restore << operator for mapnik::enumeration + add unit test

include/mapnik/enumeration.hpp

@@ -246,6 +246,16 @@ private:
     static bool  our_verified_flag_;
 };
 
+/** ostream operator for enumeration
+ * @relates mapnik::enumeration
+ */
+template <class ENUM, int THE_MAX>
+std::ostream &
+operator<<(std::ostream & os, const mapnik::enumeration<ENUM, THE_MAX> & e)
+{
+    return os << e.as_string();
+}
+
 } // end of namespace
 
 /** Helper macro.

test/unit/numerics/enumeration.cpp

@@ -0,0 +1,36 @@
+#include "catch.hpp"
+#include <mapnik/enumeration.hpp>
+#include <sstream>
+
+namespace mapnik {
+
+    enum _test_enumeration_enum : std::uint8_t
+    {
+        TEST_ONE,
+        TEST_TWO,
+        _test_enumeration_enum_MAX
+    };
+
+    DEFINE_ENUM( _test_enumeration_e, _test_enumeration_enum );
+
+    static const char * _test_enumeration_strings[] = {
+        "test_one",
+        "test_two",
+        ""
+    };
+
+    IMPLEMENT_ENUM( _test_enumeration_e, _test_enumeration_strings )
+
+}
+
+TEST_CASE("enumeration") {
+
+        mapnik::_test_enumeration_e e(mapnik::TEST_ONE);
+        CHECK( e.as_string() == "test_one" );
+        // test the << operator, which calls `as_string` internally
+        // this is not used in mapnik, but kept for back compat
+        std::stringstream s;
+        s << e;
+        CHECK( s.str() == "test_one" );
+
+}