client_test.go

// Copyright The OpenTelemetry 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 otlpmetricgrpc_test

import (
	"context"
	"fmt"
	"net"
	"strings"
	"testing"
	"time"

	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/internal/otlpmetrictest"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
	"go.opentelemetry.io/otel/sdk/resource"

	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/durationpb"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"google.golang.org/grpc"
	"google.golang.org/grpc/encoding/gzip"
)

var (
	oneRecord = otlpmetrictest.OneRecordReader()

	testResource = resource.Empty()
)

func TestNewExporter_endToEnd(t *testing.T) {
	tests := []struct {
		name           string
		additionalOpts []otlpmetricgrpc.Option
	}{
		{
			name: "StandardExporter",
		},
		{
			name: "WithCompressor",
			additionalOpts: []otlpmetricgrpc.Option{
				otlpmetricgrpc.WithCompressor(gzip.Name),
			},
		},
		{
			name: "WithServiceConfig",
			additionalOpts: []otlpmetricgrpc.Option{
				otlpmetricgrpc.WithServiceConfig("{}"),
			},
		},
		{
			name: "WithDialOptions",
			additionalOpts: []otlpmetricgrpc.Option{
				otlpmetricgrpc.WithDialOption(grpc.WithBlock()),
			},
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			newExporterEndToEndTest(t, test.additionalOpts)
		})
	}
}

func newGRPCExporter(t *testing.T, ctx context.Context, endpoint string, additionalOpts ...otlpmetricgrpc.Option) *otlpmetric.Exporter {
	opts := []otlpmetricgrpc.Option{
		otlpmetricgrpc.WithInsecure(),
		otlpmetricgrpc.WithEndpoint(endpoint),
		otlpmetricgrpc.WithReconnectionPeriod(50 * time.Millisecond),
	}

	opts = append(opts, additionalOpts...)
	client := otlpmetricgrpc.NewClient(opts...)
	exp, err := otlpmetric.New(ctx, client)
	if err != nil {
		t.Fatalf("failed to create a new collector exporter: %v", err)
	}
	return exp
}

func newExporterEndToEndTest(t *testing.T, additionalOpts []otlpmetricgrpc.Option) {
	mc := runMockCollectorAtEndpoint(t, "localhost:56561")

	defer func() {
		_ = mc.stop()
	}()

	<-time.After(5 * time.Millisecond)

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint, additionalOpts...)
	defer func() {
		ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
		defer cancel()
		if err := exp.Shutdown(ctx); err != nil {
			panic(err)
		}
	}()

	otlpmetrictest.RunEndToEndTest(ctx, t, exp, mc)
}

func TestExporterShutdown(t *testing.T) {
	mc := runMockCollectorAtEndpoint(t, "localhost:56561")
	defer func() {
		_ = mc.Stop()
	}()

	<-time.After(5 * time.Millisecond)

	otlpmetrictest.RunExporterShutdownTest(t, func() otlpmetric.Client {
		return otlpmetricgrpc.NewClient(
			otlpmetricgrpc.WithInsecure(),
			otlpmetricgrpc.WithEndpoint(mc.endpoint),
			otlpmetricgrpc.WithReconnectionPeriod(50*time.Millisecond),
		)
	})
}

func TestNewExporter_invokeStartThenStopManyTimes(t *testing.T) {
	mc := runMockCollector(t)
	defer func() {
		_ = mc.stop()
	}()

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint)
	defer func() {
		if err := exp.Shutdown(ctx); err != nil {
			panic(err)
		}
	}()

	// Invoke Start numerous times, should return errAlreadyStarted
	for i := 0; i < 10; i++ {
		if err := exp.Start(ctx); err == nil || !strings.Contains(err.Error(), "already started") {
			t.Fatalf("#%d unexpected Start error: %v", i, err)
		}
	}

	if err := exp.Shutdown(ctx); err != nil {
		t.Fatalf("failed to Shutdown the exporter: %v", err)
	}
	// Invoke Shutdown numerous times
	for i := 0; i < 10; i++ {
		if err := exp.Shutdown(ctx); err != nil {
			t.Fatalf(`#%d got error (%v) expected none`, i, err)
		}
	}
}

func TestNewExporter_collectorConnectionDiesThenReconnectsWhenInRestMode(t *testing.T) {
	mc := runMockCollector(t)

	reconnectionPeriod := 20 * time.Millisecond
	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint,
		otlpmetricgrpc.WithRetry(otlpmetricgrpc.RetrySettings{Enabled: false}),
		otlpmetricgrpc.WithReconnectionPeriod(reconnectionPeriod))
	defer func() { require.NoError(t, exp.Shutdown(ctx)) }()

