Added tests for last changes in requisition line items

Author: hassanhussein

src/main/java/org/openlmis/requisition/domain/requisition/LineItemFieldsCalculator.java

@@ -232,6 +232,11 @@ public static int calculateAverageConsumption(List<Integer> adjustedConsumptions
    */
   public static int calculateAverageConsumptionForCurrentMonth(
       Integer adjustedConsumption) {
+
+    if (adjustedConsumption == null) {
+      return 0;
+    }
+
     return (int) Math.ceil((adjustedConsumption) / 2.0);
   }
 

src/test/java/org/openlmis/requisition/domain/requisition/RequisitionLineItemTest.java

@@ -691,6 +691,56 @@ public void shouldCalculateStockBasedAverageConsumptionWithoutAdditionalQuantiti
     assertEquals(new Integer(51), item.getAverageConsumption());
   }
 
+  @Test
+  public void shouldCalculateAverageConsumptionForCurrentPeriodWithNonNullValue() {
+    // given
+    RequisitionLineItem item = new RequisitionLineItemDataBuilder()
+        .withAdjustedConsumption(10)
+        .build();
+
+    // when
+    item.calculateAndSetAverageConsumptionForCurrentPeriod();
+
+    // then
+    assertEquals(5, item.getAverageConsumption().intValue());
+  }
+
+  @Test
+  public void shouldCalculateAverageConsumptionForCurrentPeriodWithNullValue() {
+    // given
+    RequisitionLineItem item = new RequisitionLineItemDataBuilder()
+        .withAdjustedConsumption(null)
+        .build();
+    // when
+    item.calculateAndSetAverageConsumptionForCurrentPeriod();
+    // then
+    assertEquals(0, item.getAverageConsumption().intValue());
+  }
+
+  @Test
+  public void shouldCalculateAverageConsumptionForCurrentMonthWithEvenNumber() {
+    // when
+    int result = LineItemFieldsCalculator.calculateAverageConsumptionForCurrentMonth(10);
+    // then
+    assertEquals(5, result);
+  }
+
+  @Test
+  public void shouldCalculateAverageConsumptionForCurrentMonthWithOddNumber() {
+    // when
+    int result = LineItemFieldsCalculator.calculateAverageConsumptionForCurrentMonth(11);
+    // then
+    assertEquals(6, result);
+  }
+
+  @Test
+  public void shouldCalculateAverageConsumptionForCurrentMonthWithZero() {
+    // when
+    int result = LineItemFieldsCalculator.calculateAverageConsumptionForCurrentMonth(0);
+    // then
+    assertEquals(0, result);
+  }
+
   private void checkResultsOfConstruction(RequisitionLineItem item) {
     assertEquals(initiatedRequisition, item.getRequisition());
     assertEquals(orderableId, item.getOrderable().getId());