Fix clippy warnings in test code

Replace assert_eq! with literal bool, collapse nested if-let,
use iterators instead of indexed loops, use slice instead of vec.

src/mmp/algorithms.rs

@@ -475,7 +475,7 @@ mod tests {
 
         // Responder receives, copies bit
         responder.rx_observe(bit_to_send, 1, t0);
-        assert_eq!(responder.tx_bit(), false);
+        assert!(!responder.tx_bit());
 
         // Responder sends back, initiator receives
         let resp_bit = responder.tx_bit();
@@ -489,7 +489,7 @@ mod tests {
 
         // Responder receives new bit
         responder.rx_observe(bit2, 3, t1);
-        assert_eq!(responder.tx_bit(), true);
+        assert!(responder.tx_bit());
 
         // Responder sends back, initiator receives
         let resp_bit2 = responder.tx_bit();
@@ -504,10 +504,10 @@ mod tests {
 
         // Receive counter=5 with spin=true
         responder.rx_observe(true, 5, Instant::now());
-        assert_eq!(responder.tx_bit(), true);
+        assert!(responder.tx_bit());
 
         // Reordered packet with counter=3 and spin=false should be ignored
         responder.rx_observe(false, 3, Instant::now());
-        assert_eq!(responder.tx_bit(), true); // unchanged
+        assert!(responder.tx_bit()); // unchanged
     }
 }

src/node/tests/bloom.rs

@@ -269,19 +269,19 @@ fn print_filter_cardinality(nodes: &[TestNode]) {
                 continue;
             }
             let addr = *other.node.node_addr();
-            if let Some(peer) = tn.node.get_peer(&addr) {
-                if let Some(filter) = peer.inbound_filter() {
-                    let is_tree = tn.node.is_tree_peer(&addr);
-                    println!(
-                        "  n{} <- n{}: est={:.1} set_bits={} fill={:.1}% tree={}",
-                        i,
-                        j,
-                        filter.estimated_count(),
-                        filter.count_ones(),
-                        filter.fill_ratio() * 100.0,
-                        is_tree,
-                    );
-                }
+            if let Some(peer) = tn.node.get_peer(&addr)
+                && let Some(filter) = peer.inbound_filter()
+            {
+                let is_tree = tn.node.is_tree_peer(&addr);
+                println!(
+                    "  n{} <- n{}: est={:.1} set_bits={} fill={:.1}% tree={}",
+                    i,
+                    j,
+                    filter.estimated_count(),
+                    filter.count_ones(),
+                    filter.fill_ratio() * 100.0,
+                    is_tree,
+                );
             }
         }
     }

src/transport/tcp/mod.rs

@@ -840,8 +840,8 @@ mod tests {
         frame[1] = 0x00; // flags
         frame[2..4].copy_from_slice(&payload_len.to_le_bytes());
         // Fill the rest with a recognizable pattern
-        for i in 4..total {
-            frame[i] = (i & 0xFF) as u8;
+        for (i, byte) in frame[4..total].iter_mut().enumerate() {
+            *byte = ((4 + i) & 0xFF) as u8;
         }
 
         let bytes_sent = t1

src/transport/tcp/stream.rs

@@ -168,8 +168,8 @@ mod tests {
         frame[1] = 0x00; // flags
         frame[2..4].copy_from_slice(&payload_len.to_le_bytes());
         // Fill remaining with pattern for verification
-        for i in PREFIX_SIZE..total {
-            frame[i] = (i & 0xFF) as u8;
+        for (i, byte) in frame[PREFIX_SIZE..total].iter_mut().enumerate() {
+            *byte = ((PREFIX_SIZE + i) & 0xFF) as u8;
         }
         frame
     }
@@ -267,7 +267,7 @@ mod tests {
 
         // Provide enough bytes for the reader to read prefix
         let mut data = prefix.to_vec();
-        data.extend_from_slice(&vec![0u8; 200]); // extra bytes
+        data.extend_from_slice(&[0u8; 200]); // extra bytes
 
         let mut cursor = Cursor::new(data);
         let err = read_fmp_packet(&mut cursor, 100).await.unwrap_err();