qemublocktest: Add 'snapshots' tests for backup bitmap handling

The 'snapshots' case has multiple layers so we need to make sure that
the bitmaps are merged with the appropriate temporary bitmaps formatted
from the allocation bitmap for any backing chain layer above.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

tests/qemublocktest.c

@@ -1267,6 +1267,10 @@ mymain(void)
     TEST_BACKUP_BITMAP_CALCULATE("basic-intermediate", bitmapSourceChain, "d", "basic");
     TEST_BACKUP_BITMAP_CALCULATE("basic-deep", bitmapSourceChain, "a", "basic");
 
+    TEST_BACKUP_BITMAP_CALCULATE("snapshots-flat", bitmapSourceChain, "current", "snapshots");
+    TEST_BACKUP_BITMAP_CALCULATE("snapshots-intermediate", bitmapSourceChain, "d", "snapshots");
+    TEST_BACKUP_BITMAP_CALCULATE("snapshots-deep", bitmapSourceChain, "a", "snapshots");
+
 #define TEST_CHECKPOINT_DELETE(testname, delbmp, named) \
     do { \
         checkpointdeletedata.name = testname; \

tests/qemublocktestdata/backupmerge/snapshots-deep-out.json

+[
+  {
+    "type": "block-dirty-bitmap-add",
+    "data": {
+      "node": "target_node",
+      "name": "target-bitmap-name",
+      "persistent": false,
+      "disabled": true,
+      "granularity": 65536
+    }
+  },
+  {
+    "type": "block-dirty-bitmap-merge",
+    "data": {
+      "node": "target_node",
+      "target": "target-bitmap-name",
+      "bitmaps": [
+        {
+          "node": "libvirt-1-format",
+          "name": "a"
+        },
+        {
+          "node": "libvirt-2-format",
+          "name": "a"
+        },
+        {
+          "node": "libvirt-3-format",
+          "name": "a"
+        },
+        {
+          "node": "libvirt-4-format",
+          "name": "a"
+        },
+        {
+          "node": "libvirt-5-format",
+          "name": "a"
+        }
+      ]
+    }
+  }
+]

tests/qemublocktestdata/backupmerge/snapshots-flat-out.json

+[
+  {
+    "type": "block-dirty-bitmap-add",
+    "data": {
+      "node": "target_node",
+      "name": "target-bitmap-name",
+      "persistent": false,
+      "disabled": true,
+      "granularity": 65536
+    }
+  },
+  {
+    "type": "block-dirty-bitmap-merge",
+    "data": {
+      "node": "target_node",
+      "target": "target-bitmap-name",
+      "bitmaps": [
+        {
+          "node": "libvirt-1-format",
+          "name": "current"
+        }
+      ]
+    }
+  }
+]

tests/qemublocktestdata/backupmerge/snapshots-intermediate-out.json

+[
+  {
+    "type": "block-dirty-bitmap-add",
+    "data": {
+      "node": "target_node",
+      "name": "target-bitmap-name",
+      "persistent": false,
+      "disabled": true,
+      "granularity": 65536
+    }
+  },
+  {
+    "type": "block-dirty-bitmap-merge",
+    "data": {
+      "node": "target_node",
+      "target": "target-bitmap-name",
+      "bitmaps": [
+        {
+          "node": "libvirt-1-format",
+          "name": "d"
+        },
+        {
+          "node": "libvirt-2-format",
+          "name": "d"
+        }
+      ]
+    }
+  }
+]