Reduce the slowest test costs without changing production behavior

Profiling with pytest --durations=10 identified four clear outliers:
a debug-toggle test highlighting cmd2's source and three successful-pipe
tests waiting through the production startup probe.

Keep real traceback rendering but suppress source highlighting in the
debug-toggle test. For successful-pipe tests, model the startup probe's
timeout while preserving real subprocess I/O and completion waits.
Early-exit detection remains covered by its separate deterministic test.

Local parallel-run timings (Python 3.14 free-threaded, macOS):

| Test                            | Before | After |
|---------------------------------|--------|-------|
| test_base_debug                 | 0.31s  | 0.01s |
| test_pipe_to_shell               | 0.22s  | 0.03s |
| test_piping_uses_utf8            | 0.22s  | 0.05s |
| test_pipe_to_shell_and_redirect  | 0.21s  | 0.05s |

Full-suite parallel time: 3.14s -> 2.61s.
Full-suite serial time:   7.06s -> 6.18s.
The remaining top-ten entries were around 0.05s each and were left intact.

Validation: 1,864 passed, 2 skipped; coverage unchanged at 99.4%.
make check and make docs-test passed.

Author: tleonhardt

tests/conftest.py

@@ -1,6 +1,7 @@
 """Cmd2 unit/functional testing"""
 
 import os
+import subprocess
 import sys
 from collections.abc import Callable
 from contextlib import redirect_stderr
@@ -110,6 +111,24 @@ def fixed_terminal_size(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(os, "get_terminal_size", lambda fd=1: os.terminal_size((80, 24)))
 
 
+@pytest.fixture
+def running_pipe_process(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Exercise real pipe I/O without the failed-start detection delay.
+
+    Successful-pipe tests need a running child, not a timed startup probe. Model
+    that probe's timeout, but keep real unbounded waits so subprocess output and
+    exit are still observed. Early-exit handling has its own deterministic test.
+    """
+    wait = subprocess.Popen.wait
+
+    def wait_without_probe(process, timeout=None):
+        if timeout is not None:
+            raise subprocess.TimeoutExpired(process.args, timeout)
+        return wait(process)
+
+    monkeypatch.setattr(subprocess.Popen, "wait", wait_without_probe)
+
+
 @pytest.fixture
 def base_app() -> cmd2.Cmd:
     return cmd2.Cmd(include_py=True, include_ipy=True)

tests/test_cmd2.py

@@ -843,7 +843,7 @@ def test_disallow_redirection(redirection_app: RedirectionApp, capsys: pytest.Ca
     assert not os.path.exists(filename)
 
 
-def test_pipe_to_shell(redirection_app: RedirectionApp, capsys: pytest.CaptureFixture[str]) -> None:
+def test_pipe_to_shell(redirection_app: RedirectionApp, capsys: pytest.CaptureFixture[str], running_pipe_process) -> None:
     out, err = run_cmd(redirection_app, "print_output | sort")
 
     # Verify print() went to sys.stdout
@@ -856,7 +856,7 @@ def test_pipe_to_shell(redirection_app: RedirectionApp, capsys: pytest.CaptureFi
     assert not err
 
 
-def test_pipe_to_shell_and_redirect(redirection_app) -> None:
+def test_pipe_to_shell_and_redirect(redirection_app, running_pipe_process) -> None:
     filename = "out.txt"
     out, err = run_cmd(redirection_app, f"print_output | sort > {filename}")
     assert not out
@@ -962,6 +962,9 @@ def test_base_timing(base_app) -> None:
 
 
 def test_base_debug(base_app) -> None:
+    # Verify the debug toggle and real traceback, without syntax-highlighting the
+    # entire cmd2 source file just to assert the traceback header.
+    base_app.traceback_kwargs["suppress"] = [cmd2]
     # Purposely set the editor to None
     base_app.editor = None
 

tests/test_suite_environment.py

@@ -63,7 +63,7 @@ def test_redirection_to_a_file_uses_utf8(tmp_path) -> None:
 PASS_THROUGH = "import sys; sys.stdin.reconfigure(encoding='utf-8'); sys.stdout.write(sys.stdin.read())"
 
 
-def test_piping_uses_utf8(tmp_path) -> None:
+def test_piping_uses_utf8(tmp_path, running_pipe_process) -> None:
     """The same applies to the pipe the subprocess reads from."""
     app = EncodingProbe(allow_cli_args=False)
     target = tmp_path / "piped.txt"