diff --git a/src/main.rs b/src/main.rs
index ecc1d9c..3640662 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1480,7 +1480,7 @@ fn main() {
 
 #[cfg(test)]
 mod tests {
-    use super::find_urls;
+    use super::{base64_encode, find_urls};
     use crate::terminal::TerminalState;
 
     /// Write `text` into row 0 of a freshly-created state.
@@ -1622,4 +1622,55 @@ mod tests {
         let u = "https://example.com/path?q=1&r=2#frag";
         assert_eq!(urls(u), vec![u]);
     }
+
+    // ── base64_encode ─────────────────────────────────────────────────────────
+
+    #[test]
+    fn base64_empty() {
+        assert_eq!(base64_encode(b""), "");
+    }
+
+    #[test]
+    fn base64_well_known_vectors() {
+        // RFC 4648 test vectors
+        assert_eq!(base64_encode(b"f"), "Zg==");
+        assert_eq!(base64_encode(b"fo"), "Zm8=");
+        assert_eq!(base64_encode(b"foo"), "Zm9v");
+        assert_eq!(base64_encode(b"foob"), "Zm9vYg==");
+        assert_eq!(base64_encode(b"fooba"), "Zm9vYmE=");
+        assert_eq!(base64_encode(b"foobar"), "Zm9vYmFy");
+    }
+
+    #[test]
+    fn base64_hello() {
+        assert_eq!(base64_encode(b"hello"), "aGVsbG8=");
+    }
+
+    #[test]
+    fn base64_all_zeros() {
+        assert_eq!(base64_encode(&[0u8; 3]), "AAAA");
+    }
+
+    #[test]
+    fn base64_output_length_always_multiple_of_four() {
+        for len in 0..=9 {
+            let data = vec![0xffu8; len];
+            let encoded = base64_encode(&data);
+            assert_eq!(encoded.len() % 4, 0, "length {len} → encoded len {}", encoded.len());
+        }
+    }
+
+    #[test]
+    fn base64_padding_one_equals() {
+        // 2-byte input → 3 output chars + 1 '='
+        let enc = base64_encode(b"ab");
+        assert!(enc.ends_with('=') && !enc.ends_with("=="), "got: {enc}");
+    }
+
+    #[test]
+    fn base64_padding_two_equals() {
+        // 1-byte input → 2 output chars + "=="
+        let enc = base64_encode(b"a");
+        assert!(enc.ends_with("=="), "got: {enc}");
+    }
 }
diff --git a/src/terminal.rs b/src/terminal.rs
index 97a219e..2e0f6d7 100644
--- a/src/terminal.rs
+++ b/src/terminal.rs
@@ -1232,6 +1232,71 @@ mod tests {
         t.process(LEAVE_ALT);
         assert_eq!(ch(&t, 0, 0), 'C'); // normal content restored
     }
+
+    // ── Bracketed paste mode ──────────────────────────────────────────────────
+
+    #[test]
+    fn bracketed_paste_enabled_by_2004h() {
+        let mut t = t(80, 24);
+        assert!(!t.state.bracketed_paste);
+        t.process(b"\x1b[?2004h");
+        assert!(t.state.bracketed_paste);
+    }
+
+    #[test]
+    fn bracketed_paste_disabled_by_2004l() {
+        let mut t = t(80, 24);
+        t.process(b"\x1b[?2004h");
+        t.process(b"\x1b[?2004l");
+        assert!(!t.state.bracketed_paste);
+    }
+
+    #[test]
+    fn bracketed_paste_toggle_independent_of_alt_screen() {
+        let mut t = t(80, 24);
+        t.process(b"\x1b[?2004h");
+        t.process(ENTER_ALT);
+        assert!(t.state.bracketed_paste);
+        t.process(LEAVE_ALT);
+        assert!(t.state.bracketed_paste);
+    }
+
+    // ── OSC 52 clipboard query ────────────────────────────────────────────────
+
+    #[test]
+    fn osc_52_query_sets_flag() {
+        let mut t = t(80, 24);
+        assert!(!t.state.osc_52_query);
+        // vte splits OSC params on ';', so params will be ["52", "c", "?"]
+        t.process(b"\x1b]52;c;?\x07");
+        assert!(t.state.osc_52_query);
+    }
+
+    #[test]
+    fn osc_52_query_flag_via_dispatch() {
+        // Direct osc_dispatch call — isolates parsing from vte.
+        let mut s = TerminalState::new(80, 24);
+        s.osc_dispatch(&[b"52", b"c", b"?"], false);
+        assert!(s.osc_52_query);
+    }
+
+    #[test]
+    fn osc_52_non_query_does_not_set_flag() {
+        let mut s = TerminalState::new(80, 24);
+        // A write (non-"?") payload must not set the query flag.
+        s.osc_dispatch(&[b"52", b"c", b"aGVsbG8="], false);
+        assert!(!s.osc_52_query);
+    }
+
+    #[test]
+    fn osc_52_query_flag_cleared_externally() {
+        let mut t = t(80, 24);
+        t.process(b"\x1b]52;c;?\x07");
+        assert!(t.state.osc_52_query);
+        // Simulate host clearing the flag after responding.
+        t.state.osc_52_query = false;
+        assert!(!t.state.osc_52_query);
+    }
 }
 
 pub struct Terminal {