	// Wait for a connection.
	mc.ln.WaitForConn()

	// We'll now stop the collector right away to simulate a connection
	// dying in the midst of communication or even not existing before.
	require.NoError(t, mc.stop())

	// first export, it will send disconnected message to the channel on export failure,
	// trigger almost immediate reconnection
	require.Error(t, exp.Export(ctx, testResource, oneRecord))

	// second export, it will detect connection issue, change state of exporter to disconnected and
	// send message to disconnected channel but this time reconnection gouroutine will be in (rest mode, not listening to the disconnected channel)
	require.Error(t, exp.Export(ctx, testResource, oneRecord))

	// as a result we have exporter in disconnected state waiting for disconnection message to reconnect

	// resurrect collector
	nmc := runMockCollectorAtEndpoint(t, mc.endpoint)

	// make sure reconnection loop hits beginning and goes back to waiting mode
	// after hitting beginning of the loop it should reconnect
	nmc.ln.WaitForConn()

	n := 10
	for i := 0; i < n; i++ {
		// when disconnected exp.Export doesnt send disconnected messages again
		// it just quits and return last connection error
		require.NoError(t, exp.Export(ctx, testResource, oneRecord))
	}

	nmaMetrics := nmc.getMetrics()

	if g, w := len(nmaMetrics), n; g != w {
		t.Fatalf("Connected collector: metrics: got %d want %d", g, w)
	}

	dMetrics := mc.getMetrics()
	// Expecting 0 metrics to have been received by the original but now dead collector
	if g, w := len(dMetrics), 0; g != w {
		t.Fatalf("Disconnected collector: spans: got %d want %d", g, w)
	}

	require.NoError(t, nmc.Stop())
}

func TestExporterExportFailureAndRecoveryModes(t *testing.T) {
	tts := []struct {
		name   string
		errors []error
		rs     otlpmetricgrpc.RetrySettings
		fn     func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector)
		opts   []otlpmetricgrpc.Option
	}{
		{
			name: "Do not retry if succeeded",
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				require.NoError(t, exp.Export(ctx, testResource, oneRecord))

				metrics := mc.getMetrics()

				require.Len(t, metrics, 1)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 success request.")
			},
		},
		{
			name: "Do not retry if 'error' is ok",
			errors: []error{
				status.Error(codes.OK, ""),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				require.NoError(t, exp.Export(ctx, testResource, oneRecord))

				metrics := mc.getMetrics()

				require.Len(t, metrics, 0)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 error OK request.")
			},
		},
		{
			name: "Fail three times and succeed",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  300 * time.Millisecond,
				InitialInterval: 2 * time.Millisecond,
				MaxInterval:     10 * time.Millisecond,
			},
			errors: []error{
				status.Error(codes.Unavailable, "backend under pressure"),
				status.Error(codes.Unavailable, "backend under pressure"),
				status.Error(codes.Unavailable, "backend under pressure"),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				require.NoError(t, exp.Export(ctx, testResource, oneRecord))

				metrics := mc.getMetrics()

				require.Len(t, metrics, 1)
				require.Equal(t, 4, mc.metricSvc.requests, "metric service must receive 3 failure requests and 1 success request.")
			},
		},
		{
			name: "Permanent error should not be retried",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  300 * time.Millisecond,
				InitialInterval: 2 * time.Millisecond,
				MaxInterval:     10 * time.Millisecond,
			},
			errors: []error{
				status.Error(codes.InvalidArgument, "invalid arguments"),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				require.Error(t, exp.Export(ctx, testResource, oneRecord))

				metric := mc.getMetrics()

				require.Len(t, metric, 0)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 error requests.")
			},
		},
		{
			name: "Test all transient errors and succeed",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  500 * time.Millisecond,
				InitialInterval: 1 * time.Millisecond,
				MaxInterval:     2 * time.Millisecond,
			},
			errors: []error{
				status.Error(codes.Canceled, ""),
				status.Error(codes.DeadlineExceeded, ""),
				status.Error(codes.ResourceExhausted, ""),
				status.Error(codes.Aborted, ""),
				status.Error(codes.OutOfRange, ""),
				status.Error(codes.Unavailable, ""),
				status.Error(codes.DataLoss, ""),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				require.NoError(t, exp.Export(ctx, testResource, oneRecord))

