Introduce increaseTimeTo helper method.

test/helpers/increaseTime.js

@@ -1,4 +1,6 @@
-// Increases testrpc time by the passed duration (a moment.js instance)
+import latestTime from './latestTime'
+
+// Increases testrpc time by the passed duration in seconds
 export default function increaseTime(duration) {
   const id = Date.now()
 
@@ -22,12 +24,24 @@ export default function increaseTime(duration) {
   })
 }
 
+/**
+ * Beware that due to the need of calling two separate testrpc methods and rpc calls overhead
+ * it's hard to increase time precisely to a target point so design your test to tolerate
+ * small fluctuations from time to time.
+ *
+ * @param target time in seconds
+ */
+export function increaseTimeTo(target) {
+  let now = latestTime().unix();
+  if (target < now) throw Error(`Cannot increase current time(${now}) to a moment in the past(${target})`);
+  let diff = target - now;
+  return increaseTime(diff);
+}
+
 export const duration = {
   seconds: function(val) { return val},
   minutes: function(val) { return val * this.seconds(60) },
   hours:   function(val) { return val * this.minutes(60) },
   days:    function(val) { return val * this.hours(24) },
   weeks:   function(val) { return val * this.days(7) }
-};
-
-export const increaseTimeHandicap = duration.seconds(10);
+};