Fixes#1328
If `CompleteMultipartUpload` is attempted with empty `Parts` list, the gateway used to return `InvalidRequest`. Now it's changed to `MalformedXML`.
Fixes#1345
The previous implementation incorrectly parsed the `x-amz-sdk-checksum-algorithm` header for the `CompleteMultipartUpload` operation, even though this header is not expected and should be ignored. It also mistakenly treated the `x-amz-checksum-algorithm` header as an invalid value for `x-amz-checksum-x`.
The updated implementation only parses the `x-amz-sdk-checksum-algorithm` header for `PutObject` and `UploadPart` operations. Additionally, `x-amz-checksum-algorithm` and `x-amz-checksum-type` headers are now correctly ignored when parsing the precalculated checksum headers (`x-amz-checksum-x`).
Fixes#1339
`x-amz-checksum-type` and `x-amz-checksum-algorithm` request headers should be case insensitive in `CreateMultipartUpload`.
The changes include parsing the header values to upper case before validating and passing to back-end. `x-amz-checksum-type` response header was added in`CreateMultipartUpload`, which was missing before.
Fixes#1398
The `x-amz-mp-object-size` request header can have two erroneous states: an invalid value or a negative integer. AWS returns different error descriptions for each case. This PR fixes the error description for the invalid header value case.
The invalid case can't be integration tested as SDK expects `int64` as the header value.
