On Windows, revert to subprocess.run instead of fileutils.run (Unix only)

Author: paulromano

CHANGELOG.md

@@ -10,21 +10,29 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 * RELAP-5 Plugin
+* MCNP Plugin
+* Serpent Plugin
 
 ### Changes
 
 * The `Plugin.__call__` method now allows arbitrary keyword arguments to be
   passed on to the `Plugin.run` method
 * The `Database` class now acts like a sequence
 * Database directory names use random strings to avoid clashes when multiple
-  instances of WATTS are running simulataneously
+  instances of WATTS are running simultaneously
 * File template-based plugins now accept an `extra_template_inputs` argument
   indicating extra template files that should be rendered
 * The `PluginOpenMC` class now takes an optional `function` argument that
   specifies an arbitrary execution sequence
 * All plugins consistently use an attribute `executable` for specifying the path
   to an executable
 
+### Fixed
+
+* Use non-blocking pipe when capturing output to avoid some plugins stalling.
+* Avoid use of Unix-specific features in the Python standard library when
+  running on Windows
+
 ## [0.2.0]
 
 ### Added

src/watts/fileutils.py

@@ -3,7 +3,6 @@
 
 from contextlib import contextmanager
 import errno
-import fcntl
 import os
 import platform
 import select
@@ -12,6 +11,9 @@
 import tempfile
 from typing import Union
 
+if sys.platform != 'win32':
+    import fcntl
+
 # Type for arguments that accept file paths
 PathLike = Union[str, bytes, os.PathLike]
 
@@ -93,6 +95,11 @@ def run(args):
     Based on https://stackoverflow.com/a/12272262 and
     https://stackoverflow.com/a/7730201
     """
+    # Windows doesn't support select.select and fcntl module so just default to
+    # using subprocess.run. In this case, show_output/show_stderr won't work.
+    if sys.platform == 'win32':
+        subprocess.run(args)
+        return
 
     # Helper function to add the O_NONBLOCK flag to a file descriptor
     def make_async(fd):