// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package v1

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"math"
	"net/http"
	"net/http/httptest"
	"net/url"
	"reflect"
	"strings"
	"testing"
	"time"

	"github.com/gogo/protobuf/proto"
	"github.com/golang/snappy"
	"github.com/prometheus/common/model"
	"github.com/prometheus/common/route"

	"github.com/prometheus/prometheus/config"
	"github.com/prometheus/prometheus/pkg/labels"
	"github.com/prometheus/prometheus/pkg/timestamp"
	"github.com/prometheus/prometheus/prompb"
	"github.com/prometheus/prometheus/promql"
	"github.com/prometheus/prometheus/scrape"
	"github.com/prometheus/prometheus/storage"
	"github.com/prometheus/prometheus/storage/remote"
)

type testTargetRetriever struct{}

func (t testTargetRetriever) TargetsActive() []*scrape.Target {
	return []*scrape.Target{
		scrape.NewTarget(
			labels.FromMap(map[string]string{
				model.SchemeLabel:      "http",
				model.AddressLabel:     "example.com:8080",
				model.MetricsPathLabel: "/metrics",
			}),
			nil,
			url.Values{},
		),
	}
}
func (t testTargetRetriever) TargetsDropped() []*scrape.Target {
	return []*scrape.Target{
		scrape.NewTarget(
			nil,
			labels.FromMap(map[string]string{
				model.AddressLabel:     "http://dropped.example.com:9115",
				model.MetricsPathLabel: "/probe",
				model.SchemeLabel:      "http",
				model.JobLabel:         "blackbox",
			}),
			url.Values{},
		),
	}
}

type testAlertmanagerRetriever struct{}

func (t testAlertmanagerRetriever) Alertmanagers() []*url.URL {
	return []*url.URL{
		{
			Scheme: "http",
			Host:   "alertmanager.example.com:8080",
			Path:   "/api/v1/alerts",
		},
	}
}

func (t testAlertmanagerRetriever) DroppedAlertmanagers() []*url.URL {
	return []*url.URL{
		{
			Scheme: "http",
			Host:   "dropped.alertmanager.example.com:8080",
			Path:   "/api/v1/alerts",
		},
	}
}

var samplePrometheusCfg = config.Config{
	GlobalConfig:       config.GlobalConfig{},
	AlertingConfig:     config.AlertingConfig{},
	RuleFiles:          []string{},
	ScrapeConfigs:      []*config.ScrapeConfig{},
	RemoteWriteConfigs: []*config.RemoteWriteConfig{},
	RemoteReadConfigs:  []*config.RemoteReadConfig{},
}

var sampleFlagMap = map[string]string{
	"flag1": "value1",
	"flag2": "value2",
}

func TestEndpoints(t *testing.T) {
	suite, err := promql.NewTest(t, `
		load 1m
			test_metric1{foo="bar"} 0+100x100
			test_metric1{foo="boo"} 1+0x100
			test_metric2{foo="boo"} 1+0x100
	`)
	if err != nil {
		t.Fatal(err)
	}
	defer suite.Close()

	if err := suite.Run(); err != nil {
		t.Fatal(err)
	}

	now := time.Now()

	var tr testTargetRetriever

	var ar testAlertmanagerRetriever

	api := &API{
		Queryable:             suite.Storage(),
		QueryEngine:           suite.QueryEngine(),
		targetRetriever:       tr,
		alertmanagerRetriever: ar,
		now:      func() time.Time { return now },
		config:   func() config.Config { return samplePrometheusCfg },
		flagsMap: sampleFlagMap,
		ready:    func(f http.HandlerFunc) http.HandlerFunc { return f },
	}

	start := time.Unix(0, 0)

