audio: open the output at the track's rate instead of pw-alsa's 44100

cpal asks the ALSA "default" PCM for its default config and pipewire-alsa
answers 44.1 kHz no matter what the graph runs at, so 48 kHz material was
resampled down to 44.1 in our linear resampler and then back up to 48 by
PipeWire. The stream now opens at the track's own rate (when the device
supports it), which keeps our resampler out of the path and leaves the
conversion to PipeWire's polyphase one.

The new `sample_rate` setting forces a fixed rate instead ("auto" by
default), for anyone who would rather match the graph exactly.

1 files changed, 42 insertions, 0 deletions

diff --git a/tests/config.rs b/tests/config.rs
index 7b9d179..6a44a17 100644
--- a/tests/config.rs
+++ b/tests/config.rs
@@ -21,6 +21,7 @@ fn test_config_get_scan_interval() {
         volume: None,
         shuffle: None,
         display_format: Some(String::from("$ARTIST - $TRACK")),
+        sample_rate: None,
     };
     assert_eq!(config.get("scan_interval").unwrap(), "3600");
 }
@@ -38,6 +39,7 @@ fn test_config_get_not_set() {
         volume: None,
         shuffle: None,
         display_format: None,
+        sample_rate: None,
     };
     assert_eq!(config.get("scan_interval").unwrap(), "not set");
 }
@@ -55,6 +57,7 @@ fn test_config_get_volume() {
         volume: Some(75),
         shuffle: None,
         display_format: None,
+        sample_rate: None,
     };
     assert_eq!(config.get("volume").unwrap(), "75");
 }
@@ -135,6 +138,7 @@ fn test_config_unset_volume() {
         volume: Some(50),
         shuffle: None,
         display_format: None,
+        sample_rate: None,
     };
     config.unset("volume").unwrap();
     assert_eq!(config.volume, None);
@@ -146,3 +150,41 @@ fn test_config_unset_unknown_key() {
     let result = config.unset("unknown_key");
     assert!(result.is_err());
 }
+
+#[test]
+fn test_config_sample_rate_defaults_to_auto() {
+    let config = Config {
+        config_path: PathBuf::from("/test/config.toml"),
+        music_paths: vec![],
+        scan_interval: None,
+        lastfm_api_key: None,
+        lastfm_api_secret: None,
+        lastfm_session_key: None,
+        listenbrainz_token: None,
+        volume: None,
+        shuffle: None,
+        display_format: None,
+        sample_rate: None,
+    };
+    assert_eq!(config.get("sample_rate").unwrap(), "auto");
+    assert_eq!(config.sample_rate_hz(), None);
+}
+
+#[test]
+fn test_config_set_sample_rate() {
+    let mut config = Config::default();
+    config.set("sample_rate", "48000").unwrap();
+    assert_eq!(config.get("sample_rate").unwrap(), "48000");
+    assert_eq!(config.sample_rate_hz(), Some(48_000));
+
+    config.set("sample_rate", "auto").unwrap();
+    assert_eq!(config.sample_rate_hz(), None);
+}
+
+#[test]
+fn test_config_rejects_bad_sample_rate() {
+    let mut config = Config::default();
+    assert!(config.set("sample_rate", "fast").is_err());
+    assert!(config.set("sample_rate", "100").is_err());
+    assert!(config.set("sample_rate", "999999").is_err());
+}