Refactor tests to work with new protobuf library.

Signed-off-by: SuperQ <superq@gmail.com>

prometheus/counter_test.go

@@ -61,8 +61,10 @@ func TestCounterAdd(t *testing.T) {
 	m := &dto.Metric{}
 	counter.Write(m)
 
-	if expected, got := `label:<name:"a" value:"1" > label:<name:"b" value:"2" > counter:<value:67.42 > `, m.String(); expected != got {
+	want := `label:{name:"a" value:"1"} label:{name:"b" value:"2"} counter:{value:67.42}`
-		t.Errorf("expected %q, got %q", expected, got)
+
+	if err := compareProtoAndMetric(want, m); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
 }
 
@@ -164,8 +166,10 @@ func TestCounterAddInf(t *testing.T) {
 	m := &dto.Metric{}
 	counter.Write(m)
 
-	if expected, got := `counter:<value:inf > `, m.String(); expected != got {
+	want := `counter:{value:inf}`
-		t.Errorf("expected %q, got %q", expected, got)
+
+	if err := compareProtoAndMetric(want, m); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
 }
 
@@ -188,8 +192,10 @@ func TestCounterAddLarge(t *testing.T) {
 	m := &dto.Metric{}
 	counter.Write(m)
 
-	if expected, got := fmt.Sprintf("counter:<value:%0.16e > ", large), m.String(); expected != got {
+	want := fmt.Sprintf("counter:{value:%0.16e}", large)
-		t.Errorf("expected %q, got %q", expected, got)
+
+	if err := compareProtoAndMetric(want, m); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
 }
 
@@ -210,8 +216,10 @@ func TestCounterAddSmall(t *testing.T) {
 	m := &dto.Metric{}
 	counter.Write(m)
 
-	if expected, got := fmt.Sprintf("counter:<value:%0.0e > ", small), m.String(); expected != got {
+	want := fmt.Sprintf("counter:{value:%0.0e}", small)
-		t.Errorf("expected %q, got %q", expected, got)
+
+	if err := compareProtoAndMetric(want, m); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
 }
 

prometheus/example_metricvec_test.go

@@ -14,13 +14,13 @@
 package prometheus_test
 
 import (
-	"fmt"
+	"testing"
 
 	"google.golang.org/protobuf/proto"
 
-	dto "github.com/prometheus/client_model/go"
-
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	dto "github.com/prometheus/client_model/go"
 )
 
 // Info implements an info pseudo-metric, which is modeled as a Gauge that
@@ -106,7 +106,7 @@ func (v *InfoVec) MustCurryWith(labels prometheus.Labels) *InfoVec {
 	return vec
 }
 
-func ExampleMetricVec() {
+func TestExampleMetricVec(t *testing.T) {
 	infoVec := NewInfoVec(
 		"library_version_info",
 		"Versions of the libraries used in this binary.",
@@ -126,8 +126,40 @@ func ExampleMetricVec() {
 	if err != nil || len(metricFamilies) != 1 {
 		panic("unexpected behavior of custom test registry")
 	}
-	fmt.Println(metricFamilies[0].String())
 
-	// Output:
+	want := `
-	// name:"library_version_info" help:"Versions of the libraries used in this binary." type:GAUGE metric:<label:<name:"library" value:"k8s.io/client-go" > label:<name:"version" value:"0.18.8" > gauge:<value:1 > > metric:<label:<name:"library" value:"prometheus/client_golang" > label:<name:"version" value:"1.7.1" > gauge:<value:1 > >
+	name: "library_version_info"
+	help: "Versions of the libraries used in this binary."
+	type: GAUGE
+	metric: {
+	  label: {
+	    name: "library"
+	    value: "k8s.io/client-go"
+	  }
+	  label: {
+	    name: "version"
+	    value: "0.18.8"
+	  }
+	  gauge: {
+	    value: 1
+	  }
+	}
+	metric: {
+	  label: {
+	    name: "library"
+	    value: "prometheus/client_golang"
+	  }
+	  label: {
+	    name: "version"
+	    value: "1.7.1"
+	  }
+	  gauge: {
+	    value: 1
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetricFamily(want, metricFamilies[0]); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }

prometheus/examples_test.go

@@ -21,13 +21,16 @@ import (
 	"net/http"
 	"runtime"
 	"strings"
+	"testing"
 	"time"
 
 	dto "github.com/prometheus/client_model/go"
 	"github.com/prometheus/common/expfmt"
+	"google.golang.org/protobuf/encoding/prototext"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/prometheus/client_golang/prometheus/testutil"
 )
 
 func ExampleGauge() {
@@ -302,7 +305,7 @@ func ExampleRegister() {
 	// taskCounterForWorker2001 registered.
 }
 
-func ExampleSummary() {
+func TestExampleSummary(t *testing.T) {
 	temps := prometheus.NewSummary(prometheus.SummaryOpts{
 		Name:       "pond_temperature_celsius",
 		Help:       "The temperature of the frog pond.",
@@ -319,13 +322,32 @@ func ExampleSummary() {
 	// internally).
 	metric := &dto.Metric{}
 	temps.Write(metric)
-	fmt.Println(metric.String())
 
