removes symphonia duration unit tests

In principle we do not have unit tests. See contributor guidlines for
the reasoning.

src/decoder/symphonia.rs

@@ -341,48 +341,3 @@ impl Iterator for SymphoniaDecoder {
         Some(sample)
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use std::time::Duration;
-
-    use symphonia::core::units::Time;
-
-    use crate::decoder::symphonia::time_to_duration;
-
-    #[test]
-    fn test_time_to_dur_zero_frac() {
-        let time = Time {
-            seconds: 7,
-            frac: 0.0,
-        };
-        let duration = Duration::new(
-            time.seconds,
-            if time.frac > 0.0 {
-                (1f64 / time.frac) as u32
-            } else {
-                0
-            },
-        );
-
-        assert_eq!(time_to_duration(time), duration);
-    }
-
-    #[test]
-    fn test_time_to_dur_non_zero_frac() {
-        let time = Time {
-            seconds: 7,
-            frac: 0.3,
-        };
-        let duration = Duration::new(
-            time.seconds,
-            if time.frac > 0.0 {
-                (1f64 / time.frac) as u32
-            } else {
-                0
-            },
-        );
-
-        assert_eq!(time_to_duration(time), duration);
-    }
-}