diff --git a/discovery/consul/consul_test.go b/discovery/consul/consul_test.go
index 040040ae9..ee55abdc9 100644
--- a/discovery/consul/consul_test.go
+++ b/discovery/consul/consul_test.go
@@ -56,15 +56,12 @@ func TestConfiguredService(t *testing.T) {
 	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
 
 	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
-	if err != nil {
-		t.Errorf("Unexpected error when initializing discovery %v", err)
-	}
-	if !consulDiscovery.shouldWatch("configuredServiceName", []string{""}) {
-		t.Errorf("Expected service %s to be watched", "configuredServiceName")
-	}
-	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
-		t.Errorf("Expected service %s to not be watched", "nonConfiguredServiceName")
-	}
+	require.NoError(t, err, "when initializing discovery")
+	require.True(t, consulDiscovery.shouldWatch("configuredServiceName", []string{""}),
+		"Expected service %s to be watched", "configuredServiceName")
+	require.False(t, consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}),
+		"Expected service %s to not be watched", "nonConfiguredServiceName")
+
 }
 
 func TestConfiguredServiceWithTag(t *testing.T) {
@@ -76,21 +73,18 @@ func TestConfiguredServiceWithTag(t *testing.T) {
 	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
 
 	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
-	if err != nil {
-		t.Errorf("Unexpected error when initializing discovery %v", err)
-	}
-	if consulDiscovery.shouldWatch("configuredServiceName", []string{""}) {
-		t.Errorf("Expected service %s to not be watched without tag", "configuredServiceName")
-	}
-	if !consulDiscovery.shouldWatch("configuredServiceName", []string{"http"}) {
-		t.Errorf("Expected service %s to be watched with tag %s", "configuredServiceName", "http")
-	}
-	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
-		t.Errorf("Expected service %s to not be watched without tag", "nonConfiguredServiceName")
-	}
-	if consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{"http"}) {
-		t.Errorf("Expected service %s to not be watched with tag %s", "nonConfiguredServiceName", "http")
-	}
+	require.NoError(t, err, "when initializing discovery")
+	require.False(t, consulDiscovery.shouldWatch("configuredServiceName", []string{""}),
+		"Expected service %s to not be watched without tag", "configuredServiceName")
+
+	require.True(t, consulDiscovery.shouldWatch("configuredServiceName", []string{"http"}),
+		"Expected service %s to be watched with tag %s", "configuredServiceName", "http")
+
+	require.False(t, consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}),
+		"Expected service %s to not be watched without tag", "nonConfiguredServiceName")
+
+	require.False(t, consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{"http"}),
+		"Expected service %s to not be watched with tag %s", "nonConfiguredServiceName", "http")
 }
 
 func TestConfiguredServiceWithTags(t *testing.T) {
@@ -173,13 +167,10 @@ func TestConfiguredServiceWithTags(t *testing.T) {
 		metrics := NewTestMetrics(t, tc.conf, prometheus.NewRegistry())
 
 		consulDiscovery, err := NewDiscovery(tc.conf, nil, metrics)
-		if err != nil {
-			t.Errorf("Unexpected error when initializing discovery %v", err)
-		}
+		require.NoError(t, err, "when initializing discovery")
 		ret := consulDiscovery.shouldWatch(tc.serviceName, tc.serviceTags)
-		if ret != tc.shouldWatch {
-			t.Errorf("Expected should watch? %t, got %t. Watched service and tags: %s %+v, input was %s %+v", tc.shouldWatch, ret, tc.conf.Services, tc.conf.ServiceTags, tc.serviceName, tc.serviceTags)
-		}
+		require.Equal(t, tc.shouldWatch, ret, "Watched service and tags: %s %+v, input was %s %+v",
+			tc.conf.Services, tc.conf.ServiceTags, tc.serviceName, tc.serviceTags)
 	}
 }
 
