refactor(test): Stop SnapshotType being a str enum

With support for "mincore diff snapshots", we'll have two snapshot types
that map to "diff" in the firecracker API, so the enum can no longer be
string based. Instead just have a property that translates to
Firecracker API types.

Signed-off-by: Patrick Roy <roypat@amazon.co.uk>

Author: roypat

tests/framework/microvm.py

@@ -22,7 +22,7 @@
 import uuid
 from collections import namedtuple
 from dataclasses import dataclass
-from enum import Enum
+from enum import Enum, auto
 from functools import lru_cache
 from pathlib import Path
 from typing import Optional
@@ -49,8 +49,8 @@
 class SnapshotType(Enum):
     """Supported snapshot types."""
 
-    FULL = "Full"
-    DIFF = "Diff"
+    FULL = auto()
+    DIFF = auto()
 
     def __repr__(self):
         cls_name = self.__class__.__name__
@@ -66,6 +66,15 @@ def needs_dirty_page_tracking(self) -> bool:
         """Does taking this snapshot type require dirty page tracking to be enabled?"""
         return self == SnapshotType.DIFF
 
+    @property
+    def api_type(self) -> str:
+        """Converts this `SnapshotType` to the string value expected by the Firecracker API"""
+        match self:
+            case SnapshotType.FULL:
+                return "Full"
+            case SnapshotType.DIFF:
+                return "Diff"
+
 
 def hardlink_or_copy(src, dst):
     """If src and dst are in the same device, hardlink. Otherwise, copy."""
@@ -984,7 +993,7 @@ def make_snapshot(
         self.api.snapshot_create.put(
             mem_file_path=str(mem_path),
             snapshot_path=str(vmstate_path),
-            snapshot_type=snapshot_type.value,
+            snapshot_type=snapshot_type.api_type,
         )
         root = Path(self.chroot())
         return Snapshot(