Added unit tests

public/app/plugins/datasource/opentsdb/specs/datasource-specs.ts

@@ -51,6 +51,20 @@ describe('opentsdb', function() {
       expect(requestOptions.params.m).to.be('cpu{hostname=*}');
     });
 
+    it('tag_values(cpu, test) should generate lookup query', function() {
+      ctx.ds.metricFindQuery('tag_values(cpu, hostname, env=$env)').then(function(data) { results = data; });
+      ctx.$rootScope.$apply();
+      expect(requestOptions.url).to.be('/api/search/lookup');
+      expect(requestOptions.params.m).to.be('cpu{hostname=*, env=$env}');
+    });
+
+    it('tag_values(cpu, test) should generate lookup query', function() {
+      ctx.ds.metricFindQuery('tag_values(cpu, hostname, env=$env, region=$region)').then(function(data) { results = data; });
+      ctx.$rootScope.$apply();
+      expect(requestOptions.url).to.be('/api/search/lookup');
+      expect(requestOptions.params.m).to.be('cpu{hostname=*, env=$env, region=$region}');
+    });
+
     it('suggest_tagk() should generate api suggest query', function() {
       ctx.ds.metricFindQuery('suggest_tagk(foo)').then(function(data) { results = data; });
       ctx.$rootScope.$apply();