FSTALIGN-63: Added an assert (#49)

Co-authored-by: Eugene Vignanker <[email protected]>

Author: eugenevignanker

src/fstalign.cpp

@@ -597,6 +597,7 @@ void write_stitches_to_nlp(vector<Stitching>& stitches, ofstream &output_nlp_fil
 
       ref_tk = original_nlp_token;
     } else if (stitch.comment.find("ins") == 0) {
+      assert(add_inserts);
       logger->debug("an insertion was found for {} {}", stitch.hyptk, stitch.comment);
       ref_tk = "";
       stitch.comment = "ins(" + stitch.hyptk + ")";