gossipd/test: fix flaky test.

The test is could actually go each way, since for 1000000 the fee is
the same either way.

Increase to 300000, and add an extra test when the alternate path
is disabled.

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

gossipd/test/run-find_route.c

@@ -108,11 +108,19 @@ int main(void)
 	assert(fee == 0);
 
 	/* Will go via B for large amounts. */
-	nc = find_route(ctx, rstate, &a, &c, 1000000, 1.0, &fee, &route);
+	nc = find_route(ctx, rstate, &a, &c, 3000000, 1.0, &fee, &route);
 	assert(nc);
 	assert(tal_count(route) == 1);
 	assert(pubkey_eq(&route[0]->src->id, &b));
-	assert(fee == 2);
+	assert(fee == 1 + 3);
+
+	/* Make B->C inactive, force it back via D */
+	get_connection(rstate, &b, &c)->active = false;
+	nc = find_route(ctx, rstate, &a, &c, 3000000, 1.0, &fee, &route);
+	assert(nc);
+	assert(tal_count(route) == 1);
+	assert(pubkey_eq(&route[0]->src->id, &d));
+	assert(fee == 0 + 6);
 
 	tal_free(ctx);
 	return 0;