cksum: add tests and fixtures (#1923)

tests/by-util/test_cksum.rs

@@ -24,3 +24,79 @@ fn test_stdin() {
         .succeeds()
         .stdout_is_fixture("stdin.expected");
 }
+
+#[test]
+fn test_empty() {
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    at.touch("a");
+
+    ucmd.arg("a").succeeds().stdout.ends_with("0 a");
+}
+
+#[test]
+fn test_arg_overrides_stdin() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let input = "foobarfoobar";
+
+    at.touch("a");
+
+    let result = ucmd.arg("a").pipe_in(input.as_bytes()).run();
+
+    println!("{}, {}", result.stdout, result.stderr);
+
+    assert!(result.stdout.ends_with("0 a\n"))
+}
+
+#[test]
+fn test_invalid_file() {
+    let (_, mut ucmd) = at_and_ucmd!();
+
+    let ls = TestScenario::new("ls");
+    let files = ls.cmd("ls").arg("-l").run();
+    println!("{:?}", files.stdout);
+    println!("{:?}", files.stderr);
+
+    let folder_name = "asdf".to_string();
+
+    let result = ucmd.arg(&folder_name).run();
+
+    println!("stdout: {:?}", result.stdout);
+    println!("stderr: {:?}", result.stderr);
+    assert!(result.stderr.contains("cksum: error: 'asdf'"));
+    assert!(!result.success);
+}
+
+// Make sure crc is correct for files larger than 32 bytes
+// but <128 bytes (1 fold pclmul)
+#[test]
+fn test_crc_for_bigger_than_32_bytes() {
+    let (_, mut ucmd) = at_and_ucmd!();
+
+    let result = ucmd.arg("chars.txt").run();
+
+    let mut stdout_splitted = result.stdout.split(" ");
+
+    let cksum: i64 = stdout_splitted.next().unwrap().parse().unwrap();
+    let bytes_cnt: i64 = stdout_splitted.next().unwrap().parse().unwrap();
+
+    assert!(result.success);
+    assert_eq!(cksum, 586047089);
+    assert_eq!(bytes_cnt, 16);
+}
+
+#[test]
+fn test_stdin_larger_than_128_bytes() {
+    let (_, mut ucmd) = at_and_ucmd!();
+
+    let result = ucmd.arg("larger_than_2056_bytes.txt").run();
+
+    let mut stdout_splitted = result.stdout.split(" ");
+
+    let cksum: i64 = stdout_splitted.next().unwrap().parse().unwrap();
+    let bytes_cnt: i64 = stdout_splitted.next().unwrap().parse().unwrap();
+
+    assert!(result.success);
+    assert_eq!(cksum, 945881979);
+    assert_eq!(bytes_cnt, 2058);
+}