-	// Output:
+	want := `
-	// summary:<sample_count:1000 sample_sum:29969.50000000001 quantile:<quantile:0.5 value:31.1 > quantile:<quantile:0.9 value:41.3 > quantile:<quantile:0.99 value:41.9 > >
+	summary:  {
+	  sample_count:  1000
+	  sample_sum:  29969.50000000001
+	  quantile:  {
+	    quantile:  0.5
+	    value:  31.1
+	  }
+	  quantile:  {
+	    quantile:  0.9
+	    value:  41.3
+	  }
+	  quantile:  {
+	    quantile:  0.99
+	    value:  41.9
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
-func ExampleSummaryVec() {
+func TestExampleSummaryVec(t *testing.T) {
 	temps := prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
 			Name:       "pond_temperature_celsius",
@@ -354,13 +376,86 @@ func ExampleSummaryVec() {
 	if err != nil || len(metricFamilies) != 1 {
 		panic("unexpected behavior of custom test registry")
 	}
-	fmt.Println(metricFamilies[0].String())
+	fmt.Println(prototext.Format(metricFamilies[0]))
 
-	// Output:
+	want := `
-	// name:"pond_temperature_celsius" help:"The temperature of the frog pond." type:SUMMARY metric:<label:<name:"species" value:"leiopelma-hochstetteri" > summary:<sample_count:0 sample_sum:0 quantile:<quantile:0.5 value:nan > quantile:<quantile:0.9 value:nan > quantile:<quantile:0.99 value:nan > > > metric:<label:<name:"species" value:"lithobates-catesbeianus" > summary:<sample_count:1000 sample_sum:31956.100000000017 quantile:<quantile:0.5 value:32.4 > quantile:<quantile:0.9 value:41.4 > quantile:<quantile:0.99 value:41.9 > > > metric:<label:<name:"species" value:"litoria-caerulea" > summary:<sample_count:1000 sample_sum:29969.50000000001 quantile:<quantile:0.5 value:31.1 > quantile:<quantile:0.9 value:41.3 > quantile:<quantile:0.99 value:41.9 > > >
+	name: "pond_temperature_celsius"
+	help: "The temperature of the frog pond."
+	type: SUMMARY
+	metric: {
+	  label: {
+	    name: "species"
+	    value: "leiopelma-hochstetteri"
+	  }
+	  summary: {
+	    sample_count: 0
+	    sample_sum: 0
+	    quantile: {
+	      quantile: 0.5
+	      value: nan
+	    }
+	    quantile: {
+	      quantile: 0.9
+	      value: nan
+	    }
+	    quantile: {
+	      quantile: 0.99
+	      value: nan
+	    }
+	  }
+	}
+	metric: {
+	  label: {
+	    name: "species"
+	    value: "lithobates-catesbeianus"
+	  }
+	  summary: {
+	    sample_count: 1000
+	    sample_sum: 31956.100000000017
+	    quantile: {
+	      quantile: 0.5
+	      value: 32.4
+	    }
+	    quantile: {
+	      quantile: 0.9
+	      value: 41.4
+	    }
+	    quantile: {
+	      quantile: 0.99
+	      value: 41.9
+	    }
+	  }
+	}
+	metric: {
+	  label: {
+	    name: "species"
+	    value: "litoria-caerulea"
+	  }
+	  summary: {
+	    sample_count: 1000
+	    sample_sum: 29969.50000000001
+	    quantile: {
+	      quantile: 0.5
+	      value: 31.1
+	    }
+	    quantile: {
+	      quantile: 0.9
+	      value: 41.3
+	    }
+	    quantile: {
+	      quantile: 0.99
+	      value: 41.9
+	    }
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetricFamily(want, metricFamilies[0]); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
-func ExampleNewConstSummary() {
+func TestExampleNewConstSummary(t *testing.T) {
 	desc := prometheus.NewDesc(
 		"http_request_duration_seconds",
 		"A summary of the HTTP request durations.",
@@ -381,13 +476,41 @@ func ExampleNewConstSummary() {
 	// internally).
 	metric := &dto.Metric{}
 	s.Write(metric)
-	fmt.Println(metric.String())
+	fmt.Println(prototext.Format(metric))
 
-	// Output:
+	want := `
-	// label:<name:"code" value:"200" > label:<name:"method" value:"get" > label:<name:"owner" value:"example" > summary:<sample_count:4711 sample_sum:403.34 quantile:<quantile:0.5 value:42.3 > quantile:<quantile:0.9 value:323.3 > >
+	label:  {
+	  name:  "code"
+	  value:  "200"
+	}
+	label:  {
+	  name:  "method"
+	  value:  "get"
+	}
+	label:  {
+	  name:  "owner"
+	  value:  "example"
+	}
+	summary:  {
+	  sample_count:  4711
+	  sample_sum:  403.34
+	  quantile:  {
+	    quantile:  0.5
+	    value:  42.3
+	  }
+	  quantile:  {
+	    quantile:  0.9
+	    value:  323.3
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
-func ExampleHistogram() {
+func TestExampleHistogram(t *testing.T) {
 	temps := prometheus.NewHistogram(prometheus.HistogramOpts{
 		Name:    "pond_temperature_celsius",
 		Help:    "The temperature of the frog pond.", // Sorry, we can't measure how badly it smells.
@@ -404,13 +527,41 @@ func ExampleHistogram() {
 	// internally).
 	metric := &dto.Metric{}
 	temps.Write(metric)
-	fmt.Println(metric.String())
+	fmt.Println(prototext.Format(metric))
 
