diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 876886a..ca60e4b 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -18,6 +18,7 @@
 #include <cstdlib>
 #include <string_span.h>
 #include <vector>
+#include <map>
 
 using namespace std;
 using namespace gsl;
@@ -942,7 +943,13 @@ SUITE(string_span_tests)
                 CHECK(*(str + 3) == L'\0');
             }
         }
+    }
 
+    TEST(Issue305)
+    {
+        std::map<gsl::cstring_span<>, int> foo = { { "foo", 0 },{ "bar", 1 } };
+        CHECK(foo["foo"] == 0);
+        CHECK(foo["bar"] == 1);
     }
 }