Fix race conditions in ManagerV2 tests

This commit fixes a number of race conditions in the ManagerV2 unit
tests. Most of them were due to the use of Testify's Eventually
function to read some values while some callbacks from the manager
would also modify those values. The simplest solution was to use the
atomic values on those cases.

One test (TestInputReload) had a race condition between the test and
the manager itself, so it was removed. There is an integration tests
that covers the same functionality.

CHANGELOG-developer.next.asciidoc

@@ -84,6 +84,7 @@ The list below covers the major changes between 7.0.0-rc2 and main only.
 - Skip HTTPJSON flakey test. {issue}34929[34929] {pull}35138[35138]
 - 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]
 
 ==== Added
 

x-pack/libbeat/management/managerV2_test.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -34,44 +35,44 @@ func TestManagerV2(t *testing.T) {
 	inputs := &reloadableList{}
 	r.MustRegisterInput(inputs)
 
-	configsSet := false
-	configsCleared := false
-	logLevelSet := false
-	fqdnEnabled := false
-	allStopped := false
+	configsSet := atomic.Bool{}
+	configsCleared := atomic.Bool{}
+	logLevelSet := atomic.Bool{}
+	fqdnEnabled := atomic.Bool{}
+	allStopped := atomic.Bool{}
 	onObserved := func(observed *proto.CheckinObserved, currentIdx int) {
 		if currentIdx == 1 {
 			oCfg := output.Config()
 			iCfgs := inputs.Configs()
 			if oCfg != nil && len(iCfgs) == 3 {
-				configsSet = true
+				configsSet.Store(true)
 				t.Logf("output and inputs configuration set")
 			}
 		} else if currentIdx == 2 {
 			oCfg := output.Config()
 			iCfgs := inputs.Configs()
 			if oCfg == nil || len(iCfgs) != 3 {
 				// should not happen (config no longer set)
-				configsSet = false
+				configsSet.Store(false)
 				t.Logf("output and inputs configuration cleared (should not happen)")
 			}
 		} else {
 			oCfg := output.Config()
 			iCfgs := inputs.Configs()
 			if oCfg == nil && len(iCfgs) == 0 {
-				configsCleared = true
+				configsCleared.Store(true)
 			}
 			if len(observed.Units) == 0 {
-				allStopped = true
+				allStopped.Store(true)
 				t.Logf("output and inputs configuration cleared (stopping)")
 			}
 		}
 		if logp.GetLevel() == zapcore.DebugLevel {
-			logLevelSet = true
+			logLevelSet.Store(true)
 			t.Logf("debug log level set")
 		}
 
-		fqdnEnabled = features.FQDN()
+		fqdnEnabled.Store(features.FQDN())
 		t.Logf("FQDN feature flag set to %v", fqdnEnabled)
 	}
 
@@ -218,7 +219,7 @@ func TestManagerV2(t *testing.T) {
 	defer m.Stop()
 
 	require.Eventually(t, func() bool {
-		return configsSet && configsCleared && logLevelSet && fqdnEnabled && allStopped
+		return configsSet.Load() && configsCleared.Load() && logLevelSet.Load() && fqdnEnabled.Load() && allStopped.Load()
 	}, 15*time.Second, 300*time.Millisecond)
 }
 
@@ -242,7 +243,7 @@ func TestOutputError(t *testing.T) {
 	}
 	r.MustRegisterInput(inputs)
 
-	stateReached := false
+	stateReached := atomic.Bool{}
 	units := []*proto.UnitExpected{
 		{
 			Id:             "output-unit",
@@ -300,7 +301,7 @@ func TestOutputError(t *testing.T) {
 	server := &mock.StubServerV2{
 		CheckinV2Impl: func(observed *proto.CheckinObserved) *proto.CheckinExpected {
 			if DoesStateMatch(observed, desiredState, 0) {
-				stateReached = true
+				stateReached.Store(true)
 			}
 			return &proto.CheckinExpected{
 				Units: units,
@@ -345,7 +346,7 @@ func TestOutputError(t *testing.T) {
 	defer m.Stop()
 
 	require.Eventually(t, func() bool {
-		return stateReached
+		return stateReached.Load()
 	}, 10*time.Second, 100*time.Millisecond, "desired state, output failed, was not reached")
 }