Merge pull request #1079 from shutefan/add-quiet-flag-to-tail

tail: suppress headers when --quiet flag is used

tests/fixtures/tail/foobar_multiple_quiet.expected

@@ -0,0 +1,12 @@
+dos
+tres
+quattro
+cinco
+seis
+siette
+ocho
+nueve
+diez
+once
+un
+deux

tests/test_tail.rs

@@ -245,3 +245,19 @@ fn test_lines_with_size_suffix() {
 
     ucmd.arg(FILE).arg("-n").arg("2K").run().stdout_is_fixture(EXPECTED_FILE);
 }
+
+#[test]
+fn test_multiple_input_files() {
+    new_ucmd!().arg(FOOBAR_TXT).arg(FOOBAR_2_TXT).run().stdout_is_fixture("foobar_follow_multiple.expected");
+}
+
+#[test]
+fn test_multiple_input_files_with_suppressed_headers() {
+    new_ucmd!().arg(FOOBAR_TXT).arg(FOOBAR_2_TXT).arg("-q").run().stdout_is_fixture("foobar_multiple_quiet.expected");
+}
+
+#[test]
+fn test_multiple_input_quiet_flag_overrides_verbose_flag_for_suppressing_headers() {
+    // TODO: actually the later one should win, i.e. -qv should lead to headers being printed, -vq to them being suppressed
+    new_ucmd!().arg(FOOBAR_TXT).arg(FOOBAR_2_TXT).arg("-q").arg("-v").run().stdout_is_fixture("foobar_multiple_quiet.expected");
+}