nice: move from getopts to clap #1794

tests/by-util/test_nice.rs

@@ -1 +1,56 @@
-// ToDO: add tests
+use crate::common::util::*;
+
+#[test]
+fn test_get_current_niceness() {
+    // NOTE: this assumes the test suite is being run with a default niceness
+    // of 0, which may not necessarily be true
+    new_ucmd!().run().stdout_is("0\n");
+}
+
+#[test]
+fn test_negative_adjustment() {
+    // This assumes the test suite is run as a normal (non-root) user, and as
+    // such attempting to set a negative niceness value will be rejected by
+    // the OS.  If it gets denied, then we know a negative value was parsed
+    // correctly.
+
+    let res = new_ucmd!().args(&["-n", "-1", "true"]).run();
+    assert!(res.stderr.starts_with("nice: warning: setpriority: Permission denied"));
+}
+
+#[test]
+fn test_adjustment_with_no_command_should_error() {
+    new_ucmd!()
+    .args(&["-n", "19"])
+    .run()
+    .stderr_is("nice: error: A command must be given with an adjustment.\nTry \"nice --help\" for more information.\n");
+}
+
+#[test]
+fn test_command_with_no_adjustment() {
+    new_ucmd!().args(&["echo", "a"]).run().stdout_is("a\n");
+}
+
+#[test]
+fn test_command_with_no_args() {
+    new_ucmd!()
+        .args(&["-n", "19", "echo"])
+        .run()
+        .stdout_is("\n");
+}
+
+#[test]
+fn test_command_with_args() {
+    new_ucmd!()
+        .args(&["-n", "19", "echo", "a", "b", "c"])
+        .run()
+        .stdout_is("a b c\n");
+}
+
+#[test]
+fn test_command_where_command_takes_n_flag() {
+    new_ucmd!()
+        .args(&["-n", "19", "echo", "-n", "a"])
+        .run()
+        .stdout_is("a");
+}