				metrics := mc.getMetrics()

				require.Len(t, metrics, 1)
				require.Equal(t, 8, mc.metricSvc.requests, "metric service must receive 9 failure requests and 1 success request.")
			},
		},
		{
			name: "Retry should honor server throttling",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  time.Minute,
				InitialInterval: time.Nanosecond,
				MaxInterval:     time.Nanosecond,
			},
			opts: []otlpmetricgrpc.Option{
				otlpmetricgrpc.WithTimeout(time.Millisecond * 100),
			},
			errors: []error{
				newThrottlingError(codes.ResourceExhausted, time.Second*30),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				err := exp.Export(ctx, testResource, oneRecord)
				require.Error(t, err)
				require.Equal(t, "context deadline exceeded", err.Error())

				metrics := mc.getMetrics()

				require.Len(t, metrics, 0)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 failure requests and 1 success request.")
			},
		},
		{
			name: "Retry should fail if server throttling is higher than the MaxElapsedTime",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  time.Millisecond * 100,
				InitialInterval: time.Nanosecond,
				MaxInterval:     time.Nanosecond,
			},
			errors: []error{
				newThrottlingError(codes.ResourceExhausted, time.Minute),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				err := exp.Export(ctx, testResource, oneRecord)
				require.Error(t, err)
				require.Equal(t, "max elapsed time expired when respecting server throttle: rpc error: code = ResourceExhausted desc = ", err.Error())

				metrics := mc.getMetrics()

				require.Len(t, metrics, 0)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 failure requests and 1 success request.")
			},
		},
		{
			name: "Retry stops if takes too long",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled:         true,
				MaxElapsedTime:  time.Millisecond * 100,
				InitialInterval: time.Millisecond * 50,
				MaxInterval:     time.Millisecond * 50,
			},
			errors: []error{
				status.Error(codes.Unavailable, "unavailable"),
				status.Error(codes.Unavailable, "unavailable"),
				status.Error(codes.Unavailable, "unavailable"),
				status.Error(codes.Unavailable, "unavailable"),
				status.Error(codes.Unavailable, "unavailable"),
				status.Error(codes.Unavailable, "unavailable"),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				err := exp.Export(ctx, testResource, oneRecord)
				require.Error(t, err)

				require.Equal(t, "max elapsed time expired: rpc error: code = Unavailable desc = unavailable", err.Error())

				metrics := mc.getMetrics()

				require.Len(t, metrics, 0)
				require.LessOrEqual(t, 1, mc.metricSvc.requests, "metric service must receive at least 1 failure requests.")
			},
		},
		{
			name: "Disabled retry",
			rs: otlpmetricgrpc.RetrySettings{
				Enabled: false,
			},
			errors: []error{
				status.Error(codes.Unavailable, "unavailable"),
			},
			fn: func(t *testing.T, ctx context.Context, exp *otlpmetric.Exporter, mc *mockCollector) {
				err := exp.Export(ctx, testResource, oneRecord)
				require.Error(t, err)

				require.Equal(t, "rpc error: code = Unavailable desc = unavailable", err.Error())

				metrics := mc.getMetrics()

				require.Len(t, metrics, 0)
				require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 failure requests.")
			},
		},
	}

	for _, tt := range tts {
		t.Run(tt.name, func(t *testing.T) {
			ctx := context.Background()

			mc := runMockCollectorWithConfig(t, &mockConfig{
				errors: tt.errors,
			})

			opts := []otlpmetricgrpc.Option{
				otlpmetricgrpc.WithRetry(tt.rs),
			}

			if len(tt.opts) != 0 {
				opts = append(opts, tt.opts...)
			}

			exp := newGRPCExporter(t, ctx, mc.endpoint, opts...)

