x-pack/filebeat/input/httpjson: re-enable previously flakey first_eve…

…nt test

With the change from concurrent to sequential processing this test is
no longer flakey. This is confirmed by re-applying a delay to the
publication of the first event in a set of events. This change causes
the concurrent code to fail consistently, but the current sequential
code passes.

The test change used to test the flake is

diff --git a/x-pack/filebeat/input/httpjson/request.go b/x-pack/filebeat/input/httpjson/request.go
index 6a1d926ab4..3ed904f16d 100644
--- a/x-pack/filebeat/input/httpjson/request.go
+++ b/x-pack/filebeat/input/httpjson/request.go
@@ -16,6 +16,7 @@ import (
        "reflect"
        "strconv"
        "strings"
+       "time"

        "github.com/PaesslerAG/jsonpath"

@@ -741,6 +742,10 @@ func newPublisher(trCtx *transformContext, pub inputcursor.Publisher, publish bo
 }

 func (p *publisher) event(_ context.Context, msg mapstr.M) {
+       if p.n == 0 {
+               time.Sleep(10 * time.Millisecond)
+       }
+
        if p.pub != nil {
                event, err := makeEvent(msg)
                if err != nil {

CHANGELOG-developer.next.asciidoc

@@ -86,6 +86,7 @@ The list below covers the major changes between 7.0.0-rc2 and main only.
 - Fix ingest pipeline for panw module to parse url scheme correctly {pull}35757[35757]
 - Renamed an httpjson input metric to follow naming conventions. `httpjson_interval_pages_total` was renamed to `httpjson_interval_pages` because the `_total` suffix is reserved for counters. {issue}35933[35933] {pull}36169[36169]
 - Fixed some race conditions in tests {pull}36185[36185]
+- Re-enable HTTPJSON fixed flakey test. {issue}34929[34929] {pull}[]
 
 ==== Added
 

x-pack/filebeat/input/httpjson/input_test.go

@@ -374,8 +374,6 @@ var testCases = []struct {
 		},
 	},
 	{
-		skipReason: "flakey test - see https://github.com/elastic/beats/issues/34929",
-
 		name: "first_event",
 		setupServer: func(t testing.TB, h http.HandlerFunc, config map[string]interface{}) {
 			server := httptest.NewServer(h)