diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 96f90c98..0a7b2969 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -38,7 +38,6 @@ jobs:
             build-essential debhelper dh-python dh-apparmor
           git config --global --add safe.directory "$GITHUB_WORKSPACE"
       - uses: actions/checkout@v4
-
       - name: Test build
         run: |
           dpkg-buildpackage -b -i -us -uc
@@ -47,3 +46,5 @@ jobs:
         run: |
           set -o xtrace
           ./run-tests
+          git clone https://github.com/nickboucher/trojan-source
+          ./unicode-testscript
diff --git a/pyproject.toml b/pyproject.toml
index 66ae5607..010fdd41 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,6 +2,8 @@
 line-length = 79
 [tool.mypy]
 strict="yes"
+[tool.pylint.'SIMILARITIES']
+min-similarity-lines=10
 [tool.pylint.'FORMAT']
 expected-line-ending-format="LF"
 max-line-length=79
diff --git a/run-tests b/run-tests
index 1ad52aa1..e9accb5c 100755
--- a/run-tests
+++ b/run-tests
@@ -5,13 +5,14 @@ pyrc="${git_toplevel}/pyproject.toml"
 pythonpath="${git_toplevel}/usr/lib/python3/dist-packages"
 export PYTHONPATH="${pythonpath}${PYTHONPATH+":${PYTHONPATH}"}"
 
-pytest=(python3 -m pytest -o 'python_files=*.py')
+pytest=(python3 -m pytest -o 'python_files=tests/*.py')
 black=(black --config="${pyrc}" --color --diff --check)
 pylint=(pylint --rcfile="${pyrc}")
 mypy=(mypy --config-file="${pyrc}")
 
 cd "${pythonpath}/stdisplay/"
-"${pytest[@]}" "${@}"
+# Ideally, these variables should be ignored by the tests...
+NO_COLOR="" COLORTERM="" TERM="xterm-direct" "${pytest[@]}" "${@}"
 "${black[@]}" .
 find . -type f -name "*.py" -print0 | xargs -0 "${pylint[@]}"
 "${mypy[@]}" .
diff --git a/unicode-testscript b/unicode-testscript
index da92c304..4f952e8e 100755
--- a/unicode-testscript
+++ b/unicode-testscript
@@ -3,23 +3,15 @@
 ## Copyright (C) 2025 - 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ## See the file COPYING for copying conditions.
 
-## NOTE:
-## Assumes folder 'trojan-source' in the home folder.
-##
-## cd ~
-## git clone git@github.com:nickboucher/trojan-source.git
-
-## TODO: Convert into proper unit test and/or CI.
-
 #set -x
 set -e
 set -o nounset
 set -o pipefail
 set -o errtrace
 
-if [ "$(id -u)" = 0 ]; then
-   printf "%s\n" "$0: ERROR: No need to run as root!" >&2
-   exit 1
+if [ "$(id -u)" = 0 ] && [ -z "${GITHUB_WORKSPACE:-}" ]; then
+    printf "%s\n" "$0: ERROR: No need to run as root!" >&2
+    exit 1
 fi
 
