fen: simplify fen_check() + fix e.p. when no possible capture

test/common-test.h

@@ -393,6 +393,14 @@ struct fentest {
       "simple movedo/undo: only 2 W knights",
       "5n2/1k6/8/8/5K2/8/P7/1N6 w - - 0 1"
     },
+    { __LINE__, FEN,
+      "legal EP",
+      "4k3/8/8/3pP3/8/8/8/4K3 w - d6 0 1"
+    },
+    { __LINE__, FEN,
+      "illegal EP, fix-able by fen parser",
+      "4k3/8/8/3p1P2/8/8/8/4K3 w - d6 0 1"
+    },
     { __LINE__, FEN,
       "illegal EP and castle flags, fix-able by fen parser, SF crash",
       "4k3/8/8/8/7B/8/8/4K3 w KQkq e6 0 1"

test/fen-test.c

@@ -31,8 +31,7 @@ int main(__unused int ac, __unused char**av)
     bitboard_init();
 
     while ((fen = next_fen(FEN))) {
-        printf("***** [%s] ", fen);
-        fflush(stdout);
+        printf("line %3d: [%s] ", cur_line(), fen);
         if (!(pos = fen2pos(NULL, fen))) {
             printf("**INVALID\n");
         } else {

test/perft-test.c

@@ -287,7 +287,7 @@ int main(int __unused ac, __unused char**av)
     while ((fen = next_fen(PERFT | MOVEDO))) {
         test_line = cur_line();
         if (!(fenpos = fen2pos(pos, fen))) {
-            printf("wrong fen %d: [%s]\n", i, fen);
+            printf("wrong fen line = %d: [%s]\n", test_line, fen);
             continue;
         }
         pos = fenpos;