bug: generate a valid class name when the project name starts with a digit

lean/components/util/name_extraction.py

@@ -31,4 +31,10 @@ def convert_to_class_name(file_path: Path):
     :return: returns a valid class name
     """
     from re import sub
-    return sub(f"[^a-zA-Z0-9]", "", "".join(map(_capitalize, file_path.name.split(" "))))
+    class_name = sub(f"[^a-zA-Z0-9]", "", "".join(map(_capitalize, file_path.name.split(" "))))
+
+    # An identifier cannot be empty or start with a digit
+    if class_name == "" or class_name[0].isdigit():
+        class_name = "_" + class_name
+
+    return class_name

tests/commands/test_create_project.py

@@ -157,6 +157,22 @@ def test_create_project_preserves_capitals_in_class_name() -> None:
         assert "class MyFIRSTProject(QCAlgorithm)" in file.read()
 
 
+@pytest.mark.parametrize("name,class_name", [("2024 momentum", "_2024Momentum"),
+                                             ("123", "_123")])
+def test_create_project_creates_valid_class_name_when_name_starts_with_digit(name: str, class_name: str) -> None:
+    create_fake_lean_cli_directory()
+
+    result = CliRunner().invoke(lean, ["create-project", "--language", "python", name])
+
+    assert result.exit_code == 0
+
+    with open(Path.cwd() / name / "main.py") as file:
+        content = file.read()
+
+    assert f"class {class_name}(QCAlgorithm)" in content
+    compile(content, "main.py", "exec")
+
+
 def test_create_project_aborts_when_path_invalid() -> None:
     create_fake_lean_cli_directory()