory.
     """
-    file_path = pathlib.Path(__file__).resolve()
-    root_dir = file_path.parent.parent
-
     return root_dir
 
 def get_shared_bindings():
@@ -102,7 +101,7 @@ def get_board_mapping():
     """
     boards = {}
     for port in SUPPORTED_PORTS:
-        board_path = os.path.join("../ports", port, "boards")
+        board_path = root_dir / "ports" / port / "boards"
         for board_path in os.scandir(board_path):
             if board_path.is_dir():
                 board_files = os.listdir(board_path.path)

tools/ci_set_matrix.py

@@ -19,6 +19,13 @@ import os
 import sys
 import json
 import yaml
+import pathlib
+
+tools_dir = pathlib.Path(__file__).resolve().parent
+top_dir = tools_dir.parent
+
+sys.path.insert(0, str(tools_dir / "adabot"))
+sys.path.insert(0, str(top_dir / "docs"))
 
 import build_board_info
 from shared_bindings_matrix import get_settings_from_makefile
@@ -40,12 +47,17 @@ IGNORE = [
     "tools/ci_check_duplicate_usb_vid_pid.py",
 ]
 
-changed_files = {}
-try:
+if len(sys.argv) > 1:
+    print("Using files list on commandline")
+    changed_files = sys.argv[1:]
+else:
+    c = os.environ["CHANGED_FILES"]
+    if c == "":
+        print("CHANGED_FILES is in environment, but value is empty")
+        changed_files = []
+    else:
+        print("Using files list in CHANGED_FILES")
         changed_files = json.loads(os.environ["CHANGED_FILES"])
-except json.decoder.JSONDecodeError as exc:
-    if exc.msg != "Expecting value":
-        raise
 
 
 def set_output(name, value):
@@ -53,7 +65,7 @@ def set_output(name, value):
         with open(os.environ["GITHUB_OUTPUT"], "at") as f:
             print(f"{name}={value}", file=f)
     else:
-        print("Would set GitHub actions output {name} to '{value}'")
+        print(f"Would set GitHub actions output {name} to '{value}'")
 
 
 def set_boards_to_build(build_all):
@@ -114,7 +126,7 @@ def set_boards_to_build(build_all):
                 for board in all_board_ids:
                     if board not in board_settings:
                         board_settings[board] = get_settings_from_makefile(
-                            "../ports/" + board_to_port[board], board
+                            str(top_dir / "ports" / board_to_port[board]), board
                         )
                     settings = board_settings[board]