[es] Add mock http server for the tests (#7607)

## Which problem is this PR solving?
- Resolves #7167 

## Description of the changes
- Mocked the http calls using `httptest` package to return immediate
response instead of waiting for requests to timeout.

## How was this change tested?
- GOMAXPROCS=6 go test -count=1 -parallel 128 -p 16
./internal/storage/v1/elasticsearch/

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [ ] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `npm run lint` and `npm run test`

---------

Signed-off-by: Tushar Anand <[email protected]>

Author: neoandmatrix

internal/storage/v1/elasticsearch/factory_test.go

@@ -317,8 +317,15 @@ func TestESStorageFactoryWithConfig(t *testing.T) {
 
 func TestESStorageFactoryWithConfigError(t *testing.T) {
 	t.Parallel()
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/" {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+	}))
+	defer server.Close()
 	cfg := escfg.Configuration{
-		Servers:            []string{"http://invalid-host-name:65535"},
+		Servers:            []string{server.URL},
 		DisableHealthCheck: true,
 		LogLevel:           "error",
 	}

internal/storage/v1/elasticsearch/factoryv1_test.go

@@ -103,6 +103,12 @@ func TestArchiveFactory(t *testing.T) {
 
 func TestFactoryInitializeErr(t *testing.T) {
 	t.Parallel()
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/" {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
+	}))
+	defer server.Close()
 	tests := []struct {
 		name        string
 		factory     *Factory
@@ -116,7 +122,7 @@ func TestFactoryInitializeErr(t *testing.T) {
 		{
 			name: "server error",
 			factory: &Factory{Options: &Options{Config: namespaceConfig{Configuration: escfg.Configuration{
-				Servers:            []string{"http://invalid-host-name:9200"},
+				Servers:            []string{server.URL},
 				DisableHealthCheck: true,
 			}}}},
 			expectedErr: "failed to create Elasticsearch client",