[Alerting]: Add alerting endpoint for Query Evaluation (#33174)

* [Alerting]: Add alerting endpoint for Query Evaluation

* Fix passing down now parameter

* Add validations and test

* Fix eval queries and expressions test

* Add eval tests

pkg/services/ngalert/api/tooling/definitions/testing.go

@@ -3,6 +3,9 @@ package definitions
 import (
 	"encoding/json"
 	"fmt"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
 
 	"github.com/grafana/grafana/pkg/services/ngalert/models"
 	"github.com/prometheus/alertmanager/config"
@@ -37,6 +40,19 @@ import (
 //     Responses:
 //       200: TestRuleResponse
 
+// swagger:route Post /api/v1/eval testing RouteEvalQueries
+//
+// Test rule
+//
+//     Consumes:
+//     - application/json
+//
+//     Produces:
+//     - application/json
+//
+//     Responses:
+//       200: EvalQueriesResponse
+
 // swagger:parameters RouteTestReceiverConfig
 type TestReceiverRequest struct {
 	// in:body
@@ -57,6 +73,18 @@ type TestRulePayload struct {
 	GrafanaManagedCondition *models.EvalAlertConditionCommand `json:"grafana_condition,omitempty"`
 }
 
+// swagger:parameters RouteEvalQueries
+type EvalQueriesRequest struct {
+	// in:body
+	Body EvalQueriesPayload
+}
+
+// swagger:model
+type EvalQueriesPayload struct {
+	Data []models.AlertQuery `json:"data"`
+	Now  time.Time           `json:"now"`
+}
+
 func (p *TestRulePayload) UnmarshalJSON(b []byte) error {
 	type plain TestRulePayload
 	if err := json.Unmarshal(b, (*plain)(p)); err != nil {
@@ -96,6 +124,9 @@ type TestRuleResponse struct {
 	GrafanaAlertInstances AlertInstancesResponse `json:"grafana_alert_instances"`
 }
 
+// swagger:model
+type EvalQueriesResponse = backend.QueryDataResponse
+
 // swagger:model
 type AlertInstancesResponse struct {
 	// Instances is an array of arrow encoded dataframes