 folder_list="Assembly  Bash  C  C#  C++  Go  Java  JavaScript  Python  RegEx  Rust  Solidity"
diff --git a/usr/bin/stcat b/usr/bin/stcat
index da0cd351..54b7f924 100755
--- a/usr/bin/stcat
+++ b/usr/bin/stcat
@@ -1,25 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""Safely print stdin or file to stdout."""
-
-from fileinput import input as file_input
-from sys import stdin, stdout
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """Safely print stdin or file to stdout."""
-    stdin.reconfigure(errors="ignore")  # type: ignore
-    ## File input reads stdin when no file is provided or file is '-'.
-    for untrusted_text in file_input(encoding="ascii", errors="replace"):
-        stdout.write(stdisplay(untrusted_text))
-    stdout.flush()
-
+from stdisplay.stcat import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/bin/stcatn b/usr/bin/stcatn
index e649339e..a04f9fb9 100755
--- a/usr/bin/stcatn
+++ b/usr/bin/stcatn
@@ -1,31 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""
-Safely print stdin or file to stdout with tweaks
-(trim trailing whitespace, ensure final newline).
-"""
-
-from fileinput import input as file_input
-from sys import stdin, stdout
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """
-    main
-    """
-    stdin.reconfigure(errors="ignore")  # type: ignore
-
-    for line in file_input(encoding="ascii", errors="replace"):
-        stdout.write(stdisplay(line).rstrip() + "\n")
-
-    stdout.flush()
-
+from stdisplay.stcatn import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/bin/stecho b/usr/bin/stecho
index 4f3c02de..d9820854 100755
--- a/usr/bin/stecho
+++ b/usr/bin/stecho
@@ -1,24 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""Safely print argument to stdout with echo's formatting."""
-
-from sys import argv, stdout
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """Safely print argument to stdout with echo's formatting."""
-    if len(argv) > 1:
-        untrusted_text = " ".join(argv[1:])
-        stdout.write(stdisplay(untrusted_text))
-    stdout.write("\n")
-    stdout.flush()
-
+from stdisplay.stecho import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/bin/stprint b/usr/bin/stprint
index 6a2cc0dc..7f8c6d13 100755
--- a/usr/bin/stprint
+++ b/usr/bin/stprint
@@ -1,23 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""Safely print argument to stdout."""
-
-from sys import argv, stdout
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """Safely print argument to stdout."""
-    if len(argv) > 1:
-        untrusted_text = "".join(argv[1:])
-        stdout.write(stdisplay(untrusted_text))
-        stdout.flush()
-
+from stdisplay.stprint import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/bin/stsponge b/usr/bin/stsponge
index efb4d250..0af27420 100755
--- a/usr/bin/stsponge
+++ b/usr/bin/stsponge
@@ -1,35 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""Safely print stdin to stdout or file."""
-
-from sys import argv, stdin, stdout
-import shutil
-from tempfile import NamedTemporaryFile
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """Safely print stdin to stdout or file."""
-    untrusted_text_list = []
-    stdin.reconfigure(errors="ignore")  # type: ignore
-    for untrusted_text in stdin:
-        untrusted_text_list.append(untrusted_text)
-    if len(argv) == 1:
-        stdout.write(stdisplay("".join(untrusted_text_list)))
-        stdout.flush()
-    else:
-        with NamedTemporaryFile(mode="w", delete=False) as temp_file:
-            temp_file.write(stdisplay("".join(untrusted_text_list)))
-            temp_file.flush()
-        for file in argv[1:]:
-            shutil.copy2(temp_file.name, file)
-        temp_file.close()
-
+from stdisplay.stsponge import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/bin/sttee b/usr/bin/sttee
index 585ef224..8628a648 100755
--- a/usr/bin/sttee
+++ b/usr/bin/sttee
@@ -1,28 +1,12 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
 ## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
 ## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
 ##
 ## SPDX-License-Identifier: AGPL-3.0-or-later
 
-"""Safely print stdin to stdout and file."""
-from sys import argv, stdin, stdout
-from stdisplay.stdisplay import stdisplay
-
-
-def main() -> None:
-    """Safely print stdin to stdout and file."""
-    untrusted_text_list = []
-    stdin.reconfigure(errors="ignore")  # type: ignore
-    for untrusted_text in stdin:
-        untrusted_text_list.append(untrusted_text)
-        stdout.write(stdisplay(untrusted_text))
-    stdout.flush()
-    if len(argv) > 1:
-        for file_arg in argv[1:]:
-            with open(file_arg, mode="w", encoding="ascii") as file:
-                file.write(stdisplay("".join(untrusted_text_list)))
-
+from stdisplay.sttee import main
 
