Fixed test and added test for -a.

Author: excitoon

tests.py

@@ -9,8 +9,35 @@ def test_simple(self):
         env = {k: v for k, v in os.environ.items() if not k.endswith("_COLORS")}
         env["PYTHONUTF8"] = "1"
         process = subprocess.run(
-            os.path.abspath("3"),
-            shell=True,
+            [os.path.abspath("3")],
+            env=env,
+            stdout=subprocess.PIPE,
+        )
+        self.assertEqual(process.returncode, 0)
+        self.assertEqual(
+            process.stdout,
+            """
+.
+├── 3
+├── 3.cmd
+├── examples
+│   └── 3.png
+├── LICENSE.md
+├── pyproject.toml
+├── README.md
+├── requirements.txt
+├── setup.py
+└── tests.py
+
+1 directories, 9 files
+""".lstrip().encode(),
+        )
+
+    def test_all(self):
+        env = {k: v for k, v in os.environ.items() if not k.endswith("_COLORS")}
+        env["PYTHONUTF8"] = "1"
+        process = subprocess.run(
+            [os.path.abspath("3"), "-a"],
             env=env,
             stdout=subprocess.PIPE,
         )