date,comm,tty: add integration tests for write error handling

tests/by-util/test_comm.rs

@@ -727,3 +727,18 @@ fn test_read_error() {
         .fails()
         .stderr_contains("comm: /proc/self/mem: Input/output error");
 }
+
+#[test]
+#[cfg(unix)]
+fn test_comm_write_error_dev_full() {
+    use std::fs::OpenOptions;
+    let scene = TestScenario::new(util_name!());
+    scene.fixtures.write("a", "a\n");
+    let dev_full = OpenOptions::new().write(true).open("/dev/full").unwrap();
+    scene
+        .ucmd()
+        .args(&["a", "a"])
+        .set_stdout(dev_full)
+        .fails()
+        .stderr_contains("No space left on device");
+}

tests/by-util/test_date.rs

@@ -2066,3 +2066,15 @@ fn test_percent_percent_not_replaced() {
             .stdout_is(expected);
     }
 }
+
+#[test]
+#[cfg(unix)]
+fn test_date_write_error_dev_full() {
+    use std::fs::OpenOptions;
+    let dev_full = OpenOptions::new().write(true).open("/dev/full").unwrap();
+    new_ucmd!()
+        .arg("+%s")
+        .set_stdout(dev_full)
+        .fails()
+        .stderr_contains("write error");
+}

tests/by-util/test_tty.rs

@@ -87,3 +87,11 @@ fn test_stdout_fail() {
     let status = proc.wait().unwrap();
     assert_eq!(status.code(), Some(3));
 }
+
+#[test]
+#[cfg(unix)]
+fn test_version_pipe_no_stderr() {
+    let mut child = new_ucmd!().arg("--version").run_no_wait();
+    child.close_stdout();
+    child.wait().unwrap().no_stderr();
+}