feat(test): add ability to serve index.json using test repo server

Signed-off-by: Karuppiah Natarajan <karuppiah7890@gmail.com>

pkg/repo/repotest/server.go

@@ -24,8 +24,6 @@ import (
 
 	"helm.sh/helm/v3/internal/tlsutil"
 
-	"sigs.k8s.io/yaml"
-
 	"helm.sh/helm/v3/pkg/repo"
 )
 
@@ -79,9 +77,10 @@ func NewServer(docroot string) *Server {
 
 // Server is an implementation of a repository server for testing.
 type Server struct {
-	docroot    string
+	docroot          string
-	srv        *httptest.Server
+	srv              *httptest.Server
-	middleware http.HandlerFunc
+	middleware       http.HandlerFunc
+	jsonIndexEnabled bool
 }
 
 // WithMiddleware injects middleware in front of the server. This can be used to inject
@@ -95,6 +94,13 @@ func (s *Server) Root() string {
 	return s.docroot
 }
 
+// ServeJSONIndex allows you to enable or disable serving
+// index.json repository index file
+func (s *Server) ServeJSONIndex(enabled bool) {
+	s.jsonIndexEnabled = enabled
+	s.CreateIndex()
+}
+
 // CopyCharts takes a glob expression and copies those charts to the server root.
 func (s *Server) CopyCharts(origin string) ([]string, error) {
 	files, err := filepath.Glob(origin)
@@ -121,19 +127,34 @@ func (s *Server) CopyCharts(origin string) ([]string, error) {
 
 // CreateIndex will read docroot and generate an index.yaml file.
 func (s *Server) CreateIndex() error {
+
 	// generate the index
 	index, err := repo.IndexDirectory(s.docroot, s.URL())
 	if err != nil {
 		return err
 	}
 
-	d, err := yaml.Marshal(index)
+	yamlIndexFile := filepath.Join(s.docroot, "index.yaml")
+
+	err = index.WriteFile(yamlIndexFile, 0644)
+	if err != nil {
+		return err
+	}
+
+	jsonIndexFile := filepath.Join(s.docroot, "index.json")
+	// cleanup existing files
+	err = os.RemoveAll(jsonIndexFile)
 	if err != nil {
 		return err
 	}
 
-	ifile := filepath.Join(s.docroot, "index.yaml")
+	if s.jsonIndexEnabled {
-	return ioutil.WriteFile(ifile, d, 0644)
+		err = index.WriteJSONFile(jsonIndexFile, 0644)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 func (s *Server) Start() {

pkg/repo/repotest/server_test.go

@@ -16,6 +16,7 @@ limitations under the License.
 package repotest
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"net/http"
 	"path/filepath"
@@ -65,6 +66,9 @@ func TestServer(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	if res.StatusCode != 200 {
+		t.Fatalf("Expected 200, got %d", res.StatusCode)
+	}
 
 	data, err := ioutil.ReadAll(res.Body)
 	res.Body.Close()
@@ -94,6 +98,65 @@ func TestServer(t *testing.T) {
 	if res.StatusCode != 404 {
 		t.Fatalf("Expected 404, got %d", res.StatusCode)
 	}
+
+	// By default index.json should not be served,
+	// unless a toggle is enabled.
+	// So the below should give 404
+	res, err = http.Get(srv.URL() + "/index.json")
+	res.Body.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.StatusCode != 404 {
+		t.Fatalf("Expected 404, got %d", res.StatusCode)
+	}
+
+	// Let's enable the toggle to serve index.json
+	srv.ServeJSONIndex(true)
+
+	// Now we should be able to fetch the index.json
+	// with appropriate content
+
+	res, err = http.Get(srv.URL() + "/index.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if res.StatusCode != 200 {
+		t.Fatalf("Expected 200, got %d", res.StatusCode)
+	}
+
+	indexJSONData, err := ioutil.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	jsonIndex := repo.NewIndexFile()
+	if err := json.Unmarshal(indexJSONData, jsonIndex); err != nil {
+		t.Fatal(err)
+	}
+
+	if l := len(jsonIndex.Entries); l != 1 {
+		t.Fatalf("Expected 1 entry, got %d", l)
+	}
+
+	if !jsonIndex.Has(expect, "0.1.0") {
+		t.Errorf("missing %q", expect)
+	}
+
+	// Let's disable the toggle to serve index.json
+	srv.ServeJSONIndex(false)
+
+	// Now the below should give 404
+	res, err = http.Get(srv.URL() + "/index.json")
+	res.Body.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.StatusCode != 404 {
+		t.Fatalf("Expected 404, got %d", res.StatusCode)
+	}
 }
 
 func TestNewTempServer(t *testing.T) {