test: make custom veilid network key opt-in in CI

Author: tripledoublev

.github/workflows/lint_and_test.yml

@@ -33,7 +33,6 @@ jobs:
         env:
           RUST_MIN_STACK: 8388608
           SAVE_VEILID_LOCAL_TEST_MODE: "1"
-          SAVE_VEILID_TEST_NETWORK_KEY: save-rust-ci-${{ github.run_id }}-${{ github.run_attempt }}
         # Retries configured in .config/nextest.toml (nextest default path)
         # --no-fail-fast: run all tests in this PR subset even when some fail.
         # Exclude long P2P network convergence tests from PR CI; run them in dedicated/nightly workflows.

src/lib.rs

@@ -97,9 +97,12 @@ mod tests {
             return;
         }
 
-        let network_key = env::var("SAVE_VEILID_TEST_NETWORK_KEY")
-            .unwrap_or_else(|_| "save-rust-local-test-network".to_string());
-        config.network.network_key_password = Some(network_key);
+        if let Ok(network_key) = env::var("SAVE_VEILID_TEST_NETWORK_KEY") {
+            let key = network_key.trim();
+            if !key.is_empty() {
+                config.network.network_key_password = Some(key.to_string());
+            }
+        }
 
         // Keep test nodes deterministic and less noisy in CI.
         config.network.upnp = false;