@@ -189,12 +180,8 @@ func TestNonConfiguredService(t *testing.T) {
 	metrics := NewTestMetrics(t, conf, prometheus.NewRegistry())
 
 	consulDiscovery, err := NewDiscovery(conf, nil, metrics)
-	if err != nil {
-		t.Errorf("Unexpected error when initializing discovery %v", err)
-	}
-	if !consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}) {
-		t.Errorf("Expected service %s to be watched", "nonConfiguredServiceName")
-	}
+	require.NoError(t, err, "when initializing discovery")
+	require.True(t, consulDiscovery.shouldWatch("nonConfiguredServiceName", []string{""}), "Expected service %s to be watched", "nonConfiguredServiceName")
 }
 
 const (
@@ -267,7 +254,7 @@ func newServer(t *testing.T) (*httptest.Server, *SDConfig) {
 			time.Sleep(5 * time.Second)
 			response = ServicesTestAnswer
 		default:
-			t.Errorf("Unhandled consul call: %s", r.URL)
+			require.FailNow(t, "Unhandled consul call: %s", r.URL)
 		}
 		w.Header().Add("X-Consul-Index", "1")
 		w.Write([]byte(response))
@@ -502,13 +489,10 @@ oauth2:
 			var config SDConfig
 			err := config.UnmarshalYAML(unmarshal([]byte(test.config)))
 			if err != nil {
-				require.Equalf(t, err.Error(), test.errMessage, "Expected error '%s', got '%v'", test.errMessage, err)
-				return
-			}
-			if test.errMessage != "" {
-				t.Errorf("Expected error %s, got none", test.errMessage)
+				require.EqualError(t, err, test.errMessage)
 				return
 			}
+			require.Empty(t, test.errMessage, "Expected error.")
 
 			require.Equal(t, test.expected, config)
 		})
diff --git a/discovery/file/file_test.go b/discovery/file/file_test.go
index 8a5057089..b473c2ce6 100644
--- a/discovery/file/file_test.go
+++ b/discovery/file/file_test.go
@@ -358,9 +358,7 @@ func TestInvalidFile(t *testing.T) {
 
 			// Verify that we've received nothing.
 			time.Sleep(defaultWait)
-			if runner.lastReceive().After(now) {
-				t.Fatalf("unexpected targets received: %v", runner.targets())
-			}
+			require.False(t, runner.lastReceive().After(now), "Unexpected targets received.")
 		})
 	}
 }
diff --git a/discovery/kubernetes/kubernetes_test.go b/discovery/kubernetes/kubernetes_test.go
index 4071ebc34..f1f8070e8 100644
--- a/discovery/kubernetes/kubernetes_test.go
+++ b/discovery/kubernetes/kubernetes_test.go
@@ -131,14 +131,8 @@ func (d k8sDiscoveryTest) Run(t *testing.T) {
 	go readResultWithTimeout(t, ch, d.expectedMaxItems, time.Second, resChan)
 
 	dd, ok := d.discovery.(hasSynced)
-	if !ok {
-		t.Errorf("discoverer does not implement hasSynced interface")
-		return
-	}
-	if !cache.WaitForCacheSync(ctx.Done(), dd.hasSynced) {
-		t.Errorf("discoverer failed to sync: %v", dd)
-		return
-	}
+	require.True(t, ok, "discoverer does not implement hasSynced interface")
+	require.True(t, cache.WaitForCacheSync(ctx.Done(), dd.hasSynced), "discoverer failed to sync: %v", dd)
 
 	if d.afterStart != nil {
 		d.afterStart()
diff --git a/discovery/manager_test.go b/discovery/manager_test.go
index 2f6e03aa5..52159d94f 100644
--- a/discovery/manager_test.go
+++ b/discovery/manager_test.go
@@ -694,7 +694,7 @@ func TestTargetUpdatesOrder(t *testing.T) {
 			for x := 0; x < totalUpdatesCount; x++ {
 				select {
 				case <-ctx.Done():
-					t.Fatalf("%d: no update arrived within the timeout limit", x)
+					require.FailNow(t, "%d: no update arrived within the timeout limit", x)
 				case tgs := <-provUpdates:
 					discoveryManager.updateGroup(poolKey{setName: strconv.Itoa(i), provider: tc.title}, tgs)
 					for _, got := range discoveryManager.allGroups() {
@@ -756,10 +756,8 @@ func verifySyncedPresence(t *testing.T, tGroups map[string][]*targetgroup.Group,
 
