typo

tests/datadriven.cpp

@@ -110,7 +110,7 @@ void test_one_item_actual(const compare_test& c)
 							<< fields[0] << " on line " << line_no);
 					} else if (v->to_string(tagset) != fields[1]) {
 						BOOST_ERROR("Variable " << fields[0]
-							<< "value mismatch on line "
+							<< " value mismatch on line "
 							<< line_no << "\n: expected " << fields[1]
 							<< " got " << v->to_string(tagset));
 					}