diff --git a/test/paths_mac.cc b/test/paths_mac.cc
index ce6c5f3b..f3dca57a 100644
--- a/test/paths_mac.cc
+++ b/test/paths_mac.cc
@@ -27,7 +27,7 @@ base::FilePath Paths::Executable() {
   uint32_t executable_length = 0;
   _NSGetExecutablePath(nullptr, &executable_length);
   DCHECK_GT(executable_length, 1u);
-  std::string executable_path(executable_length, std::string::value_type());
+  std::string executable_path(executable_length - 1, std::string::value_type());
   int rv = _NSGetExecutablePath(&executable_path[0], &executable_length);
   DCHECK_EQ(rv, 0);