TestRangeSearch fails occasionally

[PumpkinSeed]

--- FAIL: TestRangeSearch (3.04s)
    fts_test.go:446: 
        	Error Trace:	fts_test.go:446
        	Error:      	Expected nil, but got: &errors.errorString{s:"[{\"error\":\"rest_auth: preparePerms, err: index not found\",\"request\":{\"ctl\":{\"timeout\":75000},\"query\":{\"end\":\"2019-09-16T22:13:03+02:00\",\"field\":\"something\",\"start\":\"2019-07-16T10:13:03+02:00\"}},\"status\":\"fail\"}\n]"}
        	Test:       	TestRangeSearch
210.815371ms
--- FAIL: TestRangeSearchWithFacet (3.23s)
    fts_test.go:513: 
        	Error Trace:	fts_test.go:513
        	Error:      	Expected nil, but got: &errors.errorString{s:"[{\"error\":\"rest_auth: preparePerms, err: index not found\",\"request\":{\"ctl\":{\"timeout\":75000},\"facets\":{\"BillingAddressAddress1\":{\"field\":\"BillingAddressAddress1\",\"size\":10}},\"query\":{\"end\":\"2019-09-16T22:13:06+02:00\",\"field\":\"something\",\"start\":\"2019-07-16T10:13:06+02:00\"}},\"status\":\"fail\"}\n]"}
        	Test:       	TestRangeSearchWithFacet
2019/10/07 18:13:37 Error when create secondary index An invalid index name was specified.
2019/10/07 18:13:37 Error when dropping index[] An invalid index name was specified.
{Service:1 Endpoint:127.0.0.1:11210 Success:true Latency:560.066µs}
{Service:4 Endpoint:http://127.0.0.1:8093 Success:true Latency:2.069186ms}
{Service:5 Endpoint:http://127.0.0.1:8094 Success:true Latency:25.111139ms}
{Service:6 Endpoint: Success:false Latency:0s}
{Service:1 Endpoint:127.0.0.1:11210 Success:true Latency:416.271µs}
{Service:4 Endpoint:http://127.0.0.1:8093 Success:true Latency:726.847µs}
{Service:5 Endpoint:http://127.0.0.1:8094 Success:true Latency:1.209528ms}

[PumpkinSeed]

Related to #71