1 files changed, 130 insertions, 2 deletions
diff --git a/tests/test_audio.py b/tests/test_audio.py
index 29bf4ea..f36ed54 100644
--- a/tests/test_audio.py
+++ b/tests/test_audio.py
@@ -1,11 +1,21 @@
-"""Tests for audio helpers: speed parameters, chunk cleanup, and encoding."""
+"""Tests for audio helpers: speed parameters, chunk cleanup, encoding,
+command construction, and duration verification."""
 
 import tempfile
 import unittest
 from pathlib import Path
 
+from converter import audio
 from converter import config
-from converter.audio import _encode_args, build_ffmetadata, cleanup_chunks, speed_export_params
+from converter.audio import (
+    _encode_args,
+    build_concat_command,
+    build_ffmetadata,
+    build_m4b_chapters_command,
+    cleanup_chunks,
+    speed_export_params,
+    verify_output_duration,
+)
 
 
 class SpeedExportParamsTests(unittest.TestCase):
@@ -76,6 +86,124 @@ class EncodeArgsTests(unittest.TestCase):
     def test_m4b_uses_aac(self):
         self.assertEqual(_encode_args("m4b"), ["-c:a", "aac", "-b:a", config.AUDIO_BITRATE])
 
+    def test_wav_is_lossless_pcm(self):
+        self.assertEqual(_encode_args("wav"), ["-c:a", "pcm_s16le"])
+
+
+class M4bContainerArgsTests(unittest.TestCase):
+    def setUp(self):
+        self._original = audio._brand_supported
+        audio._brand_supported = True
+
+    def tearDown(self):
+        audio._brand_supported = self._original
+
+    def test_includes_faststart_and_brand(self):
+        args = audio._m4b_container_args()
+        self.assertIn("+faststart", args)
+        self.assertIn("M4B ", args)
+
+    def test_brand_omitted_when_unsupported(self):
+        audio._brand_supported = False
+        self.assertEqual(audio._m4b_container_args(), ["-movflags", "+faststart"])
+
+
+class BuildConcatCommandTests(unittest.TestCase):
+    def setUp(self):
+        self._original = audio._brand_supported
+        audio._brand_supported = True
+
+    def tearDown(self):
+        audio._brand_supported = self._original
+
+    def test_mp3_has_no_container_flags(self):
+        cmd = build_concat_command(Path("list.txt"), Path("out.mp3"), "mp3")
+        self.assertEqual(cmd[:6], ["ffmpeg", "-y", "-f", "concat", "-safe", "0"])
+        self.assertNotIn("-movflags", cmd)
+        self.assertEqual(cmd[-1], "out.mp3")
+
+    def test_m4b_gets_faststart_and_brand(self):
+        cmd = build_concat_command(Path("list.txt"), Path("out.m4b"), "m4b")
+        self.assertIn("+faststart", cmd)
+        self.assertIn("M4B ", cmd)
+        self.assertEqual(cmd[-1], "out.m4b")
+
+    def test_speed_copy_writes_two_outputs(self):
+        cmd = build_concat_command(Path("list.txt"), Path("out.m4b"), "m4b",
+                                   speed=1.5, speed_path=Path("out_1.5.m4b"))
+        self.assertIn("out.m4b", cmd)
+        self.assertIn("out_1.5.m4b", cmd)
+        # faststart must apply to both outputs
+        self.assertEqual(cmd.count("+faststart"), 2)
+        self.assertTrue(any("atempo=1.5" in arg for arg in cmd))
+
+    def test_wav_intermediate(self):
+        cmd = build_concat_command(Path("list.txt"), Path("chapter.wav"), "wav")
+        self.assertIn("pcm_s16le", cmd)
+        self.assertNotIn("-movflags", cmd)
+
+
+class BuildM4bChaptersCommandTests(unittest.TestCase):
+    def setUp(self):
+        self._original = audio._brand_supported
+        audio._brand_supported = True
+
+    def tearDown(self):
+        audio._brand_supported = self._original
+
+    def test_base_output_maps_metadata_and_chapters(self):
+        cmd = build_m4b_chapters_command(Path("list.txt"), Path("meta.txt"), Path("out.m4b"))
+        self.assertIn("-map_metadata", cmd)
+        self.assertIn("-map_chapters", cmd)
+        self.assertIn("out.m4b", cmd)
+        self.assertIn("+faststart", cmd)
+        self.assertNotIn("filter_complex", cmd)
+
+    def test_speed_outputs_get_their_own_chapter_metadata(self):
+        cmd = build_m4b_chapters_command(
+            Path("list.txt"), Path("meta.txt"), Path("out.m4b"),
+            speed=2.0, speed_path=Path("out_2.m4b"), speed_metadata_file=Path("meta2.txt"),
+        )
+        self.assertEqual(cmd.count("+faststart"), 2)
+        self.assertEqual(cmd.count("-map_chapters"), 2)
+        self.assertTrue(any("atempo=2" in arg for arg in cmd))
+        # base output chapters come from metadata input 1, speed copy from 2
+        chapter_flags = [i for i, v in enumerate(cmd) if v == "-map_chapters"]
+        self.assertEqual(cmd[chapter_flags[0] + 1], "1")
+        self.assertEqual(cmd[chapter_flags[1] + 1], "2")
+        base_idx, speed_idx = cmd.index("out.m4b"), cmd.index("out_2.m4b")
+        self.assertLess(chapter_flags[0], base_idx)
+        self.assertGreater(chapter_flags[1], base_idx)
+        self.assertLess(chapter_flags[1], speed_idx)
+
+
+class VerifyOutputDurationTests(unittest.TestCase):
+    def _patch_probe(self, ms):
+        audio.probe_duration_ms = lambda path: ms
+
+    def setUp(self):
+        self._original_probe = audio.probe_duration_ms
+
+    def tearDown(self):
+        audio.probe_duration_ms = self._original_probe
+
+    def test_close_duration_passes(self):
+        self._patch_probe(100_000)
+        self.assertTrue(verify_output_duration(Path("x.m4b"), 101_000))
+
+    def test_unverifiable_duration_passes(self):
+        self._patch_probe(0)
+        self.assertTrue(verify_output_duration(Path("x.m4b"), 100_000))
+
+    def test_zero_expected_passes(self):
+        self._patch_probe(50_000)
+        self.assertTrue(verify_output_duration(Path("x.m4b"), 0))
+
+    def test_large_drift_fails(self):
+        self._patch_probe(3_600_000)  # bogus "1 hour" for a 1 minute book
+        with self.assertLogs(level="ERROR"):
+            self.assertFalse(verify_output_duration(Path("x.m4b"), 60_000))
+
 
 class BuildFFMetadataTests(unittest.TestCase):
     def test_writes_chapters(self):