From 440df36e7a3b69ff46bead20b1b30ac7e0c811e2 Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Fri, 22 Jul 2016 16:18:34 -0600
Subject: [PATCH] Improve failure mode in complexity_test.cc

---
 test/complexity_test.cc | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/test/complexity_test.cc b/test/complexity_test.cc
index 8ab88f97..6051f840 100644
--- a/test/complexity_test.cc
+++ b/test/complexity_test.cc
@@ -36,18 +36,27 @@ struct TestCase {
     CHECK(err_str.empty()) << "Could not construct regex \"" << regex << "\""
                            << " got Error: " << err_str;
 
+    std::string near = "<EOF>";
     std::string line;
+    bool first = true;
     while (remaining_output.eof() == false) {
         CHECK(remaining_output.good());
         std::getline(remaining_output, line);
+        // Keep the first line as context.
+        if (first) {
+            near = line;
+            first = false;
+        }
         if (r.Match(line)) return;
         CHECK(match_rule != MR_Next) << "Expected line \"" << line
-                                     << "\" to match regex \"" << regex << "\"";
+                                     << "\" to match regex \"" << regex << "\""
+                                     << "\nstarted matching at line: \"" << near << "\"";
     }
 
     CHECK(remaining_output.eof() == false)
         << "End of output reached before match for regex \"" << regex
-        << "\" was found";
+        << "\" was found"
+        << "\nstarted matching at line: \"" << near << "\"";
   }
 };