ENH: use a error variable not a custom error type

pkg/archiverappliance/aaclient.go

@@ -23,13 +23,6 @@ type AAclient struct {
 	baseURL string
 }
 
-type EmptyResponseError struct {
-}
-
-func (e *EmptyResponseError) Error() string {
-	return "response is empty"
-}
-
 func NewAAClient(ctx context.Context, url string) (*AAclient, error) {
 	return &AAclient{
 		baseURL: url,
@@ -163,7 +156,7 @@ func archiverSingleQueryParser(jsonAsBytes []byte) (models.SingleData, error) {
 
 	if len(response) < 1 {
 		log.DefaultLogger.Warn("Response is empty")
-		return sD, &EmptyResponseError{}
+		return sD, errEmptyResponse
 	}
 
 	var d models.DataResponse

pkg/archiverappliance/error.go

@@ -0,0 +1,7 @@
+package archiverappliance
+
+import "errors"
+
+var (
+	errEmptyResponse = errors.New("response is empty")
+)

pkg/archiverappliance/query.go

@@ -94,8 +94,7 @@ responseCollector:
 		select {
 		case response := <-responsePipe:
 			if response.err != nil {
-				emptyError := &EmptyResponseError{}
-				if qm.IgnoreEmptyErr && errors.Is(response.err, emptyError) {
+				if qm.IgnoreEmptyErr && errors.Is(response.err, errEmptyResponse) {
 					continue
 				}
 

pkg/archiverappliance/query_test.go

@@ -32,7 +32,7 @@ func (f fakeClient) ExecuteSingleQuery(target string, qm models.ArchiverQueryMod
 		return models.SingleData{}, errors.New("test error")
 	}
 	if target == "emptyErr" {
-		return models.SingleData{}, &EmptyResponseError{}
+		return models.SingleData{}, errEmptyResponse
 	}
 
 	var v models.Values
@@ -534,8 +534,7 @@ func TestQueryWithEmptyResponse(t *testing.T) {
 		t.Run(testCase.name, func(t *testing.T) {
 			result := Query(testCase.ctx, f, testCase.req, testCase.config)
 			res := result.Responses["A"]
-			emptyError := &EmptyResponseError{}
-			if !errors.Is(res.Error, emptyError) {
+			if !errors.Is(res.Error, errEmptyResponse) {
 				t.Errorf("An unexpected error has occurred")
 			}
 			if len(res.Frames) != 1 {