Progress bitshares#1604: Do not allow sooner expiration

Updating an order's expiration must make it expire later than before,
not the same or sooner.

Author: nathanielhourt

libraries/chain/market_evaluator.cpp

@@ -177,8 +177,8 @@ void_result limit_order_update_evaluator::do_evaluate(const limit_order_update_o
 
    // Check expiration is in the future
    if (o.new_expiration)
-      FC_ASSERT(*o.new_expiration >= d.head_block_time(),
-                "Cannot update limit order with past expiration");
+      FC_ASSERT(*o.new_expiration > _order->expiration,
+                "Cannot update limit order to expire sooner; new expiration must be later than old one.");
 
    return {};
 } FC_CAPTURE_AND_RETHROW((o)) }

tests/tests/operation_tests.cpp

@@ -148,9 +148,11 @@ BOOST_AUTO_TEST_CASE(limit_order_update_test)
       expiration += 50;
       update_limit_order(order_id, {}, {}, expiration);
       BOOST_REQUIRE_EQUAL(order_id(db).expiration.sec_since_epoch(), expiration.sec_since_epoch());
-      expiration -= 100;
-      update_limit_order(order_id, {}, {}, expiration);
-      BOOST_REQUIRE_EQUAL(order_id(db).expiration.sec_since_epoch(), expiration.sec_since_epoch());
+      // Cannot make expiration same as before
+      GRAPHENE_REQUIRE_THROW(update_limit_order(order_id, {}, {}, expiration), fc::assert_exception);
+      // Cannot make expiration sooner; only later
+      GRAPHENE_REQUIRE_THROW(update_limit_order(order_id, {}, {}, expiration - 100), fc::assert_exception);
+      GRAPHENE_REQUIRE_THROW(update_limit_order(order_id, {}, {}, expiration - 1), fc::assert_exception);
 
       // Try adding funds
       update_limit_order(order_id, {}, asset(50));