watchmedo.py

import subprocess
import time
import os

from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler


class WatchMeDo(FileSystemEventHandler):
    """
    Launch pytest command, based on current updated file.
    
    This script assume that a directory 'tests' exists, 
    on root at the module directory.
    Also, tests files must have the same name and directories as
    tested files.
    """

    def process(self, event):
        if not event.is_directory:
            if '.py' in event._src_path:
                try:
                    real_path = self.get_real_path(event._src_path)

                except Exception as e:
                    print(e)
                    return

                subprocess.run(['pytest', real_path])

    def on_modified(self, event):
        self.process(event)

    def on_created(self, event):
        self.process(event)

    def get_real_path(self, src_path):
        real_path = os.path.realpath(src_path)
        base_file = os.path.basename(real_path)

        if not base_file.startswith('test_'):
            path = os.path.abspath(os.path.dirname(src_path))
            dirs = path.strip(os.environ.get('PROJECT_PATH')).split('/')
            root = dirs.pop(0)
            new_path = os.path.join(
                root, 'tests', '/'.join(dirs), 'test_%s' % base_file
            )

            new_path = os.path.join(path, 'test_%s' % base_file)

            if os.path.isfile(new_path):
                return new_path

            else:
                raise FileNotFoundError('File not found %s' % new_path)

        return real_path


if __name__ == "__main__":
    event_handler = WatchMeDo()
    observer = Observer()
    observer.schedule(event_handler, path='.', recursive=True)
    observer.start()

    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()