[fix](trx-backend): fix clippy warnings and improve code style

Fix useless vec! allocation in demod tests, improve loop iterator usage,
and reformat code for better readability across dummy and soapysdr
backends.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/trx-server/trx-backend/src/dummy.rs

@@ -157,21 +157,33 @@ mod tests {
         let caps = &rig.info().capabilities;
         assert!(caps.tx, "dummy rig should have tx capability");
         assert!(caps.tx_limit, "dummy rig should have tx_limit capability");
-        assert!(caps.vfo_switch, "dummy rig should have vfo_switch capability");
+        assert!(
-        assert!(caps.signal_meter, "dummy rig should have signal_meter capability");
+            caps.vfo_switch,
+            "dummy rig should have vfo_switch capability"
+        );
+        assert!(
+            caps.signal_meter,
+            "dummy rig should have signal_meter capability"
+        );
     }
 
     #[test]
     fn dummy_has_no_filter_controls() {
         let rig = DummyRig::new();
         let caps = &rig.info().capabilities;
-        assert!(!caps.filter_controls, "dummy rig should not have filter_controls");
+        assert!(
+            !caps.filter_controls,
+            "dummy rig should not have filter_controls"
+        );
     }
 
     #[test]
     fn dummy_filter_state_is_none() {
         let rig = DummyRig::new();
-        assert!(rig.filter_state().is_none(), "dummy rig should return None for filter_state");
+        assert!(
+            rig.filter_state().is_none(),
+            "dummy rig should return None for filter_state"
+        );
     }
 }
 

src/trx-server/trx-backend/trx-backend-soapysdr/src/demod.rs

@@ -94,11 +94,7 @@ fn demod_am(samples: &[Complex<f32>]) -> Vec<f32> {
     let mut output: Vec<f32> = mag.iter().map(|&m| m - mean).collect();
 
     // Normalise peak to ≤ 1.0 (only if max > 1.0, to avoid amplifying noise).
-    let max_abs = output
+    let max_abs = output.iter().copied().map(f32::abs).fold(0.0_f32, f32::max);
-        .iter()
-        .copied()
-        .map(f32::abs)
-        .fold(0.0_f32, f32::max);
     if max_abs > 1.0 {
         let inv = 1.0 / max_abs;
         for sample in &mut output {
@@ -241,7 +237,7 @@ mod tests {
             Complex::new(0.0, 0.0),
             Complex::new(1.0, 0.0),
         ];
-        let expected = vec![-0.5_f32, 0.5, -0.5, 0.5];
+        let expected = [-0.5_f32, 0.5, -0.5, 0.5];
         let out = Demodulator::Am.demodulate(&input);
         assert_eq!(out.len(), 4);
         for (i, (&got, &exp)) in out.iter().zip(expected.iter()).enumerate() {
@@ -259,8 +255,8 @@ mod tests {
         // First sample is 0.0 by convention.
         assert_approx_eq(out[0], 0.0, 1e-6, "FM tone sample 0 (zero by convention)");
         // Remaining samples should be approximately 0.5.
-        for i in 1..out.len() {
+        for (i, &sample) in out.iter().enumerate().skip(1) {
-            assert_approx_eq(out[i], 0.5, 0.01, &format!("FM tone sample {}", i));
+            assert_approx_eq(sample, 0.5, 0.01, &format!("FM tone sample {}", i));
         }
     }
 
@@ -300,8 +296,14 @@ mod tests {
         assert_eq!(Demodulator::for_mode(&RigMode::WFM), Demodulator::Wfm);
         assert_eq!(Demodulator::for_mode(&RigMode::CW), Demodulator::Cw);
         assert_eq!(Demodulator::for_mode(&RigMode::CWR), Demodulator::Cw);
-        assert_eq!(Demodulator::for_mode(&RigMode::DIG), Demodulator::Passthrough);
+        assert_eq!(
-        assert_eq!(Demodulator::for_mode(&RigMode::PKT), Demodulator::Passthrough);
+            Demodulator::for_mode(&RigMode::DIG),
+            Demodulator::Passthrough
+        );
+        assert_eq!(
+            Demodulator::for_mode(&RigMode::PKT),
+            Demodulator::Passthrough
+        );
     }
 
