Cross platform simple worker (#1629)

* Added CrossPlatformDeathPenalty that doesn't rely on signals

* Updated `SimpleWorker`'s `death_penalty_class` to utilize `CrossPlatformDeathPenalty` to allow use on Windows machines

* Changed `CrossPlatformDeathPenalty` to `TimerDeathPenalty`

* Removed overridden `death_penalty_class` in `SimpleWorker` until feature matures

* Added section in testing.md explaining how to utilize `SimpleWorker` on Windows OS

* Replaced usage of chatting with .format for python 3.5 compatibility

* Add tests for new timeout feature

* Explicitly set defaults.CALLBACK_TIMEOUT

* Implemented cross-thread method of raising errors by using ctypes

* Finished writing tests for new TimerDeathPenalty

1 files changed, 20 insertions, 1 deletions

diff --git a/docs/docs/testing.md b/docs/docs/testing.md
index 879e319..d340868 100644
--- a/docs/docs/testing.md
+++ b/docs/docs/testing.md
@@ -5,7 +5,7 @@ layout: docs
 
 ## Workers inside unit tests
 
-You may wish to include your RQ tasks inside unit tests. However many frameworks (such as Django) use in-memory databases which do not play nicely with the default `fork()` behaviour of RQ.
+You may wish to include your RQ tasks inside unit tests. However, many frameworks (such as Django) use in-memory databases, which do not play nicely with the default `fork()` behaviour of RQ.
 
 Therefore, you must use the SimpleWorker class to avoid fork();
 
@@ -21,6 +21,25 @@ worker.work(burst=True)  # Runs enqueued job
 ```
 
 
+## Testing on Windows
+
+If you are testing on a Windows machine you can use the approach above, but with a slight tweak.
+You will need to subclass SimpleWorker to override the default timeout mechanism of the worker.
+Reason: Windows OS does not implement some underlying signals utilized by the default SimpleWorker.
+
+To subclass SimpleWorker for Windows you can do the following:
+
+```python
+from rq import SimpleWorker
+from rq.timeouts import TimerDeathPenalty
+
+class WindowsSimpleWorker(SimpleWorker):
+    death_penalty_class = TimerDeathPenalty
+```
+
+Now you can use WindowsSimpleWorker for running tasks on Windows.
+
+
 ## Running Jobs in unit tests
 
 Another solution for testing purposes is to use the `is_async=False` queue