[8.15](backport #5420) [Flaky Test] TestComponentBuildHashInDiagnostics improve agent state check (#5435)

* [Flaky Test] TestComponentBuildHashInDiagnostics improve agent state check (#5420)

ensure the agent status has components, all components are healthy and the version info is up-to-date

(cherry picked from commit 116e73f)

* manually backport de3dec4

---------

Co-authored-by: Anderson Queiroz <anderson.queiroz@elastic.co>

Author: mergify[bot]

pkg/testing/fixture_install.go

@@ -402,7 +402,7 @@ func getProcesses(t *gotesting.T, regex string) []runningProcess {
 //   - an error if any.
 func (f *Fixture) installDeb(ctx context.Context, installOpts *InstallOpts, opts []process.CmdOption) ([]byte, error) {
 	f.t.Logf("[test %s] Inside fixture installDeb function", f.t.Name())
-	//Prepare so that the f.srcPackage string is populated
+	// Prepare so that the f.srcPackage string is populated
 	err := f.EnsurePrepared(ctx)
 	if err != nil {
 		return nil, fmt.Errorf("failed to prepare: %w", err)
@@ -483,7 +483,7 @@ func (f *Fixture) installDeb(ctx context.Context, installOpts *InstallOpts, opts
 //   - an error if any.
 func (f *Fixture) installRpm(ctx context.Context, installOpts *InstallOpts, opts []process.CmdOption) ([]byte, error) {
 	f.t.Logf("[test %s] Inside fixture installRpm function", f.t.Name())
-	//Prepare so that the f.srcPackage string is populated
+	// Prepare so that the f.srcPackage string is populated
 	err := f.EnsurePrepared(ctx)
 	if err != nil {
 		return nil, fmt.Errorf("failed to prepare: %w", err)
@@ -649,12 +649,12 @@ func (f *Fixture) collectDiagnostics() {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
 	defer cancel()
 
-	dir, err := findProjectRoot(f.caller)
+	diagPath, err := f.DiagDir()
 	if err != nil {
-		f.t.Logf("failed to collect diagnostics; failed to find project root: %s", err)
+		f.t.Logf("failed to collect diagnostics: %v", err)
 		return
 	}
-	diagPath := filepath.Join(dir, "build", "diagnostics")
+
 	err = os.MkdirAll(diagPath, 0755)
 	if err != nil {
 		f.t.Logf("failed to collect diagnostics; failed to create %s: %s", diagPath, err)
@@ -699,6 +699,18 @@ func (f *Fixture) collectDiagnostics() {
 	}
 }
 
+// DiagDir returned {projectRoot}/build/diagnostics path. Files on this path
+// are saved if any test fails. Use it to save files for further investigation.
+func (f *Fixture) DiagDir() (string, error) {
+	dir, err := findProjectRoot(f.caller)
+	if err != nil {
+		return "", fmt.Errorf("failed to find project root: %w", err)
+	}
+
+	diagPath := filepath.Join(dir, "build", "diagnostics")
+	return diagPath, nil
+}
+
 func (f *Fixture) archiveInstallDirectory(installPath string, outputPath string) error {
 	file, err := os.Create(outputPath)
 	if err != nil {

testing/integration/package_version_test.go

@@ -11,6 +11,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -91,27 +92,60 @@ func TestComponentBuildHashInDiagnostics(t *testing.T) {
 		"failed to install start agent [output: %s]", string(output))
 
 	stateBuff := bytes.Buffer{}
+	var status atesting.AgentStatusOutput
 	allHealthy := func() bool {
 		stateBuff.Reset()
 
-		status, err := f.ExecStatus(ctx)
+		status, err = f.ExecStatus(ctx)
 		if err != nil {
 			stateBuff.WriteString(fmt.Sprintf("failed to get agent status: %v",
 				err))
 			return false
 		}
 
