vmstat: add simple tests

tests/by-util/test_vmstat.rs

@@ -0,0 +1,16 @@
+// This file is part of the uutils procps package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use crate::common::util::TestScenario;
+
+#[test]
+fn test_simple() {
+    new_ucmd!().succeeds();
+}
+
+#[test]
+fn test_invalid_arg() {
+    new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
+}

tests/tests.rs

@@ -49,6 +49,10 @@ mod test_pidwait;
 #[path = "by-util/test_top.rs"]
 mod test_top;
 
+#[cfg(feature = "vmstat")]
+#[path = "by-util/test_vmstat.rs"]
+mod test_vmstat;
+
 #[cfg(feature = "snice")]
 #[path = "by-util/test_snice.rs"]
 mod test_snice;