	var tests = []struct {
		endpoint apiFunc
		params   map[string]string
		query    url.Values
		response interface{}
		errType  errorType
	}{
		{
			endpoint: api.query,
			query: url.Values{
				"query": []string{"2"},
				"time":  []string{"123.4"},
			},
			response: &queryData{
				ResultType: promql.ValueTypeScalar,
				Result: promql.Scalar{
					V: 2,
					T: timestamp.FromTime(start.Add(123*time.Second + 400*time.Millisecond)),
				},
			},
		},
		{
			endpoint: api.query,
			query: url.Values{
				"query": []string{"0.333"},
				"time":  []string{"1970-01-01T00:02:03Z"},
			},
			response: &queryData{
				ResultType: promql.ValueTypeScalar,
				Result: promql.Scalar{
					V: 0.333,
					T: timestamp.FromTime(start.Add(123 * time.Second)),
				},
			},
		},
		{
			endpoint: api.query,
			query: url.Values{
				"query": []string{"0.333"},
				"time":  []string{"1970-01-01T01:02:03+01:00"},
			},
			response: &queryData{
				ResultType: promql.ValueTypeScalar,
				Result: promql.Scalar{
					V: 0.333,
					T: timestamp.FromTime(start.Add(123 * time.Second)),
				},
			},
		},
		{
			endpoint: api.query,
			query: url.Values{
				"query": []string{"0.333"},
			},
			response: &queryData{
				ResultType: promql.ValueTypeScalar,
				Result: promql.Scalar{
					V: 0.333,
					T: timestamp.FromTime(now),
				},
			},
		},
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"0"},
				"end":   []string{"2"},
				"step":  []string{"1"},
			},
			response: &queryData{
				ResultType: promql.ValueTypeMatrix,
				Result: promql.Matrix{
					promql.Series{
						Points: []promql.Point{
							{V: 0, T: timestamp.FromTime(start)},
							{V: 1, T: timestamp.FromTime(start.Add(1 * time.Second))},
							{V: 2, T: timestamp.FromTime(start.Add(2 * time.Second))},
						},
						Metric: nil,
					},
				},
			},
		},
		// Missing query params in range queries.
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"end":   []string{"2"},
				"step":  []string{"1"},
			},
			errType: errorBadData,
		},
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"0"},
				"step":  []string{"1"},
			},
			errType: errorBadData,
		},
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"0"},
				"end":   []string{"2"},
			},
			errType: errorBadData,
		},
		// Bad query expression.
		{
			endpoint: api.query,
			query: url.Values{
				"query": []string{"invalid][query"},
				"time":  []string{"1970-01-01T01:02:03+01:00"},
			},
			errType: errorBadData,
		},
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"invalid][query"},
				"start": []string{"0"},
				"end":   []string{"100"},
				"step":  []string{"1"},
			},
			errType: errorBadData,
		},
		// Invalid step.
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"1"},
				"end":   []string{"2"},
				"step":  []string{"0"},
			},
			errType: errorBadData,
		},
		// Start after end.
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"2"},
				"end":   []string{"1"},
				"step":  []string{"1"},
			},
			errType: errorBadData,
		},
		// Start overflows int64 internally.
		{
			endpoint: api.queryRange,
			query: url.Values{
				"query": []string{"time()"},
				"start": []string{"148966367200.372"},
				"end":   []string{"1489667272.372"},
				"step":  []string{"1"},
			},
			errType: errorBadData,
		},
		{
			endpoint: api.labelValues,
			params: map[string]string{
				"name": "__name__",
			},
			response: []string{
				"test_metric1",
				"test_metric2",
			},
		},
		{
			endpoint: api.labelValues,
			params: map[string]string{
				"name": "foo",
			},
			response: []string{
				"bar",
				"boo",
			},
		},
		// Bad name parameter.
		{
			endpoint: api.labelValues,
			params: map[string]string{
				"name": "not!!!allowed",
			},
			errType: errorBadData,
		},
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric2", "foo", "boo"),
			},
		},
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric1{foo=~".+o"}`},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric1", "foo", "boo"),
			},
		},
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric1{foo=~".+o$"}`, `test_metric1{foo=~".+o"}`},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric1", "foo", "boo"),
			},
		},
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric1{foo=~".+o"}`, `none`},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric1", "foo", "boo"),
			},
		},
		// Start and end before series starts.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"-2"},
				"end":     []string{"-1"},
			},
			response: []labels.Labels{},
		},
		// Start and end after series ends.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"100000"},
				"end":     []string{"100001"},
			},
			response: []labels.Labels{},
		},
		// Start before series starts, end after series ends.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"-1"},
				"end":     []string{"100000"},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric2", "foo", "boo"),
			},
		},
		// Start and end within series.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"1"},
				"end":     []string{"100"},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric2", "foo", "boo"),
			},
		},
		// Start within series, end after.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"1"},
				"end":     []string{"100000"},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric2", "foo", "boo"),
			},
		},
		// Start before series, end within series.
		{
			endpoint: api.series,
			query: url.Values{
				"match[]": []string{`test_metric2`},
				"start":   []string{"-1"},
				"end":     []string{"1"},
			},
			response: []labels.Labels{
				labels.FromStrings("__name__", "test_metric2", "foo", "boo"),
			},
		},
		// Missing match[] query params in series requests.
		{
			endpoint: api.series,
			errType:  errorBadData,
		},
		{
			endpoint: api.dropSeries,
			errType:  errorInternal,
		},
		{
			endpoint: api.targets,
			response: &TargetDiscovery{
				ActiveTargets: []*Target{
					{
						DiscoveredLabels: map[string]string{},
						Labels:           map[string]string{},
						ScrapeURL:        "http://example.com:8080/metrics",
						Health:           "unknown",
					},
				},
				DroppedTargets: []*DroppedTarget{
					{
						DiscoveredLabels: map[string]string{
							"__address__":      "http://dropped.example.com:9115",
							"__metrics_path__": "/probe",
							"__scheme__":       "http",
							"job":              "blackbox",
						},
					},
				},
			},
		},
		{
			endpoint: api.alertmanagers,
			response: &AlertmanagerDiscovery{
				ActiveAlertmanagers: []*AlertmanagerTarget{
					{
						URL: "http://alertmanager.example.com:8080/api/v1/alerts",
					},
				},
				DroppedAlertmanagers: []*AlertmanagerTarget{
					{
						URL: "http://dropped.alertmanager.example.com:8080/api/v1/alerts",
					},
				},
			},
		},
		{
			endpoint: api.serveConfig,
			response: &prometheusConfig{
				YAML: samplePrometheusCfg.String(),
			},
		},
		{
			endpoint: api.serveFlags,
			response: sampleFlagMap,
		},
	}

