[librsvg: 4/8] rsvg-convert: Test that invalid language tags yield an error for --accept-language

[Federico Mena Quintero <federico src gnome org>]

commit a4c4824e16df662ec02c52a740803b669461e689
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Jul 7 15:04:35 2021 -0500

    rsvg-convert: Test that invalid language tags yield an error for --accept-language

 tests/src/cmdline/rsvg_convert.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/tests/src/cmdline/rsvg_convert.rs b/tests/src/cmdline/rsvg_convert.rs
index fa99bff1..726b20ef 100644
--- a/tests/src/cmdline/rsvg_convert.rs
+++ b/tests/src/cmdline/rsvg_convert.rs
@@ -849,6 +849,16 @@ fn accept_language_fallback() {
         );
 }
 
+#[test]
+fn accept_language_invalid_tag() {
+    // underscores are not valid in BCP47 language tags
+    RsvgConvert::new_with_input("tests/fixtures/cmdline/accept-language.svg")
+        .arg("--accept-language=foo_bar")
+        .assert()
+        .failure()
+        .stderr(contains("invalid language tag"));
+}
+
 #[test]
 fn keep_image_data_option() {
     RsvgConvert::accepts_arg("--keep-image-data");