vmstat: add tests

Author: Bluemangoo

src/uu/vmstat/src/picker.rs

@@ -6,7 +6,6 @@
 #[cfg(target_os = "linux")]
 use crate::{CpuLoad, Meminfo, ProcData};
 use clap::ArgMatches;
-use uucore::error::USimpleError;
 
 #[cfg(target_os = "linux")]
 pub type Picker = (
@@ -65,17 +64,15 @@ 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() {
             "k" => x / bytesize::KB,
             "K" => x / bytesize::KIB,
             "m" => x / bytesize::MB,
             "M" => x / bytesize::MIB,
-            _ => panic!(
-                "{:?}",
-                USimpleError::new(1, "-S requires k, K, m or M (default is KiB)",)
-            ),
+            _ => x, // impossible
         };
     }
     x / bytesize::KIB

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::*;
@@ -24,6 +25,16 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let matches = uu_app().try_get_matches_from(args)?;
     #[cfg(target_os = "linux")]
     {
+        // validate unit
+        if let Some(unit) = matches.get_one::<String>("unit") {
+            if !["k", "K", "m", "M"].contains(&unit.as_str()) {
+                Err(USimpleError::new(
+                    1,
+                    "-S requires k, K, m or M (default is KiB)",
+                ))?
+            }
+        }
+
         let one_header = matches.get_flag("one-header");
         let no_first = matches.get_flag("no-first");
         let delay = matches.get_one::<String>("delay");

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);
+}