 if __name__ == "__main__":
     main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/stcat.py b/usr/lib/python3/dist-packages/stdisplay/stcat.py
new file mode 100755
index 00000000..9163d97a
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/stcat.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Safely print stdin or file to stdout."""
+
+from fileinput import input as file_input
+from sys import stdin, stdout, modules
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """Safely print stdin or file to stdout."""
+    # https://github.com/pytest-dev/pytest/issues/4843
+    if "pytest" not in modules:
+        stdin.reconfigure(errors="ignore")  # type: ignore
+    ## File input reads stdin when no file is provided or file is '-'.
+    for untrusted_text in file_input(encoding="ascii", errors="replace"):
+        stdout.write(stdisplay(untrusted_text))
+    stdout.flush()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/stcatn.py b/usr/lib/python3/dist-packages/stdisplay/stcatn.py
new file mode 100755
index 00000000..3abf9397
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/stcatn.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""
+Safely print stdin or file to stdout with tweaks
+(trim trailing whitespace, ensure final newline).
+"""
+
+from fileinput import input as file_input
+from sys import stdin, stdout, modules
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """
+    main
+    """
+    # https://github.com/pytest-dev/pytest/issues/4843
+    if "pytest" not in modules:
+        stdin.reconfigure(errors="ignore")  # type: ignore
+
+    for line in file_input(encoding="ascii", errors="replace"):
+        stdout.write(stdisplay(line).rstrip() + "\n")
+
+    stdout.flush()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/stecho.py b/usr/lib/python3/dist-packages/stdisplay/stecho.py
new file mode 100755
index 00000000..4f3c02de
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/stecho.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Safely print argument to stdout with echo's formatting."""
+
+from sys import argv, stdout
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """Safely print argument to stdout with echo's formatting."""
+    if len(argv) > 1:
+        untrusted_text = " ".join(argv[1:])
+        stdout.write(stdisplay(untrusted_text))
+    stdout.write("\n")
+    stdout.flush()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/stprint.py b/usr/lib/python3/dist-packages/stdisplay/stprint.py
new file mode 100755
index 00000000..6a2cc0dc
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/stprint.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Safely print argument to stdout."""
+
+from sys import argv, stdout
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """Safely print argument to stdout."""
+    if len(argv) > 1:
+        untrusted_text = "".join(argv[1:])
+        stdout.write(stdisplay(untrusted_text))
+        stdout.flush()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/stsponge.py b/usr/lib/python3/dist-packages/stdisplay/stsponge.py
new file mode 100755
index 00000000..9bcc97e2
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/stsponge.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Safely print stdin to stdout or file."""
+
+from sys import argv, stdin, stdout, modules
+import shutil
+from tempfile import NamedTemporaryFile
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """Safely print stdin to stdout or file."""
+    # https://github.com/pytest-dev/pytest/issues/4843
+    if "pytest" not in modules:
+        stdin.reconfigure(errors="ignore")  # type: ignore
+    untrusted_text_list = []
+    for untrusted_text in stdin:
+        untrusted_text_list.append(untrusted_text)
+    if len(argv) == 1:
+        stdout.write(stdisplay("".join(untrusted_text_list)))
+        stdout.flush()
+    else:
+        with NamedTemporaryFile(mode="w", delete=False) as temp_file:
+            temp_file.write(stdisplay("".join(untrusted_text_list)))
+            temp_file.flush()
+        for file in argv[1:]:
+            shutil.copy2(temp_file.name, file)
+        temp_file.close()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/sttee.py b/usr/lib/python3/dist-packages/stdisplay/sttee.py
new file mode 100755
index 00000000..ec1218fa
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/sttee.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+"""Safely print stdin to stdout and file."""
+from sys import argv, stdin, stdout, modules
+from stdisplay.stdisplay import stdisplay
+
+
+def main() -> None:
+    """Safely print stdin to stdout and file."""
+    # https://github.com/pytest-dev/pytest/issues/4843
+    if "pytest" not in modules:
+        stdin.reconfigure(errors="ignore")  # type: ignore
+    untrusted_text_list = []
+    for untrusted_text in stdin:
+        untrusted_text_list.append(untrusted_text)
+        stdout.write(stdisplay(untrusted_text))
+    stdout.flush()
+    if len(argv) > 1:
+        for file_arg in argv[1:]:
+            with open(file_arg, mode="w", encoding="ascii") as file:
+                file.write(stdisplay("".join(untrusted_text_list)))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/__init__.py b/usr/lib/python3/dist-packages/stdisplay/tests/__init__.py
old mode 100755
new mode 100644
index e5a0d9b4..0c7cf256
--- a/usr/lib/python3/dist-packages/stdisplay/tests/__init__.py
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/__init__.py
@@ -1 +1,99 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import importlib
+import os
+import shutil
+import sys
+import tempfile
+import unittest
+from typing import Optional, Any
+from test.support import captured_stdout, captured_stdin  # type: ignore
+from unittest.mock import patch
+from stdisplay.stdisplay import get_sgr_support
+
+
+class TestSTBase(unittest.TestCase):
+    """
+    Base class for testing safe terminal utilities.
+
+    Assign "self.module" to the module you want to try on the "setup()" using
+    "super()":
+
+    >>> class TestSTCat(stdisplay.tests.TestSTBase):
+    >>>     def setUp(self) -> None:
