A simple context manager that enabes to change time.time() to whatever you need (future or past) in your unit tests.

mock_time.py

import contextlib
import time

@contextlib.contextmanager
def mock_time(timestamp):
    """A simple context manager for mocking time.time() useful for traveling
    immediately in the future or in the past in unit tests.

      >>> t0 = time.time()
      >>> with mock_time(t0 + 5.0):
      >>>   t1 = time.time()
      >>> t1 - t0
      5.0
    """
    def my_time():
        return timestamp
    sv_time = time.time
    time.time = my_time
    try:
        yield timestamp
    finally:
        time.time = sv_time