test: fix save-signal test

Author: nedbat

coverage/cmdline.py

@@ -822,7 +822,7 @@ def do_help(
 
     def do_signal_save(self, _signum: int, _frame: types.FrameType | None) -> None:
         """ Signal handler to save coverage report """
-        print("Saving coverage data ...")
+        print("Saving coverage data ...", flush=True)
         self.coverage.save()
 
     def do_run(self, options: optparse.Values, args: list[str]) -> int:

tests/helpers.py

@@ -13,6 +13,7 @@
 import os
 import os.path
 import re
+import shlex
 import shutil
 import subprocess
 import sys
@@ -47,7 +48,7 @@ def _correct_encoding() -> str:
     return encoding
 
 
-def subprocess_popen(cmd: str) -> subprocess.Popen[bytes]:
+def subprocess_popen(cmd: str, shell=True) -> subprocess.Popen[bytes]:
     """Run a command in a subprocess.
 
     Returns the Popen object.
@@ -66,9 +67,12 @@ def subprocess_popen(cmd: str) -> subprocess.Popen[bytes]:
     sub_env = dict(os.environ)
     sub_env["PYTHONIOENCODING"] = _correct_encoding()
 
+    if not shell:
+        cmd = shlex.split(cmd)
+
     proc = subprocess.Popen(
         cmd,
-        shell=True,
+        shell=shell,
         env=sub_env,
         stdin=subprocess.PIPE,
         stdout=subprocess.PIPE,

tests/test_process.py

@@ -465,21 +465,29 @@ def test_os_exit(self, patch: bool) -> None:
     def test_save_signal(self, send: bool) -> None:
         self.make_file("loop.py", """\
             import time
+            print("Starting", flush=True)
             while True:
                 time.sleep(.01)
             """)
-        proc = subprocess_popen("coverage run --save-signal=USR1 loop.py")
+        proc = subprocess_popen("coverage run --save-signal=USR1 loop.py", shell=False)
         time.sleep(.25)
         if send:
             proc.send_signal(signal.SIGUSR1)
-            time.sleep(.91)
+            time.sleep(.1)
         proc.kill()
-        proc.communicate()
-        proc.wait()
+        proc.wait(timeout=.25)
+        stdout, _ = proc.communicate()
+        if not env.PYPY:
+            # Not sure why, PyPy doesn't get the output.
+            assert b"Starting" in stdout
         if send:
             self.assert_exists(".coverage")
+            if not env.PYPY:
+                assert b"Saving coverage data" in stdout
         else:
             self.assert_doesnt_exist(".coverage")
+            if not env.PYPY:
+                assert b"Saving coverage data" not in stdout
 
     def test_warnings_during_reporting(self) -> None:
         # While fixing issue #224, the warnings were being printed far too