1 files changed, 69 insertions, 0 deletions
diff --git a/third_party/rust/regex-automata/tests/dfa/api.rs b/third_party/rust/regex-automata/tests/dfa/api.rs
new file mode 100644
index 0000000000..96e73af6c2
--- /dev/null
+++ b/third_party/rust/regex-automata/tests/dfa/api.rs
@@ -0,0 +1,69 @@
+use std::error::Error;
+
+use regex_automata::{
+    dfa::{dense, Automaton, OverlappingState},
+    nfa::thompson,
+    HalfMatch, Input, MatchError,
+};
+
+// Tests that quit bytes in the forward direction work correctly.
+#[test]
+fn quit_fwd() -> Result<(), Box<dyn Error>> {
+    let dfa = dense::Builder::new()
+        .configure(dense::Config::new().quit(b'x', true))
+        .build("[[:word:]]+$")?;
+
+    assert_eq!(
+        Err(MatchError::quit(b'x', 3)),
+        dfa.try_search_fwd(&Input::new(b"abcxyz"))
+    );
+    assert_eq!(
+        dfa.try_search_overlapping_fwd(
+            &Input::new(b"abcxyz"),
+            &mut OverlappingState::start()
+        ),
+        Err(MatchError::quit(b'x', 3)),
+    );
+
+    Ok(())
+}
+
+// Tests that quit bytes in the reverse direction work correctly.
+#[test]
+fn quit_rev() -> Result<(), Box<dyn Error>> {
+    let dfa = dense::Builder::new()
+        .configure(dense::Config::new().quit(b'x', true))
+        .thompson(thompson::Config::new().reverse(true))
+        .build("^[[:word:]]+")?;
+
+    assert_eq!(
+        Err(MatchError::quit(b'x', 3)),
+        dfa.try_search_rev(&Input::new(b"abcxyz"))
+    );
+
+    Ok(())
+}
+
+// Tests that if we heuristically enable Unicode word boundaries but then
+// instruct that a non-ASCII byte should NOT be a quit byte, then the builder
+// will panic.
+#[test]
+#[should_panic]
+fn quit_panics() {
+    dense::Config::new().unicode_word_boundary(true).quit(b'\xFF', false);
+}
+
+// This tests an intesting case where even if the Unicode word boundary option
+// is disabled, setting all non-ASCII bytes to be quit bytes will cause Unicode
+// word boundaries to be enabled.
+#[test]
+fn unicode_word_implicitly_works() -> Result<(), Box<dyn Error>> {
+    let mut config = dense::Config::new();
+    for b in 0x80..=0xFF {
+        config = config.quit(b, true);
+    }
+    let dfa = dense::Builder::new().configure(config).build(r"\b")?;
+    let expected = HalfMatch::must(0, 1);
+    assert_eq!(Ok(Some(expected)), dfa.try_search_fwd(&Input::new(b" a")));
+    Ok(())
+}