-	// Output:
+	want := `
-	// histogram:<sample_count:1000 sample_sum:29969.50000000001 bucket:<cumulative_count:192 upper_bound:20 > bucket:<cumulative_count:366 upper_bound:25 > bucket:<cumulative_count:501 upper_bound:30 > bucket:<cumulative_count:638 upper_bound:35 > bucket:<cumulative_count:816 upper_bound:40 > >
+	histogram: {
+	  sample_count: 1000
+	  sample_sum: 29969.50000000001
+	  bucket: {
+	    cumulative_count: 192
+	    upper_bound: 20
+	  }
+	  bucket: {
+	    cumulative_count: 366
+	    upper_bound: 25
+	  }
+	  bucket: {
+	    cumulative_count: 501
+	    upper_bound: 30
+	  }
+	  bucket: {
+	    cumulative_count: 638
+	    upper_bound: 35
+	  }
+	  bucket: {
+	    cumulative_count: 816
+	    upper_bound: 40
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
-func ExampleNewConstHistogram() {
+func TestExampleNewConstHistogram(t *testing.T) {
 	desc := prometheus.NewDesc(
 		"http_request_duration_seconds",
 		"A histogram of the HTTP request durations.",
@@ -431,13 +582,49 @@ func ExampleNewConstHistogram() {
 	// internally).
 	metric := &dto.Metric{}
 	h.Write(metric)
-	fmt.Println(metric.String())
+	fmt.Println(prototext.Format(metric))
 
-	// Output:
+	want := `
-	// label:<name:"code" value:"200" > label:<name:"method" value:"get" > label:<name:"owner" value:"example" > histogram:<sample_count:4711 sample_sum:403.34 bucket:<cumulative_count:121 upper_bound:25 > bucket:<cumulative_count:2403 upper_bound:50 > bucket:<cumulative_count:3221 upper_bound:100 > bucket:<cumulative_count:4233 upper_bound:200 > >
+	label: {
+	  name: "code"
+	  value: "200"
+	}
+	label: {
+	  name: "method"
+	  value: "get"
+	}
+	label:  {
+	  name: "owner"
+	  value: "example"
+	}
+	histogram:  {
+	  sample_count: 4711
+	  sample_sum: 403.34
+	  bucket: {
+	    cumulative_count: 121
+	    upper_bound: 25
+	  }
+	  bucket: {
+	    cumulative_count: 2403
+	    upper_bound: 50
+	  }
+	  bucket: {
+	    cumulative_count: 3221
+	    upper_bound: 100
+	  }
+	  bucket: {
+	    cumulative_count: 4233
+	    upper_bound: 200
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
-func ExampleNewConstHistogram_WithExemplar() {
+func TestExampleNewConstHistogram_WithExemplar(t *testing.T) {
 	desc := prometheus.NewDesc(
 		"http_request_duration_seconds",
 		"A histogram of the HTTP request durations.",
@@ -469,10 +656,86 @@ func ExampleNewConstHistogram_WithExemplar() {
 	// internally).
 	metric := &dto.Metric{}
 	h.Write(metric)
-	fmt.Println(metric.String())
+	fmt.Println(prototext.Format(metric))
 
-	// Output:
+	want := `
-	// label:<name:"code" value:"200" > label:<name:"method" value:"get" > label:<name:"owner" value:"example" > histogram:<sample_count:4711 sample_sum:403.34 bucket:<cumulative_count:121 upper_bound:25 exemplar:<label:<name:"testName" value:"testVal" > value:24 timestamp:<seconds:1136214245 > > > bucket:<cumulative_count:2403 upper_bound:50 exemplar:<label:<name:"testName" value:"testVal" > value:42 timestamp:<seconds:1136214245 > > > bucket:<cumulative_count:3221 upper_bound:100 exemplar:<label:<name:"testName" value:"testVal" > value:89 timestamp:<seconds:1136214245 > > > bucket:<cumulative_count:4233 upper_bound:200 exemplar:<label:<name:"testName" value:"testVal" > value:157 timestamp:<seconds:1136214245 > > > >
+	label: {
+	  name: "code"
+	  value: "200"
+	}
+	label: {
+	  name: "method"
+	  value: "get"
+	}
+	label: {
+	  name: "owner"
+	  value: "example"
+	}
+	histogram: {
+	  sample_count: 4711
+	  sample_sum: 403.34
+	  bucket: {
+	    cumulative_count: 121
+	    upper_bound: 25
+	    exemplar: {
+	      label: {
+	        name: "testName"
+	        value: "testVal"
+	      }
+	      value: 24
+	      timestamp: {
+	        seconds: 1136214245
+	      }
+	    }
+	  }
+	  bucket: {
+	    cumulative_count: 2403
+	    upper_bound: 50
+	    exemplar: {
+	      label: {
+	        name: "testName"
+	        value: "testVal"
+	      }
+	      value: 42
+	      timestamp: {
+	        seconds: 1136214245
+	      }
+	    }
+	  }
+	  bucket: {
+	    cumulative_count: 3221
+	    upper_bound: 100
+	    exemplar: {
+	      label: {
+	        name: "testName"
+	        value: "testVal"
+	      }
+	      value: 89
+	      timestamp: {
+	        seconds: 1136214245
+	      }
+	    }
+	  }
+	  bucket: {
+	    cumulative_count: 4233
+	    upper_bound: 200
+	    exemplar: {
+	      label: {
+	        name: "testName"
+	        value: "testVal"
+	      }
+	      value: 157
+	      timestamp: {
+	        seconds: 1136214245
+	      }
+	    }
+	  }
+	}
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }
 