			tt.fn(t, ctx, exp, mc)

			require.NoError(t, mc.Stop())
			require.NoError(t, exp.Shutdown(ctx))
		})
	}

}

func TestPermanentErrorsShouldNotBeRetried(t *testing.T) {
	permanentErrors := []*status.Status{
		status.New(codes.Unknown, "Unknown"),
		status.New(codes.InvalidArgument, "InvalidArgument"),
		status.New(codes.NotFound, "NotFound"),
		status.New(codes.AlreadyExists, "AlreadyExists"),
		status.New(codes.FailedPrecondition, "FailedPrecondition"),
		status.New(codes.Unimplemented, "Unimplemented"),
		status.New(codes.Internal, "Internal"),
		status.New(codes.PermissionDenied, ""),
		status.New(codes.Unauthenticated, ""),
	}

	for _, sts := range permanentErrors {
		t.Run(sts.Code().String(), func(t *testing.T) {
			ctx := context.Background()

			mc := runMockCollectorWithConfig(t, &mockConfig{
				errors: []error{sts.Err()},
			})

			exp := newGRPCExporter(t, ctx, mc.endpoint)

			err := exp.Export(ctx, testResource, oneRecord)
			require.Error(t, err)
			require.Len(t, mc.getMetrics(), 0)
			require.Equal(t, 1, mc.metricSvc.requests, "metric service must receive 1 permanent error requests.")

			require.NoError(t, mc.Stop())
			require.NoError(t, exp.Shutdown(ctx))
		})
	}
}

func newThrottlingError(code codes.Code, duration time.Duration) error {
	s := status.New(code, "")

	s, _ = s.WithDetails(&errdetails.RetryInfo{RetryDelay: durationpb.New(duration)})

	return s.Err()
}

func TestNewExporter_collectorConnectionDiesThenReconnects(t *testing.T) {
	mc := runMockCollector(t)

	reconnectionPeriod := 50 * time.Millisecond
	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint,
		otlpmetricgrpc.WithRetry(otlpmetricgrpc.RetrySettings{Enabled: false}),
		otlpmetricgrpc.WithReconnectionPeriod(reconnectionPeriod))
	defer func() { require.NoError(t, exp.Shutdown(ctx)) }()

	mc.ln.WaitForConn()

	// We'll now stop the collector right away to simulate a connection
	// dying in the midst of communication or even not existing before.
	require.NoError(t, mc.stop())

	// In the test below, we'll stop the collector many times,
	// while exporting metrics and test to ensure that we can
	// reconnect.
	for j := 0; j < 3; j++ {

		// No endpoint up.
		require.Error(t, exp.Export(ctx, testResource, oneRecord))

		// Now resurrect the collector by making a new one but reusing the
		// old endpoint, and the collector should reconnect automatically.
		nmc := runMockCollectorAtEndpoint(t, mc.endpoint)

		// Give the exporter sometime to reconnect
		nmc.ln.WaitForConn()

		n := 10
		for i := 0; i < n; i++ {
			require.NoError(t, exp.Export(ctx, testResource, oneRecord))
		}

		nmaMetrics := nmc.getMetrics()
		// Expecting 10 metrics that were sampled, given that
		if g, w := len(nmaMetrics), n; g != w {
			t.Fatalf("Round #%d: Connected collector: spans: got %d want %d", j, g, w)
		}

		dMetrics := mc.getMetrics()
		// Expecting 0 metrics to have been received by the original but now dead collector
		if g, w := len(dMetrics), 0; g != w {
			t.Fatalf("Round #%d: Disconnected collector: spans: got %d want %d", j, g, w)
		}

		// Disconnect for the next try.
		require.NoError(t, nmc.stop())
	}
}

// This test takes a long time to run: to skip it, run tests using: -short
func TestNewExporter_collectorOnBadConnection(t *testing.T) {
	if testing.Short() {
		t.Skipf("Skipping this long running test")
	}

	ln, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		t.Fatalf("Failed to grab an available port: %v", err)
	}
	// Firstly close the "collector's" channel: optimistically this endpoint won't get reused ASAP
	// However, our goal of closing it is to simulate an unavailable connection
	_ = ln.Close()

	_, collectorPortStr, _ := net.SplitHostPort(ln.Addr().String())

	endpoint := fmt.Sprintf("localhost:%s", collectorPortStr)
	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, endpoint)
	_ = exp.Shutdown(ctx)
}

func TestNewExporter_withEndpoint(t *testing.T) {
	mc := runMockCollector(t)
	defer func() {
		_ = mc.stop()
	}()

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint)
	_ = exp.Shutdown(ctx)
}

func TestNewExporter_withHeaders(t *testing.T) {
	mc := runMockCollector(t)
	defer func() {
		_ = mc.stop()
	}()

