Adding integration tests for the COLUMNS env variable support in stty

Author: ChrisDryden

src/uu/stty/src/stty.rs

@@ -500,7 +500,7 @@ struct WrappedPrinter {
 }
 
 impl WrappedPrinter {
-    fn new(term_size: &Option<TermSize>) -> Self {
+    fn new(term_size: Option<&TermSize>) -> Self {
         let columns = match term_size {
             Some(term_size) => term_size.columns,
             None => {
@@ -549,8 +549,8 @@ impl WrappedPrinter {
 fn print_terminal_size(
     termios: &Termios,
     opts: &Options,
-    window_size: &Option<TermSize>,
-    term_size: &Option<TermSize>,
+    window_size: Option<&TermSize>,
+    term_size: Option<&TermSize>,
 ) -> nix::Result<()> {
     let speed = cfgetospeed(termios);
     let mut printer = WrappedPrinter::new(window_size);
@@ -769,7 +769,7 @@ fn control_char_to_string(cc: nix::libc::cc_t) -> nix::Result<String> {
 fn print_control_chars(
     termios: &Termios,
     opts: &Options,
-    term_size: &Option<TermSize>,
+    term_size: Option<&TermSize>,
 ) -> nix::Result<()> {
     if !opts.all {
         // Print only control chars that differ from sane defaults
@@ -825,8 +825,7 @@ fn print_settings(termios: &Termios, opts: &Options) -> nix::Result<()> {
         let device_fd = opts.file.as_raw_fd();
         let term_size = {
             let mut term_size = TermSize::default();
-            let term_size =
-                unsafe { tiocgwinsz(device_fd, &raw mut term_size) }.map(|_| term_size);
+            let term_size = unsafe { tiocgwinsz(device_fd, &raw mut term_size) }.map(|_| term_size);
             if opts.all {
                 Some(term_size?)
             } else {
@@ -835,21 +834,21 @@ fn print_settings(termios: &Termios, opts: &Options) -> nix::Result<()> {
         };
 
         let stdout_fd = stdout().as_raw_fd();
-        let window_size = if device_fd != stdout_fd {
+        let window_size = if device_fd == stdout_fd {
+            &term_size
+        } else {
             let mut term_size = TermSize::default();
             &unsafe { tiocgwinsz(stdout_fd, &raw mut term_size) }
                 .map(|_| term_size)
                 .ok()
-        } else {
-            &term_size
         };
 
-        print_terminal_size(termios, opts, &window_size, &term_size)?;
-        print_control_chars(termios, opts, &window_size)?;
-        print_flags(termios, opts, CONTROL_FLAGS, &window_size);
-        print_flags(termios, opts, INPUT_FLAGS, &window_size);
-        print_flags(termios, opts, OUTPUT_FLAGS, &window_size);
-        print_flags(termios, opts, LOCAL_FLAGS, &window_size);
+        print_terminal_size(termios, opts, window_size.as_ref(), term_size.as_ref())?;
+        print_control_chars(termios, opts, window_size.as_ref())?;
+        print_flags(termios, opts, CONTROL_FLAGS, window_size.as_ref());
+        print_flags(termios, opts, INPUT_FLAGS, window_size.as_ref());
+        print_flags(termios, opts, OUTPUT_FLAGS, window_size.as_ref());
+        print_flags(termios, opts, LOCAL_FLAGS, window_size.as_ref());
     }
     Ok(())
 }
@@ -858,7 +857,7 @@ fn print_flags<T: TermiosFlag>(
     termios: &Termios,
     opts: &Options,
     flags: &[Flag<T>],
-    term_size: &Option<TermSize>,
+    term_size: Option<&TermSize>,
 ) {
     let mut printer = WrappedPrinter::new(term_size);
     for &Flag {

tests/by-util/test_stty.rs

@@ -349,3 +349,59 @@ fn non_negatable_combo() {
         .fails()
         .stderr_contains("invalid argument '-ek'");
 }
+
+#[test]
+#[cfg(unix)]
+fn test_columns_env_wrapping() {
+    let (path, _controller, _replica) = pty_path();
+
+    // Must pipe output so stty uses COLUMNS env instead of actual terminal size
+    for (columns, max_len) in [(20, 20), (40, 40), (50, 50)] {
+        let result = new_ucmd!()
+            .args(&["--all", "--file", &path])
+            .env("COLUMNS", columns.to_string())
+            .set_stdout(Stdio::piped())
+            .succeeds();
+
+        for line in result.stdout_str().lines() {
+            assert!(
+                line.len() <= max_len,
+                "Line exceeds COLUMNS={columns}: '{line}'"
+            );
+        }
+    }
+
+    // Wide columns should allow longer lines
+    let result = new_ucmd!()
+        .args(&["--all", "--file", &path])
+        .env("COLUMNS", "200")
+        .set_stdout(Stdio::piped())
+        .succeeds();
+    let has_long_line = result.stdout_str().lines().any(|line| line.len() > 80);
+    assert!(
+        has_long_line,
+        "Expected at least one line longer than 80 chars with COLUMNS=200"
+    );
+
+    // Invalid values should fall back to default
+    for invalid in ["invalid", "0", "-10"] {
+        new_ucmd!()
+            .args(&["--all", "--file", &path])
+            .env("COLUMNS", invalid)
+            .set_stdout(Stdio::piped())
+            .succeeds();
+    }
+
+    // Without --all flag
+    let result = new_ucmd!()
+        .args(&["--file", &path])
+        .env("COLUMNS", "30")
+        .set_stdout(Stdio::piped())
+        .succeeds();
+    for line in result.stdout_str().lines() {
+        assert!(
+            line.len() <= 30,
+            "Line exceeds COLUMNS=30 without --all: '{line}'"
+        );
+    }
+}