Testcase added for Moving files in snapshot layers

Movement of files/folder from base layer to folder in
new layer should be allowed

Signed-off-by: Kunal Kushwaha <kushwaha_kunal_v7@lab.ntt.co.jp>

snapshot/testsuite/testsuite.go

@@ -37,6 +37,7 @@ func SnapshotterSuite(t *testing.T, name string, snapshotterFn func(ctx context.
 	t.Run("DirectoryPermissionOnCommit", makeTest(name, snapshotterFn, checkDirectoryPermissionOnCommit))
 	t.Run("RemoveIntermediateSnapshot", makeTest(name, snapshotterFn, checkRemoveIntermediateSnapshot))
 	t.Run("DeletedFilesInChildSnapshot", makeTest(name, snapshotterFn, checkDeletedFilesInChildSnapshot))
+	t.Run("MoveFileFromLowerLayer", makeTest(name, snapshotterFn, checkFileFromLowerLayer))
 	// Rename test still fails on some kernels with overlay
 	//t.Run("Rename", makeTest(name, snapshotterFn, checkRename))
 
@@ -761,3 +762,25 @@ func checkSnapshotterViewReadonly(ctx context.Context, t *testing.T, snapshotter
 	assert.NoError(t, snapshotter.Remove(ctx, view))
 	assert.NoError(t, snapshotter.Remove(ctx, committed))
 }
+
+// Move files from base layer to new location in intermediate layer.
+// Verify if the file at source is deleted and copied to new location.
+func checkFileFromLowerLayer(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
+	l1Init := fstest.Apply(
+		fstest.CreateDir("/dir1", 0700),
+		fstest.CreateFile("/dir1/f1", []byte("Hello"), 0644),
+		fstest.CreateDir("dir2", 0700),
+		fstest.CreateFile("dir2/f2", []byte("..."), 0644),
+	)
+	l2Init := fstest.Apply(
+		fstest.CreateDir("/dir3", 0700),
+		fstest.CreateFile("/dir3/f1", []byte("Hello"), 0644),
+		fstest.RemoveAll("/dir1"),
+		fstest.Link("dir2/f2", "dir3/f2"),
+		fstest.RemoveAll("dir2/f2"),
+	)
+
+	if err := checkSnapshots(ctx, snapshotter, work, l1Init, l2Init); err != nil {
+		t.Fatalf("Check snapshots failed: %+v", err)
+	}
+}