diff --git a/tests/by-util/test_pathchk.rs b/tests/by-util/test_pathchk.rs
index e24a464e0..d01beccc2 100644
--- a/tests/by-util/test_pathchk.rs
+++ b/tests/by-util/test_pathchk.rs
@@ -5,11 +5,152 @@ fn test_default_mode() {
     // test the default mode
 
     // accept some reasonable default
-    new_ucmd!().args(&["abc/def"]).succeeds().no_stdout();
+    new_ucmd!().args(&["dir/file"]).succeeds().no_stdout();
 
-    // fail on long inputs
+    // accept non-portable chars
+    new_ucmd!().args(&["dir#/$file"]).succeeds().no_stdout();
+
+    // accept empty path
+    new_ucmd!().args(&[""]).succeeds().no_stdout();
+
+    // fail on long path
     new_ucmd!()
-        .args(&["test".repeat(20000)])
+        .args(&["dir".repeat(libc::PATH_MAX as usize + 1)])
+        .fails()
+        .no_stdout();
+
+    // fail on long filename
+    new_ucmd!()
+        .args(&[format!(
+            "dir/{}",
+            "file".repeat(libc::FILENAME_MAX as usize + 1)
+        )])
         .fails()
         .no_stdout();
 }
+
+#[test]
+fn test_posix_mode() {
+    // test the posix mode
+
+    // accept some reasonable default
+    new_ucmd!().args(&["-p", "dir/file"]).succeeds().no_stdout();
+
+    // fail on long path
+    new_ucmd!()
+        .args(&[
+            "-p",
+            &"dir".repeat(libc::PATH_MAX as usize + 1).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on long filename
+    new_ucmd!()
+        .args(&[
+            "-p",
+            &format!("dir/{}", "file".repeat(libc::FILENAME_MAX as usize + 1)).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on non-portable chars
+    new_ucmd!().args(&["-p", "dir#/$file"]).fails().no_stdout();
+}
+
+#[test]
+fn test_posix_special() {
+    // test the posix special mode
+
+    // accept some reasonable default
+    new_ucmd!().args(&["-P", "dir/file"]).succeeds().no_stdout();
+
+    // accept non-portable chars
+    new_ucmd!()
+        .args(&["-P", "dir#/$file"])
+        .succeeds()
+        .no_stdout();
+
+    // accept non-leading hyphen
+    new_ucmd!()
+        .args(&["-P", "dir/file-name"])
+        .succeeds()
+        .no_stdout();
+
+    // fail on long path
+    new_ucmd!()
+        .args(&[
+            "-P",
+            &"dir".repeat(libc::PATH_MAX as usize + 1).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on long filename
+    new_ucmd!()
+        .args(&[
+            "-P",
+            &format!("dir/{}", "file".repeat(libc::FILENAME_MAX as usize + 1)).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on leading hyphen char
+    new_ucmd!().args(&["-P", "dir/-file"]).fails().no_stdout();
+
+    // fail on empty path
+    new_ucmd!().args(&["-P", ""]).fails().no_stdout();
+}
+
+#[test]
+fn test_posix_all() {
+    // test the posix special mode
+
+    // accept some reasonable default
+    new_ucmd!().args(&["-p", "-P", "dir/file"]).succeeds().no_stdout();
+
+    // accept non-leading hyphen
+    new_ucmd!()
+        .args(&["-p", "-P", "dir/file-name"])
+        .succeeds()
+        .no_stdout();
+
+    // fail on long path
+    new_ucmd!()
+        .args(&[
+            "-p",
+            "-P",
+            &"dir".repeat(libc::PATH_MAX as usize + 1).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on long filename
+    new_ucmd!()
+        .args(&[
+            "-p",
+            "-P",
+            &format!("dir/{}", "file".repeat(libc::FILENAME_MAX as usize + 1)).as_str(),
+        ])
+        .fails()
+        .no_stdout();
+
+    // fail on non-portable chars
+    new_ucmd!().args(&["-p", "-P", "dir#/$file"]).fails().no_stdout();
+
+    // fail on leading hyphen char
+    new_ucmd!().args(&["-p", "-P", "dir/-file"]).fails().no_stdout();
+
+    // fail on empty path
+    new_ucmd!().args(&["-p", "-P", ""]).fails().no_stdout();
+}
+
+#[test]
+fn test_args_parsing() {
+    // fail on no args
+    let empty_args: [String; 0] = [];
+    new_ucmd!()
+        .args(&empty_args)
+        .fails()
+        .no_stdout();
+}
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