	methods := func(f apiFunc) []string {
		fp := reflect.ValueOf(f).Pointer()
		if fp == reflect.ValueOf(api.query).Pointer() || fp == reflect.ValueOf(api.queryRange).Pointer() {
			return []string{http.MethodGet, http.MethodPost}
		}
		return []string{http.MethodGet}
	}

	request := func(m string, q url.Values) (*http.Request, error) {
		if m == http.MethodPost {
			r, err := http.NewRequest(m, "http://example.com", strings.NewReader(q.Encode()))
			r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
			return r, err
		}
		return http.NewRequest(m, fmt.Sprintf("http://example.com?%s", q.Encode()), nil)
	}

	for _, test := range tests {
		for _, method := range methods(test.endpoint) {
			// Build a context with the correct request params.
			ctx := context.Background()
			for p, v := range test.params {
				ctx = route.WithParam(ctx, p, v)
			}
			t.Logf("run %s\t%q", method, test.query.Encode())

			req, err := request(method, test.query)
			if err != nil {
				t.Fatal(err)
			}
			resp, apiErr := test.endpoint(req.WithContext(ctx))
			if apiErr != nil {
				if test.errType == errorNone {
					t.Fatalf("Unexpected error: %s", apiErr)
				}
				if test.errType != apiErr.typ {
					t.Fatalf("Expected error of type %q but got type %q", test.errType, apiErr.typ)
				}
				continue
			}
			if apiErr == nil && test.errType != errorNone {
				t.Fatalf("Expected error of type %q but got none", test.errType)
			}
			if !reflect.DeepEqual(resp, test.response) {
				t.Fatalf("Response does not match, expected:\n%+v\ngot:\n%+v", test.response, resp)
			}
		}
	}
}

