Add unit test for InfluxDB datasource

public/app/plugins/datasource/influxdb/specs/datasource.jest.ts

@@ -0,0 +1,53 @@
+import InfluxDatasource from '../datasource';
+import $q from 'q';
+import { TemplateSrvStub } from 'test/specs/helpers';
+
+describe('InfluxDataSource', () => {
+  let ctx: any = {
+    backendSrv: {},
+    $q: $q,
+    templateSrv: new TemplateSrvStub(),
+    instanceSettings: { url: 'url', name: 'influxDb', jsonData: {} },
+  };
+
+  beforeEach(function() {
+    ctx.instanceSettings.url = '/api/datasources/proxy/1';
+    ctx.ds = new InfluxDatasource(ctx.instanceSettings, ctx.$q, ctx.backendSrv, ctx.templateSrv);
+  });
+
+  describe('When issuing metricFindQuery', () => {
+    let query = 'SELECT max(value) FROM measurement WHERE $timeFilter';
+    let queryOptions: any = {
+      range: {
+        from: '2018-01-01 00:00:00',
+        to: '2018-01-02 00:00:00',
+      },
+    };
+    let requestQuery;
+
+    beforeEach(async () => {
+      ctx.backendSrv.datasourceRequest = function(req) {
+        requestQuery = req.params.q;
+        return ctx.$q.when({
+          results: [
+            {
+              series: [
+                {
+                  name: 'measurement',
+                  columns: ['max'],
+                  values: [[1]],
+                },
+              ],
+            },
+          ],
+        });
+      };
+
+      await ctx.ds.metricFindQuery(query, queryOptions).then(function(_) {});
+    });
+
+    it('should replace $timefilter', () => {
+      expect(requestQuery).toMatch('time >= 1514761200000ms and time <= 1514847600000ms');
+    });
+  });
+});