 func verifyPresence(t *testing.T, tSets map[poolKey]map[string]*targetgroup.Group, poolKey poolKey, label string, present bool) {
 	t.Helper()
-	if _, ok := tSets[poolKey]; !ok {
-		t.Fatalf("'%s' should be present in Pool keys: %v", poolKey, tSets)
-		return
-	}
+	_, ok := tSets[poolKey]
+	require.True(t, ok, "'%s' should be present in Pool keys: %v", poolKey, tSets)
 
 	match := false
 	var mergedTargets string
@@ -776,7 +774,7 @@ func verifyPresence(t *testing.T, tSets map[poolKey]map[string]*targetgroup.Grou
 		if !present {
 			msg = "not"
 		}
-		t.Fatalf("%q should %s be present in Targets labels: %q", label, msg, mergedTargets)
+		require.FailNow(t, "%q should %s be present in Targets labels: %q", label, msg, mergedTargets)
 	}
 }
 
@@ -1088,22 +1086,14 @@ func TestTargetSetRecreatesEmptyStaticConfigs(t *testing.T) {
 	syncedTargets = <-discoveryManager.SyncCh()
 	p = pk("static", "prometheus", 1)
 	targetGroups, ok := discoveryManager.targets[p]
-	if !ok {
-		t.Fatalf("'%v' should be present in target groups", p)
-	}
+	require.True(t, ok, "'%v' should be present in target groups", p)
 	group, ok := targetGroups[""]
-	if !ok {
-		t.Fatalf("missing '' key in target groups %v", targetGroups)
-	}
+	require.True(t, ok, "missing '' key in target groups %v", targetGroups)
 
-	if len(group.Targets) != 0 {
-		t.Fatalf("Invalid number of targets: expected 0, got %d", len(group.Targets))
-	}
+	require.Empty(t, group.Targets, "Invalid number of targets.")
 	require.Len(t, syncedTargets, 1)
 	require.Len(t, syncedTargets["prometheus"], 1)
-	if lbls := syncedTargets["prometheus"][0].Labels; lbls != nil {
-		t.Fatalf("Unexpected Group: expected nil Labels, got %v", lbls)
-	}
+	require.Nil(t, syncedTargets["prometheus"][0].Labels)
 }
 
 func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
@@ -1131,9 +1121,7 @@ func TestIdenticalConfigurationsAreCoalesced(t *testing.T) {
 	syncedTargets := <-discoveryManager.SyncCh()
 	verifyPresence(t, discoveryManager.targets, pk("static", "prometheus", 0), "{__address__=\"foo:9090\"}", true)
 	verifyPresence(t, discoveryManager.targets, pk("static", "prometheus2", 0), "{__address__=\"foo:9090\"}", true)
-	if len(discoveryManager.providers) != 1 {
-		t.Fatalf("Invalid number of providers: expected 1, got %d", len(discoveryManager.providers))
-	}
+	require.Len(t, discoveryManager.providers, 1, "Invalid number of providers.")
 	require.Len(t, syncedTargets, 2)
 	verifySyncedPresence(t, syncedTargets, "prometheus", "{__address__=\"foo:9090\"}", true)
 	require.Len(t, syncedTargets["prometheus"], 1)
@@ -1231,9 +1219,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	<-discoveryManager.SyncCh()
 
 	failedCount := client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
-	if failedCount != 3 {
-		t.Fatalf("Expected to have 3 failed configs, got: %v", failedCount)
-	}
+	require.Equal(t, 3.0, failedCount, "Expected to have 3 failed configs.")
 
 	c["prometheus"] = Configs{
 		staticConfig("foo:9090"),
@@ -1242,9 +1228,7 @@ func TestGaugeFailedConfigs(t *testing.T) {
 	<-discoveryManager.SyncCh()
 
 	failedCount = client_testutil.ToFloat64(discoveryManager.metrics.FailedConfigs)
-	if failedCount != 0 {
-		t.Fatalf("Expected to get no failed config, got: %v", failedCount)
-	}
+	require.Equal(t, 0.0, failedCount, "Expected to get no failed config.")
 }
 
