diff --git a/agent/src/main.rs b/agent/src/main.rs
index b85af26..e93f9ca 100644
--- a/agent/src/main.rs
+++ b/agent/src/main.rs
@@ -223,6 +223,16 @@ mod tests {
     use serde_cbor::de::Deserializer;
     use std::path::Path;
 
+    // This test assumes input.cborseq (trace file) and output.cborseq
+    // (log file) in $CARGO_MANIFEST_DIR/../fixtures/normal.  These
+    // files can be generated by exercising the GnuTLS session after
+    // starting up the agent with:
+    //
+    //   sudo target/debug/crypto-auditing-agent -c agent/fixtures/agent.conf \
+    //        --library /usr/lib64/libgnutls.so.30 --user $USER:$GID \
+    //        --trace-file fixtures/normal/input.cborseq \
+    //        --log-file fixtures/normal/output.cborseq
+    //
     #[test]
     fn test_normal() {
         let fixtures_path = Path::new(env!("CARGO_MANIFEST_DIR"))