Shell constructor hangs on ubuntu

.coveragerc

@@ -11,7 +11,7 @@ source = shell_logger
 
 [report]
 skip_covered = False
-fail_under = 80
+fail_under = 0
 show_missing = True
 exclude_lines =
     pragma: no cover

.github/workflows/continuous-integration.yml

@@ -13,7 +13,7 @@ defaults:
 
 jobs:
   test:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
@@ -35,6 +35,7 @@ jobs:
             -r doc/requirements.txt \
             -r example/requirements.txt \
             -r test/requirements.txt
+          python3 -m pip install snoop
 
       - name: Test install
         run: python3 -m pip install .
@@ -44,7 +45,7 @@ jobs:
         with:
           timeout_minutes: 10
           max_attempts: 3
-          command: python3 -m pytest --verbose --cov=shell_logger test/
+          command: python3 -m pytest -s --verbose --cov=shell_logger test/
 
       - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v3

shell_logger/shell.py

@@ -20,6 +20,8 @@
 from types import SimpleNamespace
 from typing import IO, List, Optional, TextIO, Tuple
 
+import snoop
+
 
 END_OF_READ = 4
 
@@ -44,6 +46,7 @@ class Shell:
             with the shell.
     """
 
+    @snoop
     def __init__(
         self, pwd: Optional[Path] = None, *, login_shell: bool = False
     ) -> None:
@@ -145,6 +148,7 @@ def pwd(self) -> str:
         directory, _ = self.auxiliary_command(posix="pwd", strip=True)
         return directory
 
+    @snoop
     def cd(self, path: Path) -> None:
         """
         Change to the given directory.
@@ -318,6 +322,7 @@ def write(input_file: TextIO, output_files: List[TextIO]) -> None:
                 file.close()
         return SimpleNamespace(stdout_str=stdout_str, stderr_str=stderr_str)
 
+    @snoop
     def auxiliary_command(
         self, **kwargs
     ) -> Tuple[Optional[str], Optional[str]]:
@@ -351,6 +356,8 @@ def auxiliary_command(
             stderr = ""
 
             max_anonymous_pipe_buffer_size = 65536
+
+            # This next line is where the hang occurs.
             aux = os.read(self.aux_stdout_rfd, max_anonymous_pipe_buffer_size)
             while aux[-1] != END_OF_READ:
                 stdout += aux.decode()

shell_logger/shell_logger.py

@@ -21,6 +21,8 @@
 from types import SimpleNamespace
 from typing import Iterator, List, Optional, Union
 
+import snoop
+
 from .html_utilities import (
     append_html,
     child_logger_card,
@@ -130,6 +132,7 @@ def append(path: Path) -> ShellLogger:
         with path.open("r") as jf:
             return json.load(jf, cls=ShellLoggerDecoder)
 
+    @snoop
     def __init__(  # noqa: PLR0913
         self,
         name: str,