+		if client.State(status.State) != client.Healthy {
+			stateBuff.WriteString(fmt.Sprintf(
+				"agent isn't healthy: %s-%s",
+				client.State(status.State), status.Message))
+			return false
+		}
+
+		if len(status.Components) == 0 {
+			stateBuff.WriteString(fmt.Sprintf(
+				"healthy but without components: agent status: %s-%s",
+				client.State(status.State), status.Message))
+			return false
+		}
+
+		// the agent might be healthy but waiting its first configuration,
+		// in that case, there would be no components yet. Therefore, ensure
+		// the agent received the policy with components before proceeding with
+		// the test.
 		for _, c := range status.Components {
+			bs, err := json.MarshalIndent(status, "", "  ")
+			if err != nil {
+				stateBuff.WriteString(fmt.Sprintf(
+					"%s not healthy, could not marshal status outptu: %v",
+					c.Name, err))
+				return false
+			}
+
 			state := client.State(c.State)
 			if state != client.Healthy {
-				bs, err := json.MarshalIndent(status, "", "  ")
-				if err != nil {
-					stateBuff.WriteString(fmt.Sprintf("%s not health, could not marshal status outptu: %v",
-						c.Name, err))
-					return false
-				}
-
-				stateBuff.WriteString(fmt.Sprintf("%s not health, agent status output: %s",
+				stateBuff.WriteString(fmt.Sprintf(
+					"%s not health, agent status output: %s",
+					c.Name, bs))
+				return false
+			}
+
+			// there is a rare a race condition unlike to happen on a
+			// production scenario where the component is healthy but the
+			// version info delays to update. As the Status command and the
+			// diagnostics fetch this information in the same way, it guarantees
+			// the version info is up-to-date before proceeding with the test.
+			if c.VersionInfo.Meta.Commit == "" {
+				stateBuff.WriteString(fmt.Sprintf(
+					"%s health, but no versionInfo. agent status output: %s",
 					c.Name, bs))
 				return false
 			}
@@ -123,6 +157,13 @@ func TestComponentBuildHashInDiagnostics(t *testing.T) {
 		allHealthy,
 		5*time.Minute, 10*time.Second,
 		"agent never became healthy. Last status: %v", &stateBuff)
+	defer func() {
+		if !t.Failed() {
+			return
+		}
+
+		t.Logf("test failed: last status output: %#v", status)
+	}()
 
 	agentbeat := "agentbeat"
 	if runtime.GOOS == "windows" {
@@ -159,6 +200,28 @@ func TestComponentBuildHashInDiagnostics(t *testing.T) {
 
 	diag := t.TempDir()
 	extractZipArchive(t, diagZip, diag)
+	// if the test fails, the diagnostics used is useful for debugging.
+	defer func() {
+		if !t.Failed() {
+			return
+		}
+
+		t.Logf("the test failed: trying to save the diagnostics used on the test")
+		diagDir, err := f.DiagDir()
+		if err != nil {
+			t.Logf("could not get diagnostics directory to save the diagnostics used on the test")
+			return
+		}
+
+		err = os.Rename(diagZip, filepath.Join(diagDir,
+			fmt.Sprintf("TestComponentBuildHashInDiagnostics-used-diag-%d.zip",
+				time.Now().Unix())))
+		if err != nil {
+			t.Logf("could not move diagnostics used in the test to %s: %v",
+				diagDir, err)
+			return
+		}
+	}()
 
 	stateFilePath := filepath.Join(diag, "state.yaml")
 	stateYAML, err := os.Open(stateFilePath)
@@ -192,6 +255,19 @@ func TestComponentBuildHashInDiagnostics(t *testing.T) {
 		assert.Equalf(t, wantBuildHash, c.State.VersionInfo.Meta.Commit,
 			"component %s: VersionInfo.Meta.Commit mismatch", c.ID)
 	}
+
+	if t.Failed() {
+		_, seek := stateYAML.Seek(0, 0)
+		if seek != nil {
+			t.Logf("could not reset state.yaml offset to print it")
+			return
+		}
+		data, err := io.ReadAll(stateYAML)
+		if err != nil {
+			t.Logf("could not read state.yaml: %v", err)
+		}
+		t.Logf("test failed: state.yaml contents: %q", string(data))
+	}
 }
 
 func testVersionWithRunningAgent(runCtx context.Context, f *atesting.Fixture) func(*testing.T) {