killbill-memoizeit

diff --git a/invoice/src/main/java/org/killbill/billing/invoice/generator/InvoiceWithMetadata.java b/invoice/src/main/java/org/killbill/billing/invoice/generator/InvoiceWithMetadata.java
index ecb7c41..9425e0c 100644
--- a/invoice/src/main/java/org/killbill/billing/invoice/generator/InvoiceWithMetadata.java
+++ b/invoice/src/main/java/org/killbill/billing/invoice/generator/InvoiceWithMetadata.java
@@ -44,7 +44,6 @@ public class InvoiceWithMetadata {
         this.invoice = originalInvoice;
         this.perSubscriptionFutureNotificationDates = perSubscriptionFutureNotificationDates;
         build();
-        removeMarkerUsageItems();
     }
 
     public DefaultInvoice getInvoice() {
@@ -66,6 +65,9 @@ public class InvoiceWithMetadata {
                 tmp.resetNextRecurringDate();
             }
         }
+        if (invoice != null && invoice.getInvoiceItems().isEmpty()) {
+            invoice = null;
+        }
     }
 
     private boolean hasItemsForSubscription(final UUID subscriptionId, final InvoiceItemType invoiceItemType) {
@@ -78,32 +80,6 @@ public class InvoiceWithMetadata {
         });
     }
 
-    protected void removeMarkerUsageItems() {
-        if (invoice != null) {
-            final Iterator<InvoiceItem> it = invoice.getInvoiceItems().iterator();
-            while (it.hasNext()) {
-                final InvoiceItem item = it.next();
-                if (isMarkerUsageItem(item)) {
-                    it.remove();
-                }
-            }
-            if (invoice.getInvoiceItems().isEmpty()) {
-                invoice = null;
-            }
-        }
-    }
-
-    //
-    // $0 Usage item with no detail section
-    // ($0 Usage item *with* detail section are valid items in case of tiers defined with $0 amount)
-    //
-    private boolean isMarkerUsageItem(final InvoiceItem item) {
-        return item.getInvoiceItemType() == InvoiceItemType.USAGE &&
-               item.getItemDetails() == null &&
-               item.getAmount().compareTo(BigDecimal.ZERO) == 0;
-    }
-
-
     public static class SubscriptionFutureNotificationDates {
 
         private final BillingMode recurringBillingMode;

diff --git a/invoice/src/main/java/org/killbill/billing/invoice/usage/ContiguousIntervalUsageInArrear.java b/invoice/src/main/java/org/killbill/billing/invoice/usage/ContiguousIntervalUsageInArrear.java
index e4c0e08..f119913 100644
--- a/invoice/src/main/java/org/killbill/billing/invoice/usage/ContiguousIntervalUsageInArrear.java
+++ b/invoice/src/main/java/org/killbill/billing/invoice/usage/ContiguousIntervalUsageInArrear.java
@@ -170,19 +170,6 @@ public abstract class ContiguousIntervalUsageInArrear {
         }
 
         final List<InvoiceItem> result = Lists.newLinkedList();
-
-        // We start by generating 'marker' USAGE items with $0 that will allow to correctly insert the next notification for when there is no USAGE to bill.
-        // Those will be removed by the invoicing code later so as to not end up with superfluous $0 items
-        LocalDate prevDate = null;
-        for (final LocalDate curDate : transitionTimes) {
-            if (prevDate != null) {
-                final InvoiceItem item = new UsageInvoiceItem(invoiceId, accountId, getBundleId(), getSubscriptionId(), getProductName(), getPlanName(),
-                                                              getPhaseName(), usage.getName(), prevDate, curDate, BigDecimal.ZERO, getCurrency());
-                result.add(item);
-            }
-            prevDate = curDate;
-        }
-
         final List<RolledUpUsage> allUsage = getRolledUpUsage();
         // Each RolledUpUsage 'ru' is for a specific time period and across all units
         for (final RolledUpUsage ru : allUsage) {

diff --git a/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalCapacityInArrear.java b/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalCapacityInArrear.java
index bd4d5db..a87decb 100644
--- a/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalCapacityInArrear.java
+++ b/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalCapacityInArrear.java
@@ -213,15 +213,9 @@ public class TestContiguousIntervalCapacityInArrear extends TestUsageInArrearBas
         invoiceItems.add(ii2);
 
         final UsageInArrearItemsAndNextNotificationDate usageResult = intervalCapacityInArrear.computeMissingItemsAndNextNotificationDate(invoiceItems);
-        final List<InvoiceItem> rawResults = usageResult.getInvoiceItems();
-        assertEquals(rawResults.size(), 4);
+        final List<InvoiceItem> result = usageResult.getInvoiceItems();
+        assertEquals(result.size(), 2);
 
-        final List<InvoiceItem> result = ImmutableList.copyOf(Iterables.filter(rawResults, new Predicate<InvoiceItem>() {
-            @Override
-            public boolean apply(final InvoiceItem input) {
-                return input.getAmount().compareTo(BigDecimal.ZERO) > 0;
-            }
-        }));
 
         assertEquals(result.get(0).getAmount().compareTo(new BigDecimal("9.0")), 0, String.format("%s != 9.0", result.get(0).getAmount()));
         assertEquals(result.get(0).getCurrency(), Currency.BTC);

diff --git a/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalConsumableInArrear.java b/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalConsumableInArrear.java
index 87642cc..be5c8de 100644
--- a/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalConsumableInArrear.java
+++ b/invoice/src/test/java/org/killbill/billing/invoice/usage/TestContiguousIntervalConsumableInArrear.java
@@ -378,15 +378,9 @@ public class TestContiguousIntervalConsumableInArrear extends TestUsageInArrearB
         invoiceItems.add(ii2);
 
         final UsageInArrearItemsAndNextNotificationDate usageResult = intervalConsumableInArrear.computeMissingItemsAndNextNotificationDate(invoiceItems);
-        final List<InvoiceItem> rawResults = usageResult.getInvoiceItems();
-        assertEquals(rawResults.size(), 4);
+        final List<InvoiceItem> result = usageResult.getInvoiceItems();
+        assertEquals(result.size(), 2);
 
-        final List<InvoiceItem> result = ImmutableList.copyOf(Iterables.filter(rawResults, new Predicate<InvoiceItem>() {
-            @Override
-            public boolean apply(final InvoiceItem input) {
-                return input.getAmount().compareTo(BigDecimal.ZERO) > 0;
-            }
-        }));
 
         // Invoiced for 1 BTC and used 130 + 271 = 401 => 5 blocks => 5 BTC so remaining piece should be 4 BTC
         assertEquals(result.get(0).getAmount().compareTo(new BigDecimal("4.0")), 0, String.format("%s != 4.0", result.get(0).getAmount()));