Report each anonymous volume's size and the space freed (issue 1796)

modules/docker/cmd/docker-tools/docker_test.go

@@ -441,6 +441,7 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 {"Name":"old","Driver":"local","CreatedAt":"2026-09-01T00:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
 {"Name":"young","Driver":"local","CreatedAt":"2026-10-04T11:00:00Z","Labels":{"com.docker.volume.anonymous":""}},
 {"Name":"named","Driver":"local","CreatedAt":"2026-01-01T00:00:00Z"}]`}).
+		on("docker system df --verbose", Ran{Stdout: `{"Volumes":[{"Name":"old","Size":"1.5MB"},{"Name":"young","Size":"1kB"}]}`}).
 		on("docker volume rm old", Ran{Stdout: "old\n"})
 	c := client(f, 1000)
 	before := time.Date(2026, 10, 3, 0, 0, 0, 0, time.UTC)
@@ -451,12 +452,15 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 	if f.ran("docker volume rm") || !reflect.DeepEqual(got["would_remove"], []string{"old"}) {
 		t.Fatalf("dry run: %v %+v", got, f.calls)
 	}
+	if got["would_free_bytes"] != int64(1500000) || got["sizes"].(map[string]string)["old"] != "1.5MB" {
+		t.Fatalf("dry run size: %v", got)
+	}
 	skipped := got["skipped"].([]map[string]any)
 	why := map[string]string{}
 	for _, s := range skipped {
 		why[s["name"].(string)] = s["why"].(string)
 	}
-	if len(why) != 3 || why["webdata"] == "" || why["young"] == "" || why["named"] == "" {
+	if len(why) != 3 || !strings.Contains(why["webdata"], "mesh holds") || why["young"] == "" || why["named"] == "" {
 		t.Fatalf("skipped: %v", skipped)
 	}
 	got, err = c.RemoveAnonymousVolumes(context.Background(), RemoveVolumesAsk{Why: "leftovers", CreatedBefore: &before})
@@ -466,6 +470,9 @@ func TestRemoveAnonymousVolumesTakesOnlyTheUnmountedAnonymousOnes(t *testing.T)
 	if !f.ran("docker volume rm old") || got["count"] != 1 || !reflect.DeepEqual(got["removed"], []string{"old"}) {
 		t.Fatalf("removed: %v %+v", got, f.calls)
 	}
+	if got["freed_bytes"] != int64(1500000) {
+		t.Fatalf("freed: %v", got)
+	}
 	for _, c := range f.calls {
 		if len(c.args) > 1 && c.args[0] == "volume" && c.args[1] == "rm" && (len(c.args) != 3 || c.args[2] != "old") {
 			t.Errorf("reached too far: %v", c.args)