tr: add some tests

Makefile

@@ -61,6 +61,7 @@ TEST_PROGS  := \
   cat \
   mkdir \
   seq \
+  tr \
   truncate \
 
 TEST        ?= $(TEST_PROGS)

tr/test.rs

@@ -0,0 +1,33 @@
+use std::io::process::Command;
+
+fn run(input: &str, set1: &str, set2: &str) -> Vec<u8> {
+    let mut process = Command::new("build/tr").arg(set1).arg(set2).spawn().unwrap();
+
+    process.stdin.take_unwrap().write_str(input).unwrap();
+
+    let po = match process.wait_with_output() {
+        Ok(p) => p,
+        Err(err) => fail!("{}", err),
+    };
+    po.output
+}
+
+#[test]
+fn test_toupper() {
+    let out = run("!abcd!", "a-z", "A-Z");
+    assert_eq!(out.as_slice(), bytes!("!ABCD!"));
+}
+
+#[test]
+fn test_small_set2() {
+    let out = run("@0123456789", "0-9", "X");
+    assert_eq!(out.as_slice(), bytes!("@XXXXXXXXXX"));
+}
+
+#[test]
+fn test_unicode() {
+    let out = run("(,°□°）, ┬─┬", ", ┬─┬", "╯︵┻━┻");
+    assert_eq!(out.as_slice(), bytes!("(╯°□°）╯︵┻━┻"));
+}
+
+