grafana/public/app/features/expressions/ExpressionDatasource.test.ts

import { DataSourceInstanceSettings } from '@grafana/data';
import { backendSrv } from 'app/core/services/backend_srv';
import { ExpressionDatasourceApi } from './ExpressionDatasource';
import { ExpressionQueryType } from './types';

jest.mock('@grafana/runtime', () => ({
  ...(jest.requireActual('@grafana/runtime') as unknown as object),
  getBackendSrv: () => backendSrv,
  getTemplateSrv: () => ({
    replace: (val: string) => (val ? val.replace('$input', '10').replace('$window', '10s') : val),
  }),
}));

describe('ExpressionDatasourceApi', () => {
  beforeEach(() => {
    jest.clearAllMocks();
  });

  describe('expression queries with template variables', () => {
    it('should interpolate template variables in expression query', () => {
      const ds = new ExpressionDatasourceApi({} as DataSourceInstanceSettings);
      const query = ds.applyTemplateVariables(
        { type: ExpressionQueryType.math, refId: 'B', expression: '$input + 5 + $A' },
        {}
      );
      expect(query.expression).toBe('10 + 5 + $A');
    });
    it('should interpolate template variables in expression query', () => {
      const ds = new ExpressionDatasourceApi({} as DataSourceInstanceSettings);
      const query = ds.applyTemplateVariables(
        { type: ExpressionQueryType.resample, refId: 'B', window: '$window' },
        {}
      );
      expect(query.window).toBe('10s');
    });
  });
});