 func ExampleAlreadyRegisteredError() {
@@ -589,7 +852,7 @@ temperature_kelvin 4.5
 	// temperature_kelvin{location="outside"} 273.14
 	// temperature_kelvin{location="somewhere else"} 4.5
 	// ----------
-	// collected metric "temperature_kelvin" { label:<name:"location" value:"outside" > gauge:<value:265.3 > } was collected before with the same name and label values
+	// collected metric "temperature_kelvin" { label:{name:"location" value:"outside"} gauge:{value:265.3}} was collected before with the same name and label values
 	// # HELP humidity_percent Humidity in %.
 	// # TYPE humidity_percent gauge
 	// humidity_percent{location="inside"} 33.2
@@ -601,7 +864,7 @@ temperature_kelvin 4.5
 	// temperature_kelvin{location="outside"} 273.14
 }
 
-func ExampleNewMetricWithTimestamp() {
+func TestExampleNewMetricWithTimestamp(t *testing.T) {
 	desc := prometheus.NewDesc(
 		"temperature_kelvin",
 		"Current temperature in Kelvin.",
@@ -625,8 +888,16 @@ func ExampleNewMetricWithTimestamp() {
 	// internally).
 	metric := &dto.Metric{}
 	s.Write(metric)
-	fmt.Println(metric.String())
+	fmt.Println(prototext.Format(metric))
 
-	// Output:
+	want := `
-	// gauge:<value:298.15 > timestamp_ms:1257894000012
+	gauge: {
+	  value: 298.15
+	}
+	timestamp_ms: 1257894000012
+	`
+
+	if err := testutil.CompareProtoAndMetric(want, metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
+	}
 }

prometheus/expvar_collector_test.go

@@ -15,16 +15,16 @@ package prometheus_test
 
 import (
 	"expvar"
-	"fmt"
-	"sort"
 	"strings"
+	"testing"
 
 	dto "github.com/prometheus/client_model/go"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
 )
 
-func ExampleNewExpvarCollector() {
+func TestExampleNewExpvarCollector(t *testing.T) {
 	expvarCollector := prometheus.NewExpvarCollector(map[string]*prometheus.Desc{
 		"memstats": prometheus.NewDesc(
 			"expvar_memstats",
@@ -70,7 +70,6 @@ func ExampleNewExpvarCollector() {
 	// "http-request-count": {"200": {"POST": 11, "GET": 212}, "404": {"POST": 3, "GET": 13}}
 
 	// Let's see what the scrape would yield, but exclude the memstats metrics.
-	metricStrings := []string{}
 	metric := dto.Metric{}
 	metricChan := make(chan prometheus.Metric)
 	go func() {
@@ -79,19 +78,20 @@ func ExampleNewExpvarCollector() {
 	}()
 	for m := range metricChan {
 		if !strings.Contains(m.Desc().String(), "expvar_memstats") {
-			metric.Reset()
 			m.Write(&metric)
-			metricStrings = append(metricStrings, metric.String())
 		}
 	}
-	sort.Strings(metricStrings)
+
-	for _, s := range metricStrings {
+	want := `label:{name:"code" value:"200"} label:{name:"method" value:"GET"} untyped:{value:212}`
-		fmt.Println(strings.TrimRight(s, " "))
+
+	if err := testutil.CompareProtoAndMetric(want, &metric); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
+
 	// Output:
-	// label:<name:"code" value:"200" > label:<name:"method" value:"GET" > untyped:<value:212 >
+	// label:{name:"code" value:"200"} label:{name:"method" value:"GET"} untyped:{value:212}
-	// label:<name:"code" value:"200" > label:<name:"method" value:"POST" > untyped:<value:11 >
+	// label:{name:"code" value:"200"} label:{name:"method" value:"POST"} untyped:{value:11}
-	// label:<name:"code" value:"404" > label:<name:"method" value:"GET" > untyped:<value:13 >
+	// label:{name:"code" value:"404"} label:{name:"method" value:"GET"} untyped:{value:13}
-	// label:<name:"code" value:"404" > label:<name:"method" value:"POST" > untyped:<value:3 >
+	// label:{name:"code" value:"404"} label:{name:"method" value:"POST"} untyped:{value:3}
-	// untyped:<value:42 >
+	// untyped:{value:42}
 }

prometheus/gauge_test.go

@@ -177,8 +177,10 @@ func TestGaugeFunc(t *testing.T) {
 	m := &dto.Metric{}
 	gf.Write(m)
 