 func TestCoordinationWithReceiver(t *testing.T) {
@@ -1388,19 +1372,14 @@ func TestCoordinationWithReceiver(t *testing.T) {
 				time.Sleep(expected.delay)
 				select {
 				case <-ctx.Done():
-					t.Fatalf("step %d: no update received in the expected timeframe", i)
+					require.FailNow(t, "step %d: no update received in the expected timeframe", i)
 				case tgs, ok := <-mgr.SyncCh():
-					if !ok {
-						t.Fatalf("step %d: discovery manager channel is closed", i)
-					}
-					if len(tgs) != len(expected.tgs) {
-						t.Fatalf("step %d: target groups mismatch, got: %d, expected: %d\ngot: %#v\nexpected: %#v",
-							i, len(tgs), len(expected.tgs), tgs, expected.tgs)
-					}
+					require.True(t, ok, "step %d: discovery manager channel is closed", i)
+					require.Equal(t, len(expected.tgs), len(tgs), "step %d: targets mismatch", i)
+
 					for k := range expected.tgs {
-						if _, ok := tgs[k]; !ok {
-							t.Fatalf("step %d: target group not found: %s\ngot: %#v", i, k, tgs)
-						}
+						_, ok := tgs[k]
+						require.True(t, ok, "step %d: target group not found: %s", i, k)
 						assertEqualGroups(t, tgs[k], expected.tgs[k])
 					}
 				}
diff --git a/discovery/marathon/marathon_test.go b/discovery/marathon/marathon_test.go
index c78cc1e3c..d177ae49f 100644
--- a/discovery/marathon/marathon_test.go
+++ b/discovery/marathon/marathon_test.go
@@ -69,23 +69,15 @@ func TestMarathonSDHandleError(t *testing.T) {
 		}
 	)
 	tgs, err := testUpdateServices(client)
-	if !errors.Is(err, errTesting) {
-		t.Fatalf("Expected error: %s", err)
-	}
-	if len(tgs) != 0 {
-		t.Fatalf("Got group: %s", tgs)
-	}
+	require.ErrorIs(t, err, errTesting)
+	require.Empty(t, tgs, "Expected no target groups.")
 }
 
 func TestMarathonSDEmptyList(t *testing.T) {
 	client := func(_ context.Context, _ *http.Client, _ string) (*appList, error) { return &appList{}, nil }
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) > 0 {
-		t.Fatalf("Got group: %v", tgs)
-	}
+	require.NoError(t, err)
+	require.Empty(t, tgs, "Expected no target groups.")
 }
 
 func marathonTestAppList(labels map[string]string, runningTasks int) *appList {
@@ -119,28 +111,16 @@ func TestMarathonSDSendGroup(t *testing.T) {
 		return marathonTestAppList(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
 
 	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 1, len(tg.Targets), "Expected 1 target.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 1 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:31000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:31000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
 }
 
 func TestMarathonSDRemoveApp(t *testing.T) {
@@ -153,40 +133,27 @@ func TestMarathonSDRemoveApp(t *testing.T) {
 	defer refreshMetrics.Unregister()
 
 	md, err := NewDiscovery(cfg, nil, metrics)
-	if err != nil {
-		t.Fatalf("%s", err)
-	}
+	require.NoError(t, err)
 
 	md.appsClient = func(_ context.Context, _ *http.Client, _ string) (*appList, error) {
 		return marathonTestAppList(marathonValidLabel, 1), nil
 	}
 	tgs, err := md.refresh(context.Background())
-	if err != nil {
-		t.Fatalf("Got error on first update: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 targetgroup, got", len(tgs))
-	}
+	require.NoError(t, err, "Got error on first update.")
+	require.Equal(t, 1, len(tgs), "Expected 1 targetgroup.")
 	tg1 := tgs[0]
 
 	md.appsClient = func(_ context.Context, _ *http.Client, _ string) (*appList, error) {
 		return marathonTestAppList(marathonValidLabel, 0), nil
 	}
 	tgs, err = md.refresh(context.Background())
-	if err != nil {
-		t.Fatalf("Got error on second update: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 targetgroup, got", len(tgs))
-	}
+	require.NoError(t, err, "Got error on second update.")
+	require.Equal(t, 1, len(tgs), "Expected 1 targetgroup.")
+
 	tg2 := tgs[0]
 
