test/test_protocol: don't allow multiple commits in flight by default.

Add "nocommitwait" for the two cases we test that, otherwise add
assertions that we never end up dealing with anything other than
the previous commit.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

test/commits/05-two-commits-in-flight.script

@@ -1,4 +1,5 @@
 # Test committing before receiving previous revocation.
+A:nocommitwait
 A:offer 1
 A:commit
 A:offer 3

test/commits/15-fee-twice-back-to-back.script

@@ -1,4 +1,5 @@
 # Test committing fees before receiving previous revocation.
+A:nocommitwait
 A:feechange
 A:commit
 A:feechange

test/test_protocol.c

@@ -47,6 +47,9 @@ struct peer {
 	int infd, outfd, cmdfd, cmddonefd;
 
 	struct funding initial_funding;
+
+	/* Are we allowed to send another commit before receiving revoke? */
+	bool commitwait;
 	
 	/* Last one is the one we're changing. */
 	struct commit_info *us, *them;
@@ -286,9 +289,9 @@ static void send_feechange(struct peer *peer)
 	write_out(peer->outfd, "F", 1);
 }
 
-/* FIXME:
+/*
  * We don't enforce the rule that commits have to wait for revoke response
- * before the next one.  It might be simpler if we did?
+ * before the next one.
  */
 static struct commit_info *last_unrevoked(struct commit_info *ci)
 {
@@ -318,6 +321,10 @@ static void send_commit(struct peer *peer)
 	    && !peer->them->changes_outgoing)
 		errx(1, "commit: no changes to commit");
 
+	if (peer->commitwait
+	    && peer->them->prev && !peer->them->prev->revoked)
+		errx(1, "commit: must wait for previous commit");
+
 	peer->them = apply_changes(peer, peer->them);
 	sig = commit_sig(peer->them);
 	peer->them->counterparty_signed = true;
@@ -339,6 +346,11 @@ static void receive_revoke(struct peer *peer, u32 number)
 	if (ci->number != number)
 		errx(1, "receive_revoke: revoked %u but %u is next",
 		     number, ci->number);
+
+	/* This shouldn't happen if we don't allow multiple commits. */
+	if (peer->commitwait && ci != peer->them->prev)
+		errx(1, "receive_revoke: always revoke previous?");
+
 	ci->revoked = true;
 	if (!ci->counterparty_signed)
 		errx(1, "receive_revoke: revoked unsigned commit?");
@@ -470,6 +482,8 @@ static void do_cmd(struct peer *peer)
 		read_peer(peer, "C", cmd);
 		read_in(peer->infd, &sig, sizeof(sig));
 		receive_commit(peer, &sig);
+	} else if (streq(cmd, "nocommitwait")) {
+		peer->commitwait = false;
 	} else if (streq(cmd, "checksync")) {
 		write_all(peer->cmddonefd, peer->us->funding,
 			  sizeof(*peer->us->funding));
@@ -514,7 +528,8 @@ static void new_peer(int infdpair[2], int outfdpair[2], int cmdfdpair[2],
 
 	peer = tal(NULL, struct peer);
 	memset(&peer->initial_funding, 0, sizeof(peer->initial_funding));
-
+	peer->commitwait = true;
+	
 	/* Create first, signed commit info. */
 	peer->us = new_commit_info(peer, NULL);
 	peer->us->counterparty_signed = true;