+    >>>         self.module = "stcat"
+    >>>         super().setUp()
+    """
+
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        self.text_dirty = "\x1b[0mTest\x1b[2Kor\x1b]1;is\x1b\n[m"
+        self.text_dirty_sanitized = "\x1b[0mTest_[2Kor_]1;is_\n[m"
+        super().__init__(*args, **kwargs)
+
+    def setUp(self) -> None:
+        self.tmpfiles_list = []
+        contents = ["a b\n", "c d"]
+        self.tmpdir = tempfile.mkdtemp()
+        for i in range(0, 6):
+            self.tmpfiles_list.append(os.path.join(self.tmpdir, str(i)))
+            with open(self.tmpfiles_list[i], "w", encoding="utf-8") as file:
+                if i == 0:
+                    file.write("")
+                elif i == 1:
+                    file.write("".join(contents))
+                elif i == 2:
+                    file.write("".join(contents) + "\n")
+                elif i == 3:
+                    file.write(self.text_dirty)
+                elif i in [4, 5]:
+                    pass
+                file.flush()
+                file.close()
+        self.tmpfiles = {
+            "empty": self.tmpfiles_list[0],
+            "raw": self.tmpfiles_list[1],
+            "newline": self.tmpfiles_list[2],
+            "dirty": self.tmpfiles_list[3],
+            "fill": self.tmpfiles_list[4],
+            "fill2": self.tmpfiles_list[5],
+        }
+
+    def tearDown(self) -> None:
+        shutil.rmtree(self.tmpdir)
+
+    def _del_module(self) -> None:
+        for module in ["stdisplay." + self.module]:  # type: ignore # pylint: disable=no-member
+            if module in sys.modules:
+                del sys.modules[module]
+            globals().pop(module, None)
+
+    # pylint: disable=too-many-arguments
+    def _test_util(
+        self,
+        argv: Optional[list[str]] = None,
+        stdin: Optional[str] = None,
+    ) -> str:
+        """
+        Helper function to pass stdin.
+        """
+        self._del_module()
+        if argv is None:
+            argv = [self.module + ".py"]  # type: ignore # pylint: disable=no-member
+        else:
+            argv = [self.module + ".py"] + argv  # type: ignore # pylint: disable=no-member
+        with patch.object(
+            sys, "argv", argv
+        ), captured_stdout() as stdout, captured_stdin() as stdin_patch:
+            module = importlib.import_module("stdisplay." + self.module)  # type: ignore # pylint: disable=no-member
+            if stdin is not None:
+                stdin_patch.write(stdin)
+            stdin_patch.seek(0)
+            module.main()
+        result = str(stdout.getvalue())  # pylint: disable=no-member
+        return result
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stcat.py b/usr/lib/python3/dist-packages/stdisplay/tests/stcat.py
new file mode 100644
index 00000000..df7293db
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stcat.py
@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import unittest
+import stdisplay.tests
+
+
+class TestSTCat(stdisplay.tests.TestSTBase):
+    """
+    Test stcat.
+    """
+
+    def setUp(self) -> None:
+        self.module = "stcat"
+        super().setUp()
+
+    def test_stcat_stdin(self) -> None:
+        """
+        Test passing stdin.
+        """
+        self.assertEqual("", self._test_util())
+        self.assertEqual("", self._test_util(stdin=""))
+        self.assertEqual("", self._test_util(argv=["-"]))
+        self.assertEqual("a b", self._test_util(stdin="a b"))
+        self.assertEqual(
+            "a b",
+            self._test_util(argv=["-"], stdin="a b"),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            self._test_util(stdin=self.text_dirty),
+        )
+
+    def test_stcat_file(self) -> None:
+        """
+        Test passing files.
+        """
+        cases = [
+            ("", [self.tmpfiles["empty"], self.tmpfiles["empty"]]),
+            ("a b\nc d", [self.tmpfiles["empty"], self.tmpfiles["raw"]]),
+            (
+                "a b\nc d\n",
+                [self.tmpfiles["empty"], self.tmpfiles["newline"]],
+            ),
+            (
+                "a b\nc da b\nc d\n",
+                [self.tmpfiles["raw"], self.tmpfiles["newline"]],
+            ),
+            (self.text_dirty_sanitized, [self.tmpfiles["dirty"]]),
+        ]
+        for text, argv in cases:
+            with self.subTest(text=text, argv=argv):
+                self.assertEqual(text, self._test_util(argv=argv))
+
+        self.assertEqual(
+            "a b\nc d",
+            self._test_util(stdin="is ignored", argv=[self.tmpfiles["raw"]]),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stcatn.py b/usr/lib/python3/dist-packages/stdisplay/tests/stcatn.py
new file mode 100644
index 00000000..b330bd28
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stcatn.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import unittest
+import stdisplay.tests
+
+
+class TestSTCatn(stdisplay.tests.TestSTBase):
+    """
+    Test stcatn.
+    """
+
+    def setUp(self) -> None:
+        self.module = "stcatn"
+        super().setUp()
+
+    def test_stcatn_file(self) -> None:
+        """
+        Test passing files.
+        """
+        cases = [
+            ("a b\nc d\n", [self.tmpfiles["raw"]]),
+            (
+                "a b\nc d\na b\nc d\n",
+                [self.tmpfiles["raw"], self.tmpfiles["raw"]],
+            ),
+            (self.text_dirty_sanitized + "\n", [self.tmpfiles["dirty"]]),
+        ]
+        for text, argv in cases:
+            with self.subTest(text=text, argv=argv):
+                self.assertEqual(text, self._test_util(argv=argv))
+
+        self.assertEqual(
+            "a b\nc d\n",
+            self._test_util(stdin="is ignored", argv=[self.tmpfiles["raw"]]),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stdisplay.py b/usr/lib/python3/dist-packages/stdisplay/tests/stdisplay.py
old mode 100755
new mode 100644
index 9d609d72..d6a61638
--- a/usr/lib/python3/dist-packages/stdisplay/tests/stdisplay.py
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stdisplay.py
@@ -1,5 +1,10 @@
 #!/usr/bin/env python3
 
