bootfromvolume unit tests.

Create requests the creation of a server from the given block device mapping.

DestinationLocal DestinationType is for using an ephemeral disk as the destination.

DestinationVolume DestinationType is for using a volume as the destination.

SourceBlank SourceType is for a "blank" or empty source.

SourceImage SourceType is for using images as the source of a block device.

SourceSnapshot SourceType is for using a volume snapshot as the source of a block device.

SourceVolume SourceType is for using a volume as the source of block device.

BlockDevice is a structure with options for creating block devices in a server.

CreateOptsExt is a structure that extends the server `CreateOpts` structure by allowing for a block device mapping.

CreateResult temporarily contains the response from a Create call.