-	if expected, got := `label:<name:"a" value:"1" > label:<name:"b" value:"2" > gauge:<value:3.1415 > `, m.String(); expected != got {
+	want := `label:{name:"a" value:"1"} label:{name:"b" value:"2"} gauge:{value:3.1415}`
-		t.Errorf("expected %q, got %q", expected, got)
+
+	if err := compareProtoAndMetric(want, m); err != nil {
+		t.Errorf("Summary didn't match: %s", err)
 	}
 }
 

prometheus/histogram_test.go

@@ -483,19 +483,19 @@ func TestNativeHistogram(t *testing.T) {
 			name:         "no sparse buckets",
 			observations: []float64{1, 2, 3},
 			factor:       1,
-			want:         `sample_count:3 sample_sum:6 bucket:<cumulative_count:0 upper_bound:0.005 > bucket:<cumulative_count:0 upper_bound:0.01 > bucket:<cumulative_count:0 upper_bound:0.025 > bucket:<cumulative_count:0 upper_bound:0.05 > bucket:<cumulative_count:0 upper_bound:0.1 > bucket:<cumulative_count:0 upper_bound:0.25 > bucket:<cumulative_count:0 upper_bound:0.5 > bucket:<cumulative_count:1 upper_bound:1 > bucket:<cumulative_count:2 upper_bound:2.5 > bucket:<cumulative_count:3 upper_bound:5 > bucket:<cumulative_count:3 upper_bound:10 > `, // Has conventional buckets because there are no sparse buckets.
+			want:         `histogram{sample_count:3 sample_sum:6 bucket:{cumulative_count:0 upper_bound:0.005} bucket:{cumulative_count:0 upper_bound:0.01} bucket:{cumulative_count:0 upper_bound:0.025} bucket:{cumulative_count:0 upper_bound:0.05} bucket:{cumulative_count:0 upper_bound:0.1} bucket:{cumulative_count:0 upper_bound:0.25} bucket:{cumulative_count:0 upper_bound:0.5} bucket:{cumulative_count:1 upper_bound:1} bucket:{cumulative_count:2 upper_bound:2.5} bucket:{cumulative_count:3 upper_bound:5} bucket:{cumulative_count:3 upper_bound:10}}`, // Has conventional buckets because there are no sparse buckets.
 		},
 		{
 			name:         "factor 1.1 results in schema 3",
 			observations: []float64{0, 1, 2, 3},
 			factor:       1.1,
-			want:         `sample_count:4 sample_sum:6 schema:3 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:1 > positive_span:<offset:7 length:1 > positive_span:<offset:4 length:1 > positive_delta:1 positive_delta:0 positive_delta:0 `,
+			want:         `histogram{sample_count:4 sample_sum:6 schema:3 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:1} positive_span:{offset:7 length:1} positive_span:{offset:4 length:1} positive_delta:1 positive_delta:0 positive_delta:0}`,
 		},
 		{
 			name:         "factor 1.2 results in schema 2",
 			observations: []float64{0, 1, 1.2, 1.4, 1.8, 2},
 			factor:       1.2,
-			want:         `sample_count:6 sample_sum:7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 `,
+			want:         `histogram{sample_count:6 sample_sum:7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2}`,
 		},
 		{
 			name: "factor 4 results in schema -1",
@@ -506,7 +506,7 @@ func TestNativeHistogram(t *testing.T) {
 				33.33, // Bucket 3: (16, 64]
 			},
 			factor: 4,
-			want:   `sample_count:10 sample_sum:62.83 schema:-1 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:<offset:0 length:4 > positive_delta:2 positive_delta:2 positive_delta:-1 positive_delta:-2 `,
+			want:   `histogram{sample_count:10 sample_sum:62.83 schema:-1 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:{offset:0 length:4} positive_delta:2 positive_delta:2 positive_delta:-1 positive_delta:-2}`,
 		},
 		{
 			name: "factor 17 results in schema -2",
@@ -516,58 +516,58 @@ func TestNativeHistogram(t *testing.T) {
 				33.33, // Bucket 2: (16, 256]
 			},
 			factor: 17,
-			want:   `sample_count:10 sample_sum:62.83 schema:-2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:<offset:0 length:3 > positive_delta:2 positive_delta:5 positive_delta:-6 `,
+			want:   `histogram{sample_count:10 sample_sum:62.83 schema:-2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:{offset:0 length:3} positive_delta:2 positive_delta:5 positive_delta:-6}`,
 		},
 		{
 			name:         "negative buckets",
 			observations: []float64{0, -1, -1.2, -1.4, -1.8, -2},
 			factor:       1.2,
-			want:         `sample_count:6 sample_sum:-7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:<offset:0 length:5 > negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2 `,
+			want:         `histogram{sample_count:6 sample_sum:-7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:{offset:0 length:5} negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2}`,
 		},
 		{
 			name:         "negative and positive buckets",
 			observations: []float64{0, -1, -1.2, -1.4, -1.8, -2, 1, 1.2, 1.4, 1.8, 2},
 			factor:       1.2,
-			want:         `sample_count:11 sample_sum:0 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:<offset:0 length:5 > negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 `,
+			want:         `histogram{sample_count:11 sample_sum:0 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:{offset:0 length:5} negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2}`,