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
 """
 Test the stdisplay module.
 """
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stecho.py b/usr/lib/python3/dist-packages/stdisplay/tests/stecho.py
new file mode 100644
index 00000000..f943ce38
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stecho.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import unittest
+import stdisplay.tests
+
+
+class TestSTEcho(stdisplay.tests.TestSTBase):
+    """
+    Test stecho.
+    """
+
+    def setUp(self) -> None:
+        self.module = "stecho"
+        super().setUp()
+
+    def test_stecho(self) -> None:
+        """
+        Test stecho.
+        """
+        self.assertEqual("\n", self._test_util())
+        self.assertEqual("\n", self._test_util(argv=[""]))
+        self.assertEqual("\n", self._test_util(stdin="no stdin"))
+        self.assertEqual("a b\n", self._test_util(argv=["a b"]))
+        self.assertEqual("a b\n", self._test_util(argv=["a", "b"]))
+        self.assertEqual(
+            self.text_dirty_sanitized + "\n",
+            self._test_util(argv=[self.text_dirty]),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stprint.py b/usr/lib/python3/dist-packages/stdisplay/tests/stprint.py
index 7c07d3c3..1ce9ebcd 100755
--- a/usr/lib/python3/dist-packages/stdisplay/tests/stprint.py
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stprint.py
@@ -1,20 +1,51 @@
 #!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
 