-	if tg2.Source != tg1.Source {
-		if len(tg2.Targets) > 0 {
-			t.Errorf("Got a non-empty target set: %s", tg2.Targets)
-		}
-		t.Fatalf("Source is different: %s != %s", tg1.Source, tg2.Source)
-	}
+	require.Equal(t, tg1.Source, tg2.Source, "Source is different.")
+	require.NotEmpty(t, tg2.Targets, "Got a non-empty target set.")
 }
 
 func marathonTestAppListWithMultiplePorts(labels map[string]string, runningTasks int) *appList {
@@ -221,34 +188,22 @@ func TestMarathonSDSendGroupWithMultiplePort(t *testing.T) {
 		return marathonTestAppListWithMultiplePorts(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:31000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:31000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]),
+		"Wrong portMappings label from the first port: %s", tgt[model.AddressLabel])
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:32000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:32000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]),
+		"Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
 }
 
 func marathonTestZeroTaskPortAppList(labels map[string]string, runningTasks int) *appList {
@@ -278,20 +233,12 @@ func TestMarathonZeroTaskPorts(t *testing.T) {
 		return marathonTestZeroTaskPortAppList(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
 
-	if tg.Source != "test-service-zero-ports" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 0 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
+	tg := tgs[0]
+	require.Equal(t, "test-service-zero-ports", tg.Source, "Wrong target group name.")
+	require.Empty(t, tg.Targets, "Wrong number of targets.")
 }
 
 func Test500ErrorHttpResponseWithValidJSONBody(t *testing.T) {
@@ -306,9 +253,7 @@ func Test500ErrorHttpResponseWithValidJSONBody(t *testing.T) {
 	defer ts.Close()
 	// Execute test case and validate behavior.
 	_, err := testUpdateServices(nil)
-	if err == nil {
-		t.Fatalf("Expected error for 5xx HTTP response from marathon server, got nil")
-	}
+	require.Error(t, err, "Expected error for 5xx HTTP response from marathon server.")
 }
 
 func marathonTestAppListWithPortDefinitions(labels map[string]string, runningTasks int) *appList {
@@ -346,40 +291,24 @@ func TestMarathonSDSendGroupWithPortDefinitions(t *testing.T) {
 		return marathonTestAppListWithPortDefinitions(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:1234" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:1234", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]),
+		"Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]),
+		"Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:5678" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:5678", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
 
 func marathonTestAppListWithPortDefinitionsRequirePorts(labels map[string]string, runningTasks int) *appList {
@@ -416,40 +345,22 @@ func TestMarathonSDSendGroupWithPortDefinitionsRequirePorts(t *testing.T) {
 		return marathonTestAppListWithPortDefinitionsRequirePorts(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:31000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:31000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:32000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:32000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
 
 func marathonTestAppListWithPorts(labels map[string]string, runningTasks int) *appList {
@@ -481,40 +392,22 @@ func TestMarathonSDSendGroupWithPorts(t *testing.T) {
 		return marathonTestAppListWithPorts(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:31000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:31000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:32000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:32000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
 
 func marathonTestAppListWithContainerPortMappings(labels map[string]string, runningTasks int) *appList {
@@ -555,40 +448,22 @@ func TestMarathonSDSendGroupWithContainerPortMappings(t *testing.T) {
 		return marathonTestAppListWithContainerPortMappings(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:12345" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:12345", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:32000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:32000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
 
 func marathonTestAppListWithDockerContainerPortMappings(labels map[string]string, runningTasks int) *appList {
@@ -629,40 +504,22 @@ func TestMarathonSDSendGroupWithDockerContainerPortMappings(t *testing.T) {
 		return marathonTestAppListWithDockerContainerPortMappings(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "mesos-slave1:31000" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:31000", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "mesos-slave1:12345" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "mesos-slave1:12345", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
 
 func marathonTestAppListWithContainerNetworkAndPortMappings(labels map[string]string, runningTasks int) *appList {
@@ -707,38 +564,20 @@ func TestMarathonSDSendGroupWithContainerNetworkAndPortMapping(t *testing.T) {
 		return marathonTestAppListWithContainerNetworkAndPortMappings(marathonValidLabel, 1), nil
 	}
 	tgs, err := testUpdateServices(client)
-	if err != nil {
-		t.Fatalf("Got error: %s", err)
-	}
-	if len(tgs) != 1 {
-		t.Fatal("Expected 1 target group, got", len(tgs))
-	}
-	tg := tgs[0]
+	require.NoError(t, err)
+	require.Equal(t, 1, len(tgs), "Expected 1 target group.")
+
+	tg := tgs[0]
+	require.Equal(t, "test-service", tg.Source, "Wrong target group name.")
+	require.Equal(t, 2, len(tg.Targets), "Wrong number of targets.")
 
