Add initial tests for hashsum.

Makefile

@@ -167,6 +167,7 @@ TEST_PROGS  := \
   factor \
   false \
   fold \
+  hashsum \
   mkdir \
   mv \
   nl \

test/fixtures/hashsum/input.txt

@@ -0,0 +1 @@
+hello, world

test/fixtures/hashsum/md5.expected

@@ -0,0 +1 @@
+e4d7f1b4ed2e42d15898f4b27b019da4

test/fixtures/hashsum/sha1.expected

@@ -0,0 +1 @@
+b7e23ec29af22b0b4e41da31e868d57226121c84

test/fixtures/hashsum/sha224.expected

@@ -0,0 +1 @@
+6e1a93e32fb44081a401f3db3ef2e6e108b7bbeeb5705afdaf01fb27

test/fixtures/hashsum/sha256.expected

@@ -0,0 +1 @@
+09ca7e4eaa6e8ae9c7d261167129184883644d07dfba7cbfbc4c8a2e08360d5b

test/fixtures/hashsum/sha384.expected

@@ -0,0 +1 @@
+1fcdb6059ce05172a26bbe2a3ccc88ed5a8cd5fc53edfd9053304d429296a6da23b1cd9e5c9ed3bb34f00418a70cdb7e

test/fixtures/hashsum/sha512.expected

@@ -0,0 +1 @@
+8710339dcb6814d0d9d2290ef422285c9322b7163951f9a0ca8f883d3305286f44139aa374848e4174f5aada663027e4548637b6d19894aec4fb6c46a139fbf9

test/hashsum.rs

@@ -0,0 +1,99 @@
+use std::fs::File;
+use std::io::{Read, Write};
+use std::process::{Command, Stdio};
+use std::str::from_utf8;
+
+static PROGNAME: &'static str = "./hashsum";
+
+struct CmdResult {
+    success: bool,
+    stdout: String,
+    stderr: String,
+}
+
+fn run(cmd: &mut Command) -> CmdResult {
+    let prog = cmd.output().unwrap();
+    CmdResult {
+        success: prog.status.success(),
+        stdout: from_utf8(&prog.stdout).unwrap().to_string(),
+        stderr: from_utf8(&prog.stderr).unwrap().to_string(),
+    }
+}
+
+fn run_piped_stdin(cmd: &mut Command, input: &[u8])-> CmdResult {
+    let mut command = cmd
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .spawn()
+        .unwrap();
+
+    command.stdin
+        .take()
+        .unwrap_or_else(|| panic!("Could not take child process stdin"))
+        .write_all(input)
+        .unwrap_or_else(|e| panic!("{}", e));
+
+    let prog = command.wait_with_output().unwrap();
+    CmdResult {
+        success: prog.status.success(),
+        stdout: from_utf8(&prog.stdout).unwrap().to_string(),
+        stderr: from_utf8(&prog.stderr).unwrap().to_string(),
+    }
+}
+
+fn get_file_contents(name: &str) -> String {
+    let mut f = File::open(name).unwrap();
+    let mut contents = String::new();
+    let _ = f.read_to_string(&mut contents);
+    contents
+}
+
+macro_rules! assert_empty_stderr(
+    ($cond:expr) => (
+        if $cond.stderr.len() > 0 {
+            panic!(format!("stderr: {}", $cond.stderr))
+        }
+    );
+);
+
+macro_rules! get_hash(
+    ($str:expr) => (
+        $str.split(' ').collect::<Vec<&str>>()[0]
+    );
+);
+
+macro_rules! test_digest {
+    ($($t:ident)*) => ($(
+
+    mod $t {
+        use std::process::Command;
+
+        static DIGEST_ARG: &'static str = concat!("--", stringify!($t));
+        static EXPECTED_FILE: &'static str = concat!(stringify!($t), ".expected");
+
+        #[test]
+        fn test_single_file() {
+            let mut cmd = Command::new(::PROGNAME);
+            let result = ::run(&mut cmd.arg(DIGEST_ARG).arg("input.txt"));
+
+            assert_empty_stderr!(result);
+            assert!(result.success);
+            assert_eq!(get_hash!(result.stdout), ::get_file_contents(EXPECTED_FILE));
+        }
+
+        #[test]
+        fn test_stdin() {
+            let input = ::get_file_contents("input.txt");
+            let mut cmd = Command::new(::PROGNAME);
+            let result = ::run_piped_stdin(&mut cmd.arg(DIGEST_ARG), input.as_bytes());
+
+            assert_empty_stderr!(result);
+            assert!(result.success);
+            assert_eq!(get_hash!(result.stdout), ::get_file_contents(EXPECTED_FILE));
+        }
+    }
+    )*)
+}
+
+test_digest! { md5 sha1 sha224 sha256 sha384 sha512 }