Adding tests for ls. Corrected issue with ls on the present directory throwing panic!()

Cargo.lock

@@ -35,6 +35,7 @@ dependencies = [
  "link 0.0.1",
  "ln 0.0.1",
  "logname 0.0.1",
+ "ls 0.0.1",
  "memchr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "mkdir 0.0.1",
  "mkfifo 0.0.1",
@@ -448,6 +449,16 @@ dependencies = [
  "uucore 0.0.1",
 ]
 
+[[package]]
+name = "ls"
+version = "0.0.1"
+dependencies = [
+ "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pretty-bytes 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "uucore 0.0.1",
+]
+
 [[package]]
 name = "memchr"
 version = "0.1.7"
@@ -571,6 +582,15 @@ dependencies = [
  "uucore 0.0.1",
 ]
 
+[[package]]
+name = "pretty-bytes"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "primal"
 version = "0.2.3"

Makefile

@@ -146,6 +146,7 @@ TEST_PROGS  := \
 	head \
 	link \
 	ln \
+    ls \
 	mkdir \
 	mktemp \
 	mv \

src/ls/ls.rs

@@ -89,8 +89,7 @@ fn help() {
 
 fn list(options: getopts::Matches) {
     let locs: Vec<String> = if options.free.is_empty() {
-        show_error!("Missing DIRECTORY or FILES argument. Try --help.");
-        panic!();
+        vec![String::from(".")]
     } else {
         options.free.iter().cloned().collect()
     };

tests/ls.rs

@@ -0,0 +1,16 @@
+#[macro_use]
+mod common;
+
+use common::util::*;
+
+static UTIL_NAME: &'static str = "ls";
+
+#[test]
+fn test_ls_ls() {
+    let (at, mut ucmd) = testing(UTIL_NAME);
+    
+    let result = ucmd.run();
+    
+    let exit_success = result.success;
+    assert_eq!(exit_success, true);
+}