func TestReadEndpoint(t *testing.T) {
	suite, err := promql.NewTest(t, `
		load 1m
			test_metric1{foo="bar",baz="qux"} 1
	`)
	if err != nil {
		t.Fatal(err)
	}
	defer suite.Close()

	if err := suite.Run(); err != nil {
		t.Fatal(err)
	}

	api := &API{
		Queryable:   suite.Storage(),
		QueryEngine: suite.QueryEngine(),
		config: func() config.Config {
			return config.Config{
				GlobalConfig: config.GlobalConfig{
					ExternalLabels: model.LabelSet{
						"baz": "a",
						"b":   "c",
						"d":   "e",
					},
				},
			}
		},
	}

	// Encode the request.
	matcher1, err := labels.NewMatcher(labels.MatchEqual, "__name__", "test_metric1")
	if err != nil {
		t.Fatal(err)
	}
	matcher2, err := labels.NewMatcher(labels.MatchEqual, "d", "e")
	if err != nil {
		t.Fatal(err)
	}
	query, err := remote.ToQuery(0, 1, []*labels.Matcher{matcher1, matcher2}, &storage.SelectParams{Step: 0, Func: "avg"})
	if err != nil {
		t.Fatal(err)
	}
	req := &prompb.ReadRequest{Queries: []*prompb.Query{query}}
	data, err := proto.Marshal(req)
	if err != nil {
		t.Fatal(err)
	}
	compressed := snappy.Encode(nil, data)
	request, err := http.NewRequest("POST", "", bytes.NewBuffer(compressed))
	if err != nil {
		t.Fatal(err)
	}
	recorder := httptest.NewRecorder()
	api.remoteRead(recorder, request)

	// Decode the response.
	compressed, err = ioutil.ReadAll(recorder.Result().Body)
	if err != nil {
		t.Fatal(err)
	}
	uncompressed, err := snappy.Decode(nil, compressed)
	if err != nil {
		t.Fatal(err)
	}

	var resp prompb.ReadResponse
	err = proto.Unmarshal(uncompressed, &resp)
	if err != nil {
		t.Fatal(err)
	}

	if len(resp.Results) != 1 {
		t.Fatalf("Expected 1 result, got %d", len(resp.Results))
	}

	result := resp.Results[0]
	expected := &prompb.QueryResult{
		Timeseries: []*prompb.TimeSeries{
			{
				Labels: []*prompb.Label{
					{Name: "__name__", Value: "test_metric1"},
					{Name: "b", Value: "c"},
					{Name: "baz", Value: "qux"},
					{Name: "d", Value: "e"},
					{Name: "foo", Value: "bar"},
				},
				Samples: []*prompb.Sample{{Value: 1, Timestamp: 0}},
			},
		},
	}
	if !reflect.DeepEqual(result, expected) {
		t.Fatalf("Expected response \n%v\n but got \n%v\n", result, expected)
	}
}

func TestRespondSuccess(t *testing.T) {
	s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		respond(w, "test")
	}))
	defer s.Close()

	resp, err := http.Get(s.URL)
	if err != nil {
		t.Fatalf("Error on test request: %s", err)
	}
	body, err := ioutil.ReadAll(resp.Body)
	defer resp.Body.Close()
	if err != nil {
		t.Fatalf("Error reading response body: %s", err)
	}

	if resp.StatusCode != 200 {
		t.Fatalf("Return code %d expected in success response but got %d", 200, resp.StatusCode)
	}
	if h := resp.Header.Get("Content-Type"); h != "application/json" {
		t.Fatalf("Expected Content-Type %q but got %q", "application/json", h)
	}

	var res response
	if err = json.Unmarshal([]byte(body), &res); err != nil {
		t.Fatalf("Error unmarshaling JSON body: %s", err)
	}

	exp := &response{
		Status: statusSuccess,
		Data:   "test",
	}
	if !reflect.DeepEqual(&res, exp) {
		t.Fatalf("Expected response \n%v\n but got \n%v\n", res, exp)
	}
}

