test(client): split client tests into behavior-focused modules

crates/irtt-client/src/client/tests/negotiation.rs

@@ -0,0 +1,30 @@
+use super::*;
+
+#[test]
+fn strict_negotiation_accepts_identical_params() {
+    let config = ClientConfig::default();
+    let params = params_from_config(&config).unwrap();
+    assert!(validate_negotiated_params(&params, &params, NegotiationPolicy::Strict).is_ok());
+}
+
+#[test]
+fn strict_negotiation_rejects_changed_params() {
+    let config = ClientConfig::default();
+    let requested = params_from_config(&config).unwrap();
+    let mut returned = requested.clone();
+    returned.dscp = 1;
+    assert!(matches!(
+        validate_negotiated_params(&requested, &returned, NegotiationPolicy::Strict),
+        Err(ClientError::NegotiationRejected { .. })
+    ));
+}
+
+#[test]
+fn loose_negotiation_accepts_server_restricted_params() {
+    let config = ClientConfig::default();
+    let requested = params_from_config(&config).unwrap();
+    let mut returned = requested.clone();
+    returned.duration_ns /= 2;
+    returned.length = 0;
+    assert!(validate_negotiated_params(&requested, &returned, NegotiationPolicy::Loose).is_ok());
+}