case malformedEncoding:
			req, err = malformChunkSizeSigV4(req, testCase.chunkSize-1)
		case signatureMismatch:
			req, err = malformDataSigV4(req, 'z')
		case unexpectedEOF:
			req, err = truncateChunkByHalfSigv4(req)
		case tooBigDecodedLength:
			// Set decoded length to a large value out of int64 range to simulate parse failure.
			req.Header.Set("x-amz-decoded-content-length", "9999999999999999999999")
		}