1 files changed, 30 insertions, 0 deletions
diff --git a/app/tests/test_audio.py b/app/tests/test_audio.py
index 75de97c..04a6afc 100644
--- a/app/tests/test_audio.py
+++ b/app/tests/test_audio.py
@@ -51,6 +51,36 @@ class AtempoFiltersTests(unittest.TestCase):
         with self.assertRaises(ValueError):
             atempo_filters(-1.5)
 
+    def test_infinite_speed_rejected(self):
+        # inf passes a bare positivity check; without the finite guard
+        # atempo chaining would loop forever (inf / 2.0 stays inf).
+        with self.assertRaises(ValueError):
+            atempo_filters(float("inf"))
+
+    def test_overflowing_speed_rejected(self):
+        with self.assertRaises(ValueError):
+            atempo_filters(1e309)
+
+    def test_nan_speed_rejected(self):
+        with self.assertRaises(ValueError):
+            atempo_filters(float("nan"))
+
+    def test_asplit_used_for_audio_streams(self):
+        # split is a video filter and rejects an audio stream, so a
+        # speed-adjusted copy needs asplit — in both command builders.
+        concat_cmd = build_concat_command(
+            Path("/tmp/_concat.txt"), Path("/tmp/out.mp3"), "mp3",
+            speed=1.5, speed_path=Path("/tmp/out_1.5.mp3"))
+        m4b_cmd = build_m4b_chapters_command(
+            Path("/tmp/_concat.txt"), Path("/tmp/_meta.txt"),
+            Path("/tmp/out.m4b"), speed=1.5,
+            speed_path=Path("/tmp/out_1.5.m4b"),
+            speed_metadata_file=Path("/tmp/_meta2.txt"))
+        for cmd in (concat_cmd, m4b_cmd):
+            filter_complex = cmd[cmd.index("-filter_complex") + 1]
+            self.assertIn("[0:a]asplit=2", filter_complex)
+            self.assertNotIn("[0:a]split=2", filter_complex)
+
 
 class CleanupChunksTests(unittest.TestCase):
     def test_removes_only_chunk_files(self):