test_matrix: Run Python subprocess via sys.executable.

This works better with pytest on Windows.

Signed-off-by: Anders Kaseorg <[email protected]>

Author: andersk

zulip/integrations/bridge_with_matrix/test_matrix.py

@@ -1,5 +1,6 @@
 import os
 import shutil
+import sys
 from contextlib import contextmanager
 from subprocess import PIPE, Popen
 from tempfile import mkdtemp
@@ -41,7 +42,7 @@ def new_temp_dir() -> Iterator[str]:
 class MatrixBridgeScriptTests(TestCase):
     def output_from_script(self, options: List[str]) -> List[str]:
         popen = Popen(
-            ["python", script] + options, stdin=PIPE, stdout=PIPE, universal_newlines=True
+            [sys.executable, script] + options, stdin=PIPE, stdout=PIPE, universal_newlines=True
         )
         return popen.communicate()[0].strip().split("\n")