     // Test 9: All demodulators return an empty Vec for empty input without panicking.

src/trx-server/trx-backend/trx-backend-soapysdr/src/dsp.rs

@@ -321,8 +321,7 @@ impl SdrPipeline {
     ) -> Self {
         // Broadcast channel capacity: 64 IQ blocks.
         const IQ_BROADCAST_CAPACITY: usize = 64;
-        let (iq_tx, _iq_rx) =
+        let (iq_tx, _iq_rx) = broadcast::channel::<Vec<Complex<f32>>>(IQ_BROADCAST_CAPACITY);
-            broadcast::channel::<Vec<Complex<f32>>>(IQ_BROADCAST_CAPACITY);
 
         // PCM broadcast capacity: enough for several frames of latency.
         const PCM_BROADCAST_CAPACITY: usize = 32;
@@ -468,13 +467,13 @@ mod tests {
     fn channel_dsp_processes_silence() {
         let (pcm_tx, _pcm_rx) = broadcast::channel::<Vec<f32>>(8);
         let mut dsp = ChannelDsp::new(
-            0.0,       // channel_if_hz
+            0.0, // channel_if_hz
             &RigMode::USB,
-            48_000,    // sdr_sample_rate
+            48_000, // sdr_sample_rate
-            8_000,     // audio_sample_rate  (decim = 6)
+            8_000,  // audio_sample_rate  (decim = 6)
-            20,        // frame_duration_ms → frame_size = 160
+            20,     // frame_duration_ms → frame_size = 160
-            3000,      // audio_bandwidth_hz
+            3000,   // audio_bandwidth_hz
-            31,        // fir_taps
+            31,     // fir_taps
             pcm_tx,
         );
 
@@ -486,16 +485,7 @@ mod tests {
     #[test]
     fn channel_dsp_set_mode() {
         let (pcm_tx, _) = broadcast::channel::<Vec<f32>>(8);
-        let mut dsp = ChannelDsp::new(
+        let mut dsp = ChannelDsp::new(0.0, &RigMode::USB, 48_000, 8_000, 20, 3000, 31, pcm_tx);
-            0.0,
-            &RigMode::USB,
-            48_000,
-            8_000,
-            20,
-            3000,
-            31,
-            pcm_tx,
-        );
         assert_eq!(dsp.demodulator, Demodulator::Usb);
         dsp.set_mode(&RigMode::FM);
         assert_eq!(dsp.demodulator, Demodulator::Fm);
@@ -516,13 +506,7 @@ mod tests {
 
     #[test]
     fn pipeline_empty_channels() {
-        let pipeline = SdrPipeline::start(
+        let pipeline = SdrPipeline::start(Box::new(MockIqSource), 1_920_000, 48_000, 20, &[]);
-            Box::new(MockIqSource),
-            1_920_000,
-            48_000,
-            20,
-            &[],
-        );
         assert_eq!(pipeline.pcm_senders.len(), 0);
         assert_eq!(pipeline.channel_dsps.len(), 0);
     }

src/trx-server/trx-backend/trx-backend-soapysdr/src/lib.rs

@@ -8,11 +8,11 @@ pub mod dsp;
 use std::pin::Pin;
 
 use trx_core::radio::freq::{Band, Freq};
+use trx_core::rig::response::RigError;
+use trx_core::rig::state::RigFilterState;
 use trx_core::rig::{
     AudioSource, Rig, RigAccessMethod, RigCapabilities, RigCat, RigInfo, RigStatusFuture,
 };
-use trx_core::rig::response::RigError;
-use trx_core::rig::state::RigFilterState;
 use trx_core::{DynResult, RigMode};
 
 /// RX-only backend for any SoapySDR-compatible device.