Run a python file as if it were the main program on the command line.

    `filename` is the path to the file to execute, it need not be a .py file.
    `args` is the argument array to present as sys.argv, including the first
    element naming the file being executed.  `package` is the name of the
    enclosing package, if any.

def run_python_file(filename, args, package=None, collector=None):
    """Run a python file as if it were the main program on the command line.

    `filename` is the path to the file to execute, it need not be a .py file.
    `args` is the argument array to present as sys.argv, including the first
    element naming the file being executed.  `package` is the name of the
    enclosing package, if any.

    """
    # Create a module to serve as __main__
    old_main_mod = sys.modules['__main__']
    main_mod = imp.new_module('__main__')
    sys.modules['__main__'] = main_mod
    main_mod.__file__ = filename
    if package:
        main_mod.__package__ = package
    main_mod.__builtins__ = sys.modules['__builtin__']

    # Set sys.argv and the first path element properly.
    old_argv = sys.argv
    old_path0 = sys.path[0]
    sys.argv = args
    if package:
        sys.path[0] = ''
    else:
        sys.path[0] = os.path.abspath(os.path.dirname(filename))

    try:
        # Open the source file.
        try:
            source_file = open(filename, 'rU')
        except IOError:
            raise NoSource("No file to run: %r" % filename)

        try:
            source = source_file.read()
        finally:
            source_file.close()

        # We have the source.  `compile` still needs the last line to be clean,
        # so make sure it is, then compile a code object from it.
        if source[-1] != '\n':
            source += '\n'
        code = compile(source, filename, "exec")

        # Execute the source file.
        try:
            exec code in main_mod.__dict__
        except SystemExit:
            # The user called sys.exit().  Just pass it along to the upper
            # layers, where it will be handled.
            raise
        except:
            # Something went wrong while executing the user code.
            # Get the exc_info, and pack them into an exception that we can
            # throw up to the outer loop.  We peel two layers off the traceback
            # so that the coverage.py code doesn't appear in the final printed
            # traceback.
            typ, err, tb = sys.exc_info()
            raise ExceptionDuringRun(typ, err, tb.tb_next.tb_next)
    finally:
        # Restore the old __main__
        sys.modules['__main__'] = old_main_mod

        # Restore the old argv and path
        sys.argv = old_argv
        sys.path[0] = old_path0