 		},
 		{
 			name:          "wide zero bucket",
 			observations:  []float64{0, -1, -1.2, -1.4, -1.8, -2, 1, 1.2, 1.4, 1.8, 2},
 			factor:        1.2,
 			zeroThreshold: 1.4,
-			want:          `sample_count:11 sample_sum:0 schema:2 zero_threshold:1.4 zero_count:7 negative_span:<offset:4 length:1 > negative_delta:2 positive_span:<offset:4 length:1 > positive_delta:2 `,
+			want:          `histogram{sample_count:11 sample_sum:0 schema:2 zero_threshold:1.4 zero_count:7 negative_span:{offset:4 length:1} negative_delta:2 positive_span:{offset:4 length:1} positive_delta:2}`,
 		},
 		{
 			name:         "NaN observation",
 			observations: []float64{0, 1, 1.2, 1.4, 1.8, 2, math.NaN()},
 			factor:       1.2,
-			want:         `sample_count:7 sample_sum:nan schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 `,
+			want:         `histogram{sample_count:7 sample_sum:nan schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2}`,
 		},
 		{
 			name:         "+Inf observation",
 			observations: []float64{0, 1, 1.2, 1.4, 1.8, 2, math.Inf(+1)},
 			factor:       1.2,
-			want:         `sample_count:7 sample_sum:inf schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:5 > positive_span:<offset:4092 length:1 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 positive_delta:-1 `,
+			want:         `histogram{sample_count:7 sample_sum:inf schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:5} positive_span:{offset:4092 length:1} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 positive_delta:-1}`,
 		},
 		{
 			name:         "-Inf observation",
 			observations: []float64{0, 1, 1.2, 1.4, 1.8, 2, math.Inf(-1)},
 			factor:       1.2,
-			want:         `sample_count:7 sample_sum:-inf schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:<offset:4097 length:1 > negative_delta:1 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 `,
+			want:         `histogram{sample_count:7 sample_sum:-inf schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:{offset:4097 length:1} negative_delta:1 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2}`,
 		},
 		{
 			name:         "limited buckets but nothing triggered",
 			observations: []float64{0, 1, 1.2, 1.4, 1.8, 2},
 			factor:       1.2,
 			maxBuckets:   4,
-			want:         `sample_count:6 sample_sum:7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2 `,
+			want:         `histogram{sample_count:6 sample_sum:7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:-1 positive_delta:2 positive_delta:-2 positive_delta:2}`,
 		},
 		{
 			name:         "buckets limited by halving resolution",
 			observations: []float64{0, 1, 1.1, 1.2, 1.4, 1.8, 2, 3},
 			factor:       1.2,
 			maxBuckets:   4,
-			want:         `sample_count:8 sample_sum:11.5 schema:1 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:<offset:0 length:5 > positive_delta:1 positive_delta:2 positive_delta:-1 positive_delta:-2 positive_delta:1 `,
+			want:         `histogram{sample_count:8 sample_sum:11.5 schema:1 zero_threshold:2.938735877055719e-39 zero_count:1 positive_span:{offset:0 length:5} positive_delta:1 positive_delta:2 positive_delta:-1 positive_delta:-2 positive_delta:1}`,
 		},
 		{
 			name:             "buckets limited by widening the zero bucket",
@@ -575,7 +575,7 @@ func TestNativeHistogram(t *testing.T) {
 			factor:           1.2,
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
-			want:             `sample_count:8 sample_sum:11.5 schema:2 zero_threshold:1 zero_count:2 positive_span:<offset:1 length:7 > positive_delta:1 positive_delta:1 positive_delta:-2 positive_delta:2 positive_delta:-2 positive_delta:0 positive_delta:1 `,
+			want:             `histogram{sample_count:8 sample_sum:11.5 schema:2 zero_threshold:1 zero_count:2 positive_span:{offset:1 length:7} positive_delta:1 positive_delta:1 positive_delta:-2 positive_delta:2 positive_delta:-2 positive_delta:0 positive_delta:1}`,
 		},
 		{
 			name:             "buckets limited by widening the zero bucket twice",
@@ -583,7 +583,7 @@ func TestNativeHistogram(t *testing.T) {
 			factor:           1.2,
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
-			want:             `sample_count:9 sample_sum:15.5 schema:2 zero_threshold:1.189207115002721 zero_count:3 positive_span:<offset:2 length:7 > positive_delta:2 positive_delta:-2 positive_delta:2 positive_delta:-2 positive_delta:0 positive_delta:1 positive_delta:0 `,
+			want:             `histogram{sample_count:9 sample_sum:15.5 schema:2 zero_threshold:1.189207115002721 zero_count:3 positive_span:{offset:2 length:7} positive_delta:2 positive_delta:-2 positive_delta:2 positive_delta:-2 positive_delta:0 positive_delta:1 positive_delta:0}`,
 		},
 		{
 			name:             "buckets limited by reset",
@@ -592,21 +592,21 @@ func TestNativeHistogram(t *testing.T) {