-"""
-Test the stprint module.
-"""
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
 
 import os
-import unittest
 import subprocess
+import unittest
 from stdisplay.stdisplay import (
     get_sgr_support,
 )
+import stdisplay.tests
 
 
-class TestSTPrint(unittest.TestCase):
+class TestSTPrint(stdisplay.tests.TestSTBase):
     """
-    Test stprint
+    Test stprint.
+    """
+
+    def setUp(self) -> None:
+        self.module = "stprint"
+        super().setUp()
+
+    def test_stprint(self) -> None:
+        """
+        Test without argument.
+        """
+        self.assertEqual("", self._test_util())
+        self.assertEqual("", self._test_util(argv=[""]))
+        self.assertEqual("", self._test_util(stdin="no stdin"))
+        self.assertEqual(
+            "a b", self._test_util(stdin="no stdin", argv=["a b"])
+        )
+        self.assertEqual("ab", self._test_util(argv=["a", "b"]))
+        self.assertEqual(
+            self.text_dirty_sanitized, self._test_util(argv=[self.text_dirty])
+        )
+
+
+class TestSTPrintShell(unittest.TestCase):
+    """
+    Test stdisplay with environment variables using stprint.
+
+    This class only exists because the developer could not find a way to patch
+    the environment variables correctly on the base class functions.
     """
 
     # pylint: disable=too-many-arguments
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/stsponge.py b/usr/lib/python3/dist-packages/stdisplay/tests/stsponge.py
new file mode 100644
index 00000000..354b11ca
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/stsponge.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-module-docstring disable=duplicate-code
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import unittest
+from pathlib import Path
+import stdisplay.tests
+
+
+class TestSTSponge(stdisplay.tests.TestSTBase):
+    """
+    Test stsponge.
+    """
+
+    def setUp(self) -> None:
+        self.module = "stsponge"
+        super().setUp()
+
+    def test_stsponge(self) -> None:
+        """
+        Test stsponge.
+        """
+        self.assertEqual("", self._test_util())
+        self.assertEqual("", self._test_util(stdin=""))
+        self.assertEqual("stdin", self._test_util(stdin="stdin"))
+        # Empty stdin with file argument produces empty stdout and file.
+        self.assertEqual("", self._test_util(argv=[self.tmpfiles["fill"]]))
+        self.assertEqual(
+            "",
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        # Empty stdout when writing to file and file sanitization.
+        self.assertEqual(
+            "",
+            self._test_util(
+                stdin=self.text_dirty, argv=[self.tmpfiles["fill"]]
+            ),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        # Empty stdout when writing to multiple files and its sanitization.
+        self.assertEqual(
+            "",
+            self._test_util(
+                stdin=self.text_dirty,
+                argv=[self.tmpfiles["fill"], self.tmpfiles["fill2"]],
+            ),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill2"]).read_text(encoding="utf-8"),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/usr/lib/python3/dist-packages/stdisplay/tests/sttee.py b/usr/lib/python3/dist-packages/stdisplay/tests/sttee.py
new file mode 100644
index 00000000..c931bd25
--- /dev/null
+++ b/usr/lib/python3/dist-packages/stdisplay/tests/sttee.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+# pylint: disable=missing-module-docstring
+
+## SPDX-FileCopyrightText: 2025 Benjamin Grande M. S. <ben.grande.b@gmail.com>
+## SPDX-FileCopyrightText: 2025 ENCRYPTED SUPPORT LLC <adrelanos@whonix.org>
+##
+## SPDX-License-Identifier: AGPL-3.0-or-later
+
+import unittest
+from pathlib import Path
+import stdisplay.tests
+
+
+class TestSTTee(stdisplay.tests.TestSTBase):
+    """
+    Test sttee
+    """
+
+    def setUp(self) -> None:
+        self.module = "sttee"
+        super().setUp()
+
+    def test_sttee(self) -> None:
+        """
+        Test sttee.
+        """
+        self.assertEqual("", self._test_util())
+        self.assertEqual("", self._test_util(stdin=""))
+        self.assertEqual("stdin", self._test_util(stdin="stdin"))
+        # Empty stdin with file argument.
+        self.assertEqual("", self._test_util(argv=[self.tmpfiles["fill"]]))
+        self.assertEqual(
+            "",
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        # Stdin sanitization and writing to file.
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            self._test_util(
+                stdin=self.text_dirty, argv=[self.tmpfiles["fill"]]
+            ),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        # Stdin sanitization and writing to multiple files.
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            self._test_util(
+                stdin=self.text_dirty,
+                argv=[self.tmpfiles["fill"], self.tmpfiles["fill2"]],
+            ),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill"]).read_text(encoding="utf-8"),
+        )
+        self.assertEqual(
+            self.text_dirty_sanitized,
+            Path(self.tmpfiles["fill2"]).read_text(encoding="utf-8"),
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()