func TestRespondError(t *testing.T) {
	s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		respondError(w, &apiError{errorTimeout, errors.New("message")}, "test")
	}))
	defer s.Close()

	resp, err := http.Get(s.URL)
	if err != nil {
		t.Fatalf("Error on test request: %s", err)
	}
	body, err := ioutil.ReadAll(resp.Body)
	defer resp.Body.Close()
	if err != nil {
		t.Fatalf("Error reading response body: %s", err)
	}

	if want, have := http.StatusServiceUnavailable, resp.StatusCode; want != have {
		t.Fatalf("Return code %d expected in error response but got %d", want, have)
	}
	if h := resp.Header.Get("Content-Type"); h != "application/json" {
		t.Fatalf("Expected Content-Type %q but got %q", "application/json", h)
	}

	var res response
	if err = json.Unmarshal([]byte(body), &res); err != nil {
		t.Fatalf("Error unmarshaling JSON body: %s", err)
	}

	exp := &response{
		Status:    statusError,
		Data:      "test",
		ErrorType: errorTimeout,
		Error:     "message",
	}
	if !reflect.DeepEqual(&res, exp) {
		t.Fatalf("Expected response \n%v\n but got \n%v\n", res, exp)
	}
}

func TestParseTime(t *testing.T) {
	ts, err := time.Parse(time.RFC3339Nano, "2015-06-03T13:21:58.555Z")
	if err != nil {
		panic(err)
	}

	var tests = []struct {
		input  string
		fail   bool
		result time.Time
	}{
		{
			input: "",
			fail:  true,
		}, {
			input: "abc",
			fail:  true,
		}, {
			input: "30s",
			fail:  true,
		}, {
			input:  "123",
			result: time.Unix(123, 0),
		}, {
			input:  "123.123",
			result: time.Unix(123, 123000000),
		}, {
			input:  "2015-06-03T13:21:58.555Z",
			result: ts,
		}, {
			input:  "2015-06-03T14:21:58.555+01:00",
			result: ts,
		},
	}

	for _, test := range tests {
		ts, err := parseTime(test.input)
		if err != nil && !test.fail {
			t.Errorf("Unexpected error for %q: %s", test.input, err)
			continue
		}
		if err == nil && test.fail {
			t.Errorf("Expected error for %q but got none", test.input)
			continue
		}
		if !test.fail && !ts.Equal(test.result) {
			t.Errorf("Expected time %v for input %q but got %v", test.result, test.input, ts)
		}
	}
}

func TestParseDuration(t *testing.T) {
	var tests = []struct {
		input  string
		fail   bool
		result time.Duration
	}{
		{
			input: "",
			fail:  true,
		}, {
			input: "abc",
			fail:  true,
		}, {
			input: "2015-06-03T13:21:58.555Z",
			fail:  true,
		}, {
			// Internal int64 overflow.
			input: "-148966367200.372",
			fail:  true,
		}, {
			// Internal int64 overflow.
			input: "148966367200.372",
			fail:  true,
		}, {
			input:  "123",
			result: 123 * time.Second,
		}, {
			input:  "123.333",
			result: 123*time.Second + 333*time.Millisecond,
		}, {
			input:  "15s",
			result: 15 * time.Second,
		}, {
			input:  "5m",
			result: 5 * time.Minute,
		},
	}

	for _, test := range tests {
		d, err := parseDuration(test.input)
		if err != nil && !test.fail {
			t.Errorf("Unexpected error for %q: %s", test.input, err)
			continue
		}
		if err == nil && test.fail {
			t.Errorf("Expected error for %q but got none", test.input)
			continue
		}
		if !test.fail && d != test.result {
			t.Errorf("Expected duration %v for input %q but got %v", test.result, test.input, d)
		}
	}
}

func TestOptionsMethod(t *testing.T) {
	r := route.New()
	api := &API{ready: func(f http.HandlerFunc) http.HandlerFunc { return f }}
	api.Register(r)

	s := httptest.NewServer(r)
	defer s.Close()

