Fix delete behavior in Cosmos adapter (#2341)

Author: brfrn169

core/src/main/java/com/scalar/db/storage/cosmos/DeleteStatementHandler.java

@@ -2,6 +2,7 @@
 
 import com.azure.cosmos.CosmosClient;
 import com.azure.cosmos.CosmosException;
+import com.azure.cosmos.implementation.NotFoundException;
 import com.azure.cosmos.models.CosmosItemRequestOptions;
 import com.azure.cosmos.models.PartitionKey;
 import com.scalar.db.api.Delete;
@@ -42,7 +43,11 @@ private void execute(Mutation mutation, TableMetadata tableMetadata) throws Cosm
       PartitionKey partitionKey = cosmosMutation.getCosmosPartitionKey();
       CosmosItemRequestOptions options = new CosmosItemRequestOptions();
 
-      getContainer(mutation).deleteItem(id, partitionKey, options);
+      try {
+        getContainer(mutation).deleteItem(id, partitionKey, options);
+      } catch (NotFoundException ignored) {
+        // don't throw an exception if the item is not found
+      }
     } else {
       // clustering key is not fully specified
       executeStoredProcedure(mutation, tableMetadata);

core/src/test/java/com/scalar/db/storage/cosmos/DeleteStatementHandlerTest.java

@@ -18,6 +18,7 @@
 import com.azure.cosmos.CosmosException;
 import com.azure.cosmos.CosmosScripts;
 import com.azure.cosmos.CosmosStoredProcedure;
+import com.azure.cosmos.implementation.NotFoundException;
 import com.azure.cosmos.models.CosmosItemRequestOptions;
 import com.azure.cosmos.models.CosmosItemResponse;
 import com.azure.cosmos.models.CosmosStoredProcedureRequestOptions;
@@ -121,6 +122,19 @@ public void handle_DeleteWithoutConditionsCosmosExceptionThrown_ShouldThrowExecu
         .hasCause(toThrow);
   }
 
+  @Test
+  public void handle_DeleteWithoutConditionsNotFoundExceptionThrown_ShouldNotThrowAnyException() {
+    // Arrange
+    doThrow(NotFoundException.class)
+        .when(container)
+        .deleteItem(anyString(), any(PartitionKey.class), any(CosmosItemRequestOptions.class));
+
+    Delete delete = prepareDelete();
+
+    // Act Assert
+    assertThatCode(() -> handler.handle(delete)).doesNotThrowAnyException();
+  }
+
   @Test
   public void handle_DeleteWithoutClusteringKeyGiven_ShouldCallStoredProcedure() {
     // Arrange

integration-test/src/main/java/com/scalar/db/api/DistributedStorageIntegrationTestBase.java

@@ -1499,6 +1499,17 @@ public void delete_MultipleDeleteWithDifferentConditionsGiven_ShouldDeleteProper
     assertThat(results.size()).isEqualTo(0);
   }
 
+  @Test
+  public void delete_ForNonExistingRecord_ShouldDoNothing() throws ExecutionException {
+    // Arrange
+
+    // Act Assert
+    assertThatCode(() -> storage.delete(prepareDeletes().get(0))).doesNotThrowAnyException();
+
+    Optional<Result> result = storage.get(prepareGet(0, 0));
+    assertThat(result).isNotPresent();
+  }
+
   @Test
   public void mutate_MultiplePutGiven_ShouldStoreProperly() throws ExecutionException, IOException {
     // Arrange