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
 			minResetDuration: 5 * time.Minute,
-			want:             `sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:<offset:7 length:2 > positive_delta:1 positive_delta:0 `,
+			want:             `histogram{sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:{offset:7 length:2} positive_delta:1 positive_delta:0}`,
 		},
 		{
 			name:         "limited buckets but nothing triggered, negative observations",
 			observations: []float64{0, -1, -1.2, -1.4, -1.8, -2},
 			factor:       1.2,
 			maxBuckets:   4,
-			want:         `sample_count:6 sample_sum:-7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:<offset:0 length:5 > negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2 `,
+			want:         `histogram{sample_count:6 sample_sum:-7.4 schema:2 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:{offset:0 length:5} negative_delta:1 negative_delta:-1 negative_delta:2 negative_delta:-2 negative_delta:2}`,
 		},
 		{
 			name:         "buckets limited by halving resolution, negative observations",
 			observations: []float64{0, -1, -1.1, -1.2, -1.4, -1.8, -2, -3},
 			factor:       1.2,
 			maxBuckets:   4,
-			want:         `sample_count:8 sample_sum:-11.5 schema:1 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:<offset:0 length:5 > negative_delta:1 negative_delta:2 negative_delta:-1 negative_delta:-2 negative_delta:1 `,
+			want:         `histogram{sample_count:8 sample_sum:-11.5 schema:1 zero_threshold:2.938735877055719e-39 zero_count:1 negative_span:{offset:0 length:5} negative_delta:1 negative_delta:2 negative_delta:-1 negative_delta:-2 negative_delta:1}`,
 		},
 		{
 			name:             "buckets limited by widening the zero bucket, negative observations",
@@ -614,7 +614,7 @@ func TestNativeHistogram(t *testing.T) {
 			factor:           1.2,
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
-			want:             `sample_count:8 sample_sum:-11.5 schema:2 zero_threshold:1 zero_count:2 negative_span:<offset:1 length:7 > negative_delta:1 negative_delta:1 negative_delta:-2 negative_delta:2 negative_delta:-2 negative_delta:0 negative_delta:1 `,
+			want:             `histogram{sample_count:8 sample_sum:-11.5 schema:2 zero_threshold:1 zero_count:2 negative_span:{offset:1 length:7} negative_delta:1 negative_delta:1 negative_delta:-2 negative_delta:2 negative_delta:-2 negative_delta:0 negative_delta:1}`,
 		},
 		{
 			name:             "buckets limited by widening the zero bucket twice, negative observations",
@@ -622,7 +622,7 @@ func TestNativeHistogram(t *testing.T) {
 			factor:           1.2,
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
-			want:             `sample_count:9 sample_sum:-15.5 schema:2 zero_threshold:1.189207115002721 zero_count:3 negative_span:<offset:2 length:7 > negative_delta:2 negative_delta:-2 negative_delta:2 negative_delta:-2 negative_delta:0 negative_delta:1 negative_delta:0 `,
+			want:             `histogram{sample_count:9 sample_sum:-15.5 schema:2 zero_threshold:1.189207115002721 zero_count:3 negative_span:{offset:2 length:7} negative_delta:2 negative_delta:-2 negative_delta:2 negative_delta:-2 negative_delta:0 negative_delta:1 negative_delta:0}`,
 		},
 		{
 			name:             "buckets limited by reset, negative observations",
@@ -631,7 +631,7 @@ func TestNativeHistogram(t *testing.T) {
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
 			minResetDuration: 5 * time.Minute,
-			want:             `sample_count:2 sample_sum:-7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 negative_span:<offset:7 length:2 > negative_delta:1 negative_delta:0 `,
+			want:             `histogram{sample_count:2 sample_sum:-7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 negative_span:{offset:7 length:2} negative_delta:1 negative_delta:0}`,
 		},
 		{
 			name:             "buckets limited by halving resolution, then reset",
@@ -639,7 +639,7 @@ func TestNativeHistogram(t *testing.T) {
 			factor:           1.2,
 			maxBuckets:       4,
 			minResetDuration: 9 * time.Minute,
-			want:             `sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:<offset:7 length:2 > positive_delta:1 positive_delta:0 `,
+			want:             `histogram{sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:{offset:7 length:2} positive_delta:1 positive_delta:0}`,
 		},
 		{
 			name:             "buckets limited by widening the zero bucket, then reset",
@@ -648,7 +648,7 @@ func TestNativeHistogram(t *testing.T) {
 			maxBuckets:       4,
 			maxZeroThreshold: 1.2,
 			minResetDuration: 9 * time.Minute,
-			want:             `sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:<offset:7 length:2 > positive_delta:1 positive_delta:0 `,
+			want:             `histogram{sample_count:2 sample_sum:7 schema:2 zero_threshold:2.938735877055719e-39 zero_count:0 positive_span:{offset:7 length:2} positive_delta:1 positive_delta:0}`,
 		},
 	}
 