	req, err := http.NewRequest("OPTIONS", s.URL+"/any_path", nil)
	if err != nil {
		t.Fatalf("Error creating OPTIONS request: %s", err)
	}
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		t.Fatalf("Error executing OPTIONS request: %s", err)
	}

	if resp.StatusCode != http.StatusNoContent {
		t.Fatalf("Expected status %d, got %d", http.StatusNoContent, resp.StatusCode)
	}

	for h, v := range corsHeaders {
		if resp.Header.Get(h) != v {
			t.Fatalf("Expected %q for header %q, got %q", v, h, resp.Header.Get(h))
		}
	}
}

func TestRespond(t *testing.T) {
	cases := []struct {
		response interface{}
		expected string
	}{
		{
			response: &queryData{
				ResultType: promql.ValueTypeMatrix,
				Result: promql.Matrix{
					promql.Series{
						Points: []promql.Point{{V: 1, T: 1000}},
						Metric: labels.FromStrings("__name__", "foo"),
					},
				},
			},
			expected: `{"status":"success","data":{"resultType":"matrix","result":[{"metric":{"__name__":"foo"},"values":[[1,"1"]]}]}}`,
		},
		{
			response: promql.Point{V: 0, T: 0},
			expected: `{"status":"success","data":[0,"0"]}`,
		},
		{
			response: promql.Point{V: 20, T: 1},
			expected: `{"status":"success","data":[0.001,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 10},
			expected: `{"status":"success","data":[0.010,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 100},
			expected: `{"status":"success","data":[0.100,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 1001},
			expected: `{"status":"success","data":[1.001,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 1010},
			expected: `{"status":"success","data":[1.010,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 1100},
			expected: `{"status":"success","data":[1.100,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: 12345678123456555},
			expected: `{"status":"success","data":[12345678123456.555,"20"]}`,
		},
		{
			response: promql.Point{V: 20, T: -1},
			expected: `{"status":"success","data":[-0.001,"20"]}`,
		},
		{
			response: promql.Point{V: math.NaN(), T: 0},
			expected: `{"status":"success","data":[0,"NaN"]}`,
		},
		{
			response: promql.Point{V: math.Inf(1), T: 0},
			expected: `{"status":"success","data":[0,"+Inf"]}`,
		},
		{
			response: promql.Point{V: math.Inf(-1), T: 0},
			expected: `{"status":"success","data":[0,"-Inf"]}`,
		},
		{
			response: promql.Point{V: 1.2345678e6, T: 0},
			expected: `{"status":"success","data":[0,"1234567.8"]}`,
		},
		{
			response: promql.Point{V: 1.2345678e-6, T: 0},
			expected: `{"status":"success","data":[0,"0.0000012345678"]}`,
		},
		{
			response: promql.Point{V: 1.2345678e-67, T: 0},
			expected: `{"status":"success","data":[0,"1.2345678e-67"]}`,
		},
	}

	for _, c := range cases {
		s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			respond(w, c.response)
		}))
		defer s.Close()

		resp, err := http.Get(s.URL)
		if err != nil {
			t.Fatalf("Error on test request: %s", err)
		}
		body, err := ioutil.ReadAll(resp.Body)
		defer resp.Body.Close()
		if err != nil {
			t.Fatalf("Error reading response body: %s", err)
		}

		if string(body) != c.expected {
			t.Fatalf("Expected response \n%v\n but got \n%v\n", c.expected, string(body))
		}
	}
}

// This is a global to avoid the benchmark being optimized away.
var testResponseWriter = httptest.ResponseRecorder{}

func BenchmarkRespond(b *testing.B) {
	b.ReportAllocs()
	points := []promql.Point{}
	for i := 0; i < 10000; i++ {
		points = append(points, promql.Point{V: float64(i * 1000000), T: int64(i)})
	}
	response := &queryData{
		ResultType: promql.ValueTypeMatrix,
		Result: promql.Matrix{
			promql.Series{
				Points: points,
				Metric: nil,
			},
		},
	}
	b.ResetTimer()
	for n := 0; n < b.N; n++ {
		respond(&testResponseWriter, response)
	}
}