Use os.execv instead of subprocess.run when no further action is taken.

This prevents the underlying file from being marked busy while a
long-running action is happening (e.g. eureka is open).

tests/play_test.py

@@ -1,16 +1,16 @@
 import cliff.app
 import dcc.play
 import logging
+import os
 import mockito.matchers
 import pathlib
-import subprocess
 import tempfile
 
 
 logger = logging.getLogger(__name__)
 
 
-def test_play(when):
+def test_play(expect):
     with tempfile.TemporaryDirectory() as td:
         tdp = pathlib.Path(td)
         tdp.joinpath("config.toml").write_text(
@@ -26,9 +26,14 @@ def test_play(when):
         scp.mkdir()
         scp.joinpath("config.toml").touch()
         scp.joinpath("scythe.wad").touch()
-        zero = subprocess.CompletedProcess
-        zero.returncode = 0
-        when(subprocess).run(
+        dcc.play.Play.__init__ = lambda self: None
+        dcc.play.Play.get_epilog = lambda self: ""
+        rig = dcc.play.Play()
+        rig._hooks = []
+        parser = rig.get_parser("test_play")
+        parsed_args = parser.parse_args(args=["--doom", td, "scythe", "01"])
+        with expect(os, times=1).execv(
+            tdp.joinpath("dsda-doom").joinpath("exe"),
             [
                 tdp.joinpath("dsda-doom").joinpath("exe"),
                 "-iwad",
@@ -42,11 +47,5 @@ def test_play(when):
                 "-warp",
                 "01",
             ]
-        ).thenReturn(zero)
-        dcc.play.Play.__init__ = lambda self: None
-        dcc.play.Play.get_epilog = lambda self: ""
-        rig = dcc.play.Play()
-        rig._hooks = []
-        parser = rig.get_parser("test_play")
-        parsed_args = parser.parse_args(args=["--doom", td, "scythe", "01"])
-        assert rig.run(parsed_args) == 0
+        ).thenReturn(None):
+            assert rig.run(parsed_args) is None