vmstat: add tests

Author: Bluemangoo

src/uu/vmstat/src/picker.rs

@@ -65,6 +65,7 @@ pub fn get_pickers(matches: &ArgMatches) -> Vec<Picker> {
     ]
 }
 
+#[cfg(target_os = "linux")]
 fn with_unit(x: u64, arg: &ArgMatches) -> u64 {
     if let Some(unit) = arg.get_one::<String>("unit") {
         return match unit.as_str() {

src/uu/vmstat/src/vmstat.rs

@@ -8,6 +8,7 @@ mod picker;
 
 #[cfg(target_os = "linux")]
 use crate::picker::{get_pickers, Picker};
+#[allow(unused_imports)]
 use clap::{arg, crate_version, ArgMatches, Command};
 #[allow(unused_imports)]
 pub use parser::*;

tests/by-util/test_vmstat.rs

@@ -16,3 +16,14 @@ fn test_simple() {
 fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
 }
+
+#[test]
+fn test_unit() {
+    new_ucmd!().args(&["-S", "M"]).succeeds();
+}
+
+#[test]
+#[cfg(target_os = "linux")]
+fn test_invalid_unit() {
+    new_ucmd!().args(&["-S", "x"]).fails().code_is(1);
+}