Adding additional test coverage to account for all isInitialVersion codepaths

Author: RanVaknin

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/extensions/VersionedRecordExtension.java

@@ -147,7 +147,6 @@ public WriteModification beforeWrite(DynamoDbExtensionContext.BeforeWrite contex
 
         Pair<AttributeValue, Expression> updates = getRecordUpdates(versionAttributeKey.get(), context);
 
-        // Unpack values from Pair
         AttributeValue newVersionValue = updates.left();
         Expression condition = updates.right();
 
@@ -168,7 +167,6 @@ private Pair<AttributeValue, Expression> getRecordUpdates(String versionAttribut
         AttributeValue existingVersionValue = itemToTransform.getOrDefault(versionAttributeKey, DEFAULT_VALUE);
 
         if (isInitialVersion(existingVersionValue, context)) {
-            // First version of the record ensure it does not exist
             return createInitialRecord(versionAttributeKey, context);
         }
         // Existing record, increment version
@@ -230,7 +228,6 @@ private Pair<AttributeValue, Expression> updateExistingRecord(String versionAttr
 
     private int getExistingVersion(AttributeValue existingVersionValue) {
         if (existingVersionValue.n() == null) {
-            // In this case a non-null version attribute is present, but it's not an N
             throw new IllegalArgumentException("Version attribute appears to be the wrong type. N is required.");
         }
 

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/extensions/VersionedRecordExtensionTest.java

@@ -294,11 +294,34 @@ public void beforeWrite_versionNotEqualsAnnotationStartAt_notTreatedAsInitialVer
                                             .tableMetadata(schema.tableMetadata())
                                             .operationContext(PRIMARY_CONTEXT).build());
 
-        // Should be treated as existing version
         assertThat(result.additionalConditionalExpression().expression(),
                    is("#AMZN_MAPPED_version = :old_version_value"));
     }
 
+    @Test
+    public void beforeWrite_versionEqualsAnnotationStartAt_isTreatedAsInitialVersion() {
+        FakeVersionedThroughAnnotationItem item = new FakeVersionedThroughAnnotationItem();
+        item.setId(UUID.randomUUID().toString());
+        item.setVersion(3);
+
+        TableSchema<FakeVersionedThroughAnnotationItem> schema =
+            TableSchema.fromBean(FakeVersionedThroughAnnotationItem.class);
+
+        Map<String, AttributeValue> inputMap = new HashMap<>(schema.itemToMap(item, true));
+
+        VersionedRecordExtension recordExtension = VersionedRecordExtension.builder().build();
+
+        WriteModification result =
+            recordExtension.beforeWrite(DefaultDynamoDbExtensionContext
+                                            .builder()
+                                            .items(inputMap)
+                                            .tableMetadata(schema.tableMetadata())
+                                            .operationContext(PRIMARY_CONTEXT).build());
+
+        assertThat(result.additionalConditionalExpression().expression(),
+                   is("attribute_not_exists(#AMZN_MAPPED_version)"));
+    }
+
 
     @DynamoDbBean
     public static class FakeVersionedThroughAnnotationItem {