diff --git a/src/main/java/seedu/address/model/medicine/Quantity.java b/src/main/java/seedu/address/model/medicine/Quantity.java
index 8c089b07c824..961a89d9bc55 100644
--- a/src/main/java/seedu/address/model/medicine/Quantity.java
+++ b/src/main/java/seedu/address/model/medicine/Quantity.java
@@ -7,7 +7,7 @@
  * Represents the quantity of a Medicine in the inventory.
  * Guarantees: immutable; is valid as declared in {@link #isValidQuantity(String)}
  */
-public class Quantity {
+public class Quantity implements Comparable<Quantity> {
 
     public static final int MAX_QUANTITY = 1000000000;
     public static final int MIN_QUANTITY = 0;
@@ -60,6 +60,11 @@ public boolean equals(Object other) {
                 && value == ((Quantity) other).value); // state check
     }
 
+    @Override
+    public int compareTo(Quantity other) {
+        return Integer.compare(getNumericValue(), other.getNumericValue());
+    }
+
     @Override
     public int hashCode() {
         return this.toString().hashCode();
diff --git a/src/test/data/JsonSerializableInventoryTest/typicalMedicinesInventory.json b/src/test/data/JsonSerializableInventoryTest/typicalMedicinesInventory.json
index a71f4b00d8f9..e26c694adc26 100644
--- a/src/test/data/JsonSerializableInventoryTest/typicalMedicinesInventory.json
+++ b/src/test/data/JsonSerializableInventoryTest/typicalMedicinesInventory.json
@@ -33,6 +33,11 @@
         "batchNumber" : "GKP1685",
         "expiry" : "15/08/2019",
         "quantity" : "300"
+      },
+       {
+        "batchNumber" : "GKP1682",
+        "expiry" : "31/07/2019",
+        "quantity" : "5"
       } ]
   }, {
     "name" : "Lipitor",
diff --git a/src/test/java/seedu/address/logic/commands/UpdateCommandTest.java b/src/test/java/seedu/address/logic/commands/UpdateCommandTest.java
index 5c17a0f07999..6fac03b8856f 100644
--- a/src/test/java/seedu/address/logic/commands/UpdateCommandTest.java
+++ b/src/test/java/seedu/address/logic/commands/UpdateCommandTest.java
@@ -30,6 +30,7 @@
 import seedu.address.model.UserPrefs;
 import seedu.address.model.medicine.Batch;
 import seedu.address.model.medicine.BatchNumber;
+import seedu.address.model.medicine.Expiry;
 import seedu.address.model.medicine.Medicine;
 import seedu.address.model.medicine.Quantity;
 import seedu.address.testutil.BatchBuilder;
@@ -201,16 +202,17 @@ public void execute_removeBatchUnfilteredListOneOtherBatch_success() {
         Batch batchToRemove = iter.next();
 
         assertTrue(iter.hasNext()); // There is one more batch after removing
-        Batch batchRemaining = iter.next();
 
         batches.remove(batchToRemove.getBatchNumber());
 
         int newQuantity = medicineToUpdate.getTotalQuantity().getNumericValue()
                 - batchToRemove.getQuantity().getNumericValue();
 
+        Expiry newExpiry = batches.values().stream().min(Comparator.comparing(Batch::getExpiry)).get().getExpiry();
+
         Medicine updatedMedicine = new MedicineBuilder(medicineToUpdate)
                 .withQuantity(Integer.toString(newQuantity))
-                .withExpiry(batchRemaining.getExpiry().toString())
+                .withExpiry(newExpiry.toString())
                 .withBatches(batches).build();
 
         Batch inputBatch = new BatchBuilder(batchToRemove).withQuantity("0").build();
diff --git a/src/test/java/seedu/address/testutil/TypicalMedicines.java b/src/test/java/seedu/address/testutil/TypicalMedicines.java
index 941b1f7c4d08..2f5bcade196a 100644
--- a/src/test/java/seedu/address/testutil/TypicalMedicines.java
+++ b/src/test/java/seedu/address/testutil/TypicalMedicines.java
@@ -34,7 +34,8 @@ public class TypicalMedicines {
             .withQuantity("0").withExpiry("-").build();
     public static final Medicine LEVOTHYROXINE = new MedicineBuilder().withName("Levothyroxine Sodium")
             .withCompany("3M Pharmaceuticals").withQuantity("533").withExpiry("13/08/2019").withTags("thyroid")
-            .withBatches("GKP1684", "233", "13/08/2019", "GKP1685", "300", "15/08/2019").build();
+            .withBatches("GKP1684", "233", "13/08/2019", "GKP1685", "300", "15/08/2019", "GKP1682", "5", "31/07/2019")
+            .build();
     public static final Medicine LISINOPRIL = new MedicineBuilder().withName("Lisinopril")
             .withCompany("Takeda Pharmaceutical Co.").withQuantity("94").withExpiry("06/07/2019")
             .withBatches("307002", "94", "06/07/2019").build();
diff --git a/src/test/java/seedu/address/ui/InformationPanelTest.java b/src/test/java/seedu/address/ui/InformationPanelTest.java
index e561c28ae46b..72483c48ec3a 100644
--- a/src/test/java/seedu/address/ui/InformationPanelTest.java
+++ b/src/test/java/seedu/address/ui/InformationPanelTest.java
@@ -99,10 +99,10 @@ private void assertSorted(List<Batch> data, SortProperty sortProperty, SortDirec
             sortedData.sort(Comparator.comparing(b -> b.getBatchNumber().toString()));
             break;
         case EXPIRY:
-            sortedData.sort(Comparator.comparing(b -> b.getExpiry()));
+            sortedData.sort(Comparator.comparing(Batch::getExpiry));
             break;
         case QUANTITY:
-            sortedData.sort(Comparator.comparing(b -> b.getQuantity().getNumericValue()));
+            sortedData.sort(Comparator.comparing(Batch::getQuantity));
             break;
         default:
             throw new IllegalArgumentException("Unknown Sort Property");