func (s *metadataHelperSuite) TestWriteMetadataLegacyIndex(c *gc.C) {
	stor, _ := s.writeMetadataMultipleStream(c)
	// Read back the legacy index
	rdr, err := stor.Get("tools/streams/v1/index.json")
	defer rdr.Close()
	c.Assert(err, jc.ErrorIsNil)
	data, err := ioutil.ReadAll(rdr)
	c.Assert(err, jc.ErrorIsNil)
	var indices simplestreams.Indices
	err = json.Unmarshal(data, &indices)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(indices.Indexes, gc.HasLen, 1)
	indices.Updated = ""
	c.Assert(indices.Indexes["com.ubuntu.juju:released:tools"], gc.NotNil)
	indices.Indexes["com.ubuntu.juju:released:tools"].Updated = ""
	expected := simplestreams.Indices{
		Format: "index:1.0",
		Indexes: map[string]*simplestreams.IndexMetadata{
			"com.ubuntu.juju:released:tools": {
				Format:           "products:1.0",
				DataType:         "content-download",
				ProductsFilePath: "streams/v1/com.ubuntu.juju-released-tools.json",
				ProductIds:       []string{"com.ubuntu.juju:12.04:amd64"},
			},
		},
	}
	c.Assert(indices, jc.DeepEquals, expected)
}

// MarshalToolsMetadataIndexJSON marshals tools metadata to index JSON.
//
// updated is the time at which the JSON file was updated.
func MarshalToolsMetadataIndexJSON(metadata []*ToolsMetadata, updated time.Time) (out []byte, err error) {
	productIds := make([]string, len(metadata))
	for i, t := range metadata {
		productIds[i], err = t.productId()
		if err != nil {
			return nil, err
		}
	}
	var indices simplestreams.Indices
	indices.Updated = updated.Format(time.RFC1123Z)
	indices.Format = "index:1.0"
	indices.Indexes = map[string]*simplestreams.IndexMetadata{
		ToolsContentId: &simplestreams.IndexMetadata{
			Updated:          indices.Updated,
			Format:           "products:1.0",
			DataType:         "content-download",
			ProductsFilePath: ProductMetadataPath,
			ProductIds:       set.NewStrings(productIds...).SortedValues(),
		},
	}
	return json.MarshalIndent(&indices, "", "    ")
}

// MarshalImageMetadataIndexJSON marshals image metadata to index JSON.
//
// updated is the time at which the JSON file was updated.
func MarshalImageMetadataIndexJSON(metadata []*ImageMetadata, cloudSpec []simplestreams.CloudSpec,
	updated time.Time) (out []byte, err error) {

	productIds := make([]string, len(metadata))
	for i, t := range metadata {
		productIds[i] = t.productId()
	}
	var indices simplestreams.Indices
	indices.Updated = updated.Format(time.RFC1123Z)
	indices.Format = simplestreams.IndexFormat
	indices.Indexes = map[string]*simplestreams.IndexMetadata{
		ImageContentId: {
			CloudName:        "custom",
			Updated:          indices.Updated,
			Format:           simplestreams.ProductFormat,
			DataType:         "image-ids",
			ProductsFilePath: ProductMetadataPath,
			ProductIds:       set.NewStrings(productIds...).SortedValues(),
			Clouds:           cloudSpec,
		},
	}
	return json.MarshalIndent(&indices, "", "    ")
}

// marshalToolsMetadataIndexJSON marshals tools metadata to index JSON.
// updated is the time at which the JSON file was updated.
func marshalToolsMetadataIndexJSON(streamMetadata map[string][]*ToolsMetadata, updated time.Time) (out, outlegacy []byte, err error) {
	var indices simplestreams.Indices
	indices.Updated = updated.Format(time.RFC1123Z)
	indices.Format = simplestreams.IndexFormat
	indices.Indexes = make(map[string]*simplestreams.IndexMetadata, len(streamMetadata))

	var indicesLegacy simplestreams.Indices
	indicesLegacy.Updated = updated.Format(time.RFC1123Z)
	indicesLegacy.Format = simplestreams.IndexFormat

	for stream, metadata := range streamMetadata {
		var productIds []string
		for _, t := range metadata {
			id, err := t.productId()
			if err != nil {
				if series.IsUnknownSeriesVersionError(err) {
					logger.Infof("ignoring tools metadata with unknown series %q", t.Release)
					continue
				}
				return nil, nil, err
			}
			productIds = append(productIds, id)
		}
		indexMetadata := &simplestreams.IndexMetadata{
			Updated:          indices.Updated,
			Format:           simplestreams.ProductFormat,
			DataType:         ContentDownload,
			ProductsFilePath: ProductMetadataPath(stream),
			ProductIds:       set.NewStrings(productIds...).SortedValues(),
		}
		indices.Indexes[ToolsContentId(stream)] = indexMetadata
		if stream == ReleasedStream {
			indicesLegacy.Indexes = make(map[string]*simplestreams.IndexMetadata, 1)
			indicesLegacy.Indexes[ToolsContentId(stream)] = indexMetadata
		}
	}
	out, err = json.MarshalIndent(&indices, "", "    ")
	if len(indicesLegacy.Indexes) == 0 {
		return out, nil, err
	}
	outlegacy, err = json.MarshalIndent(&indicesLegacy, "", "    ")
	if err != nil {
		return nil, nil, err
	}
	return out, outlegacy, nil
}