@@ -676,9 +676,8 @@ func TestNativeHistogram(t *testing.T) {
 			if err := his.Write(m); err != nil {
 				t.Fatal("unexpected error writing metric", err)
 			}
-			got := m.Histogram.String()
+			if err := compareProtoAndMetric(s.want, m); err != nil {
-			if s.want != got {
+				t.Errorf("want histogram %q, got %q", s.want, m)
-				t.Errorf("want histogram %q, got %q", s.want, got)
 			}
 		})
 	}

prometheus/metric.go

@@ -14,7 +14,9 @@
 package prometheus
 
 import (
+	"bytes"
 	"errors"
+	"fmt"
 	"math"
 	"sort"
 	"strings"
@@ -22,6 +24,7 @@ import (
 
 	dto "github.com/prometheus/client_model/go"
 	"github.com/prometheus/common/model"
+	"google.golang.org/protobuf/encoding/prototext"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -252,3 +255,33 @@ func MustNewMetricWithExemplars(m Metric, exemplars ...Exemplar) Metric {
 	}
 	return ret
 }
+
+// compareProtoAndMetric compares a text proto to a Metric.
+//
+// It jumps through a few hoops because the current protobuf
+// implementation is deliberately creating an unstable formatting for the text
+// representation. So this takes the text representation of the expected
+// Metric and unmarshals it into a proto message object first. Then it
+// marshals both the expected and the got proto message into a binary protobuf,
+// which it then compares.
+func compareProtoAndMetric(wantText string, got *dto.Metric) error {
+	want := &dto.Metric{}
+	err := prototext.Unmarshal([]byte(wantText), want)
+	if err != nil {
+		return fmt.Errorf("unexpected error unmarshaling Metric text %v", wantText)
+	}
+	wantProto, err := proto.Marshal(want)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling Metric %v", want)
+	}
+
+	gotProto, err := proto.Marshal(got)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling Metric %v", got)
+	}
+
+	if bytes.Compare(wantProto, gotProto) != 0 {
+		return fmt.Errorf("Wanted Metric %v, got %v.", want, got)
+	}
+	return nil
+}

prometheus/testutil/testutil.go

@@ -45,11 +45,12 @@ import (
 	"reflect"
 
 	"github.com/davecgh/go-spew/spew"
-	dto "github.com/prometheus/client_model/go"
-	"github.com/prometheus/common/expfmt"
-
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/internal"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"
+	"google.golang.org/protobuf/encoding/prototext"
+	"google.golang.org/protobuf/proto"
 )
 
 // ToFloat64 collects all Metrics from the provided Collector. It expects that
@@ -341,3 +342,63 @@ func filterMetrics(metrics []*dto.MetricFamily, names []string) []*dto.MetricFam
 	}
 	return filtered
 }
+
+// CompareProtoAndMetric compares a text proto to a MetricFamily.
+//
+// It jumps through a few hoops because the current protobuf
+// implementation is deliberately creating an unstable formatting for the text
+// representation. So this takes the text representation of the expected
+// MetricFamily and unmarshals it into a proto message object first. Then it
+// marshals both the expected and the got proto message into a binary protobuf,
+// which it then compares.
+func CompareProtoAndMetric(wantText string, got *dto.Metric) error {
+	want := &dto.Metric{}
+	err := prototext.Unmarshal([]byte(wantText), want)
+	if err != nil {
+		return fmt.Errorf("unexpected error unmarshaling Metric text %v", wantText)
+	}
+	wantProto, err := proto.Marshal(want)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling Metric %v", want)
+	}
+
+	gotProto, err := proto.Marshal(got)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling Metric %v", got)
+	}
+
+	if bytes.Compare(wantProto, gotProto) != 0 {
+		return fmt.Errorf("Wanted Metric %v, got %v.", want, got)
+	}
+	return nil
+}
+
+// CompareProtoAndMetricFamily compares a text proto to a MetricFamily.
+//
+// It jumps through a few hoops because the current protobuf
+// implementation is deliberately creating an unstable formatting for the text
+// representation. So this takes the text representation of the expected
+// MetricFamily and unmarshals it into a proto message object first. Then it
+// marshals both the expected and the got proto message into a binary protobuf,
+// which it then compares.
+func CompareProtoAndMetricFamily(wantText string, got *dto.MetricFamily) error {
+	want := &dto.MetricFamily{}
+	err := prototext.Unmarshal([]byte(wantText), want)
+	if err != nil {
+		return fmt.Errorf("unexpected error unmarshaling MetricFamily text %v", wantText)
+	}
+	wantProto, err := proto.Marshal(want)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling MetricFamily %v", want)
+	}
+
+	gotProto, err := proto.Marshal(got)
+	if err != nil {
+		return fmt.Errorf("unexpected error marshaling MetricFamily %v", got)
+	}
+
+	if bytes.Compare(wantProto, gotProto) != 0 {
+		return fmt.Errorf("Wanted MetricFamily %v, got %v.", want, got)
+	}
+	return nil
+}