Validate only submitted Project Euler solution (#3977)

* Update validate solution script to fetch only submitted solution
* Update workflow file with the updated PE script
* Fix: do not fetch `validate_solutions.py` script
* Update script to use the requests package for API calls
* Fix: install requests module
* Pytest ignore scripts/ directory

scripts/validate_solutions.py

@@ -1,11 +1,13 @@
 #!/usr/bin/env python3
 import importlib.util
 import json
+import os
 import pathlib
 from types import ModuleType
 from typing import Dict, List
 
 import pytest
+import requests
 
 PROJECT_EULER_DIR_PATH = pathlib.Path.cwd().joinpath("project_euler")
 PROJECT_EULER_ANSWERS_PATH = pathlib.Path.cwd().joinpath(
@@ -24,7 +26,7 @@ def convert_path_to_module(file_path: pathlib.Path) -> ModuleType:
     return module
 
 
-def collect_solution_file_paths() -> List[pathlib.Path]:
+def all_solution_file_paths() -> List[pathlib.Path]:
     """Collects all the solution file path in the Project Euler directory"""
     solution_file_paths = []
     for problem_dir_path in PROJECT_EULER_DIR_PATH.iterdir():
@@ -37,12 +39,51 @@ def collect_solution_file_paths() -> List[pathlib.Path]:
     return solution_file_paths
 
 
+def get_files_url() -> str:
+    """Return the pull request number which triggered this action."""
+    with open(os.environ["GITHUB_EVENT_PATH"]) as file:
+        event = json.load(file)
+    return event["pull_request"]["url"] + "/files"
+
+
+def added_solution_file_path() -> List[pathlib.Path]:
+    """Collects only the solution file path which got added in the current
+    pull request.
+
+    This will only be triggered if the script is ran from GitHub Actions.
+    """
+    solution_file_paths = []
+    headers = {
+        "Accept": "application/vnd.github.v3+json",
+        "Authorization": "token " + os.environ["GITHUB_TOKEN"],
+    }
+    files = requests.get(get_files_url(), headers=headers).json()
+    for file in files:
+        filepath = pathlib.Path.cwd().joinpath(file["filename"])
+        if (
+            filepath.suffix != ".py"
+            or filepath.name.startswith(("_", "test"))
+            or not filepath.name.startswith("sol")
+        ):
+            continue
+        solution_file_paths.append(filepath)
+    return solution_file_paths
+
+
+def collect_solution_file_paths() -> List[pathlib.Path]:
+    if os.environ.get("CI") and os.environ.get("GITHUB_EVENT_NAME") == "pull_request":
+        # Return only if there are any, otherwise default to all solutions
+        if filepaths := added_solution_file_path():
+            return filepaths
+    return all_solution_file_paths()
+
+
 @pytest.mark.parametrize(
     "solution_path",
     collect_solution_file_paths(),
     ids=lambda path: f"{path.parent.name}/{path.name}",
 )
-def test_project_euler(solution_path: pathlib.Path):
+def test_project_euler(solution_path: pathlib.Path) -> None:
     """Testing for all Project Euler solutions"""
     # problem_[extract this part] and pad it with zeroes for width 3
     problem_number: str = solution_path.parent.name[8:].zfill(3)