Try to stabilize TestIncludesExcludes (#22514)

- Setup files/environment before running the test
  - reduce chance of races, especially with very slow/overloaded CI workers
  - fix t.Fatal being called from spawned go-routine (big NO NO)
- collect all found paths into a dictionary and assert wanted vs. found
  paths after
  - now checks for expected files that have not been found (semantic change)
  - assert will now print a 'diff' with missing/unknown paths on error

auditbeat/module/file_integrity/metricset_test.go

@@ -253,15 +253,13 @@ func TestIncludedExcludedFiles(t *testing.T) {
 	config["recursive"] = true
 	ms := mbtest.NewPushMetricSetV2(t, config)
 
-	go func() {
-		for _, f := range []string{"FILE.TXT", ".ssh/known_hosts", ".ssh/known_hosts.swp"} {
-			file := filepath.Join(dir, f)
-			err := ioutil.WriteFile(file, []byte("hello world"), 0600)
-			if err != nil {
-				t.Fatal(err)
-			}
+	for _, f := range []string{"FILE.TXT", ".ssh/known_hosts", ".ssh/known_hosts.swp"} {
+		file := filepath.Join(dir, f)
+		err := ioutil.WriteFile(file, []byte("hello world"), 0600)
+		if err != nil {
+			t.Fatal(err)
 		}
-	}()
+	}
 
 	events := mbtest.RunPushMetricSetV2(10*time.Second, 3, ms)
 	for _, e := range events {
@@ -278,14 +276,16 @@ func TestIncludedExcludedFiles(t *testing.T) {
 	if !assert.Len(t, events, len(wanted)) {
 		return
 	}
+
+	got := map[string]bool{}
 	for _, e := range events {
 		event := e.MetricSetFields
 		path, err := event.GetValue("file.path")
-		if assert.NoError(t, err) {
-			_, ok := wanted[path.(string)]
-			assert.True(t, ok)
+		if assert.NoError(t, err, "Failed to read file.path field") {
+			got[path.(string)] = true
 		}
 	}
+	assert.Equal(t, wanted, got)
 }
 
 func getConfig(path ...string) map[string]interface{} {