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint,
		otlpmetricgrpc.WithHeaders(map[string]string{"header1": "value1"}))
	require.NoError(t, exp.Export(ctx, testResource, oneRecord))

	defer func() {
		_ = exp.Shutdown(ctx)
	}()

	headers := mc.getHeaders()
	require.Len(t, headers.Get("header1"), 1)
	assert.Equal(t, "value1", headers.Get("header1")[0])
}

func TestNewExporter_WithTimeout(t *testing.T) {
	tts := []struct {
		name    string
		fn      func(exp *otlpmetric.Exporter) error
		timeout time.Duration
		metrics int
		spans   int
		code    codes.Code
		delay   bool
	}{
		{
			name: "Timeout Metrics",
			fn: func(exp *otlpmetric.Exporter) error {
				return exp.Export(context.Background(), testResource, oneRecord)
			},
			timeout: time.Millisecond * 100,
			code:    codes.DeadlineExceeded,
			delay:   true,
		},

		{
			name: "No Timeout Metrics",
			fn: func(exp *otlpmetric.Exporter) error {
				return exp.Export(context.Background(), testResource, oneRecord)
			},
			timeout: time.Minute,
			metrics: 1,
			code:    codes.OK,
		},
	}

	for _, tt := range tts {
		t.Run(tt.name, func(t *testing.T) {

			mc := runMockCollector(t)
			if tt.delay {
				mc.metricSvc.delay = time.Second * 10
			}
			defer func() {
				_ = mc.stop()
			}()

			ctx := context.Background()
			exp := newGRPCExporter(t, ctx, mc.endpoint, otlpmetricgrpc.WithTimeout(tt.timeout), otlpmetricgrpc.WithRetry(otlpmetricgrpc.RetrySettings{Enabled: false}))
			defer func() {
				_ = exp.Shutdown(ctx)
			}()

			err := tt.fn(exp)

			if tt.code == codes.OK {
				require.NoError(t, err)
			} else {
				require.Error(t, err)
			}

			s := status.Convert(err)
			require.Equal(t, tt.code, s.Code())

			require.Len(t, mc.getMetrics(), tt.metrics)
		})
	}
}

func TestNewExporter_withInvalidSecurityConfiguration(t *testing.T) {
	mc := runMockCollector(t)
	defer func() {
		_ = mc.stop()
	}()

	ctx := context.Background()
	client := otlpmetricgrpc.NewClient(otlpmetricgrpc.WithEndpoint(mc.endpoint))
	exp, err := otlpmetric.New(ctx, client)
	if err != nil {
		t.Fatalf("failed to create a new collector exporter: %v", err)
	}

	err = exp.Export(ctx, testResource, oneRecord)

	expectedErr := fmt.Sprintf("metrics exporter is disconnected from the server %s: grpc: no transport security set (use grpc.WithInsecure() explicitly or set credentials)", mc.endpoint)

	require.Error(t, err)
	require.Equal(t, expectedErr, err.Error())

	defer func() {
		_ = exp.Shutdown(ctx)
	}()
}

func TestDisconnected(t *testing.T) {
	ctx := context.Background()
	// The endpoint is whatever, we want to be disconnected. But we
	// setting a blocking connection, so dialing to the invalid
	// endpoint actually fails.
	exp := newGRPCExporter(t, ctx, "invalid",
		otlpmetricgrpc.WithReconnectionPeriod(time.Hour),
		otlpmetricgrpc.WithDialOption(
			grpc.WithBlock(),
			grpc.FailOnNonTempDialError(true),
		),
	)
	defer func() {
		assert.NoError(t, exp.Shutdown(ctx))
	}()

	assert.Error(t, exp.Export(ctx, testResource, oneRecord))
}

func TestEmptyData(t *testing.T) {
	mc := runMockCollectorAtEndpoint(t, "localhost:56561")

	defer func() {
		_ = mc.stop()
	}()

	<-time.After(5 * time.Millisecond)

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint)
	defer func() {
		assert.NoError(t, exp.Shutdown(ctx))
	}()

	assert.NoError(t, exp.Export(ctx, testResource, otlpmetrictest.EmptyReader()))
}

func TestFailedMetricTransform(t *testing.T) {
	mc := runMockCollectorAtEndpoint(t, "localhost:56561")

	defer func() {
		_ = mc.stop()
	}()

	<-time.After(5 * time.Millisecond)

	ctx := context.Background()
	exp := newGRPCExporter(t, ctx, mc.endpoint)
	defer func() {
		assert.NoError(t, exp.Shutdown(ctx))
	}()

	assert.Error(t, exp.Export(ctx, testResource, otlpmetrictest.FailReader{}))
}