This issue tracks testing that invoking all actions / undo actions within a saga "twice" is safe, and results in the same output as being called once.

• Instance create: [nexus] Make instance creation actions/undo actions idempotent #2095
• Instance delete: [nexus] Make instance deletion actions idempotent #2096
• Disk create: [nexus] Make disk creation saga idempotent #2097
• Disk Delete: [nexus] Make disk deletion saga idempotent #2098
• Snapshot Create
• Snapshot Delete
• Volume Delete
• Volume Remove ROP
• Project Creation
• Project Deletion
• VPC Creation
• VPC Deletion
• Instance Migration

Related to #2052, #1799