false,true: Add by-util tests for options

tests/by-util/test_false.rs

@@ -1,6 +1,45 @@
 use crate::common::util::*;
+#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "netbsd"))]
+use std::fs::OpenOptions;
 
 #[test]
 fn test_exit_code() {
     new_ucmd!().fails();
 }
+
+#[test]
+fn test_version() {
+    new_ucmd!()
+        .args(&["--version"])
+        .fails()
+        .stdout_contains("false");
+}
+
+#[test]
+fn test_help() {
+    new_ucmd!()
+        .args(&["--help"])
+        .fails()
+        .stdout_contains("false");
+}
+
+#[test]
+fn test_short_options() {
+    for option in ["-h", "-v"] {
+        new_ucmd!().arg(option).fails().stdout_is("");
+    }
+}
+
+#[test]
+#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "netbsd"))]
+fn test_full() {
+    for option in ["--version", "--help"] {
+        let dev_full = OpenOptions::new().write(true).open("/dev/full").unwrap();
+
+        new_ucmd!()
+            .arg(option)
+            .set_stdout(dev_full)
+            .fails()
+            .stderr_contains("No space left on device");
+    }
+}

tests/by-util/test_true.rs

@@ -1,6 +1,45 @@
 use crate::common::util::*;
+#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "netbsd"))]
+use std::fs::OpenOptions;
 
 #[test]
 fn test_exit_code() {
     new_ucmd!().succeeds();
 }
+
+#[test]
+fn test_version() {
+    new_ucmd!()
+        .args(&["--version"])
+        .succeeds()
+        .stdout_contains("true");
+}
+
+#[test]
+fn test_help() {
+    new_ucmd!()
+        .args(&["--help"])
+        .succeeds()
+        .stdout_contains("true");
+}
+
+#[test]
+fn test_short_options() {
+    for option in ["-h", "-v"] {
+        new_ucmd!().arg(option).succeeds().stdout_is("");
+    }
+}
+
+#[test]
+#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "netbsd"))]
+fn test_full() {
+    for option in ["--version", "--help"] {
+        let dev_full = OpenOptions::new().write(true).open("/dev/full").unwrap();
+
+        new_ucmd!()
+            .arg(option)
+            .set_stdout(dev_full)
+            .fails()
+            .stderr_contains("No space left on device");
+    }
+}