-	if tg.Source != "test-service" {
-		t.Fatalf("Wrong target group name: %s", tg.Source)
-	}
-	if len(tg.Targets) != 2 {
-		t.Fatalf("Wrong number of targets: %v", tg.Targets)
-	}
 	tgt := tg.Targets[0]
-	if tgt[model.AddressLabel] != "1.2.3.4:8080" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "yes" {
-		t.Fatalf("Wrong first portMappings label from the first port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong first portDefinitions label from the first port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "1.2.3.4:8080", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "yes", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the first port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the first port.")
+
 	tgt = tg.Targets[1]
-	if tgt[model.AddressLabel] != "1.2.3.4:1234" {
-		t.Fatalf("Wrong target address: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portMappingLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portMappings label from the second port: %s", tgt[model.AddressLabel])
-	}
-	if tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")] != "" {
-		t.Fatalf("Wrong portDefinitions label from the second port: %s", tgt[model.AddressLabel])
-	}
+	require.Equal(t, "1.2.3.4:1234", string(tgt[model.AddressLabel]), "Wrong target address.")
+	require.Equal(t, "", string(tgt[model.LabelName(portMappingLabelPrefix+"prometheus")]), "Wrong portMappings label from the second port.")
+	require.Equal(t, "", string(tgt[model.LabelName(portDefinitionLabelPrefix+"prometheus")]), "Wrong portDefinitions label from the second port.")
 }
diff --git a/discovery/openstack/mock_test.go b/discovery/openstack/mock_test.go
index e279b0ca8..4aa871e11 100644
--- a/discovery/openstack/mock_test.go
+++ b/discovery/openstack/mock_test.go
@@ -18,6 +18,8 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 // SDMock is the interface for the OpenStack mock.
@@ -49,15 +51,13 @@ func (m *SDMock) Setup() {
 const tokenID = "cbc36478b0bd8e67e89469c7749d4127"
 
 func testMethod(t *testing.T, r *http.Request, expected string) {
-	if expected != r.Method {
-		t.Errorf("Request method = %v, expected %v", r.Method, expected)
-	}
+	require.Equal(t, expected, r.Method, "Unexpected request method.")
 }
 
 func testHeader(t *testing.T, r *http.Request, header, expected string) {
-	if actual := r.Header.Get(header); expected != actual {
-		t.Errorf("Header %s = %s, expected %s", header, actual, expected)
-	}
+	t.Helper()
+	actual := r.Header.Get(header)
+	require.Equal(t, expected, actual, "Unexpected value for request header %s.", header)
 }
 
 // HandleVersionsSuccessfully mocks version call.
diff --git a/discovery/refresh/refresh_test.go b/discovery/refresh/refresh_test.go
index 407f0a7fa..b70a32635 100644
--- a/discovery/refresh/refresh_test.go
+++ b/discovery/refresh/refresh_test.go
@@ -97,7 +97,7 @@ func TestRefresh(t *testing.T) {
 	defer tick.Stop()
 	select {
 	case <-ch:
-		t.Fatal("Unexpected target group")
+		require.FailNow(t, "Unexpected target group")
 	case <-tick.C:
 	}
 }
diff --git a/discovery/zookeeper/zookeeper_test.go b/discovery/zookeeper/zookeeper_test.go
index d0e67b50a..c2b41ce7a 100644
--- a/discovery/zookeeper/zookeeper_test.go
+++ b/discovery/zookeeper/zookeeper_test.go
@@ -18,6 +18,7 @@ import (
 	"time"
 
 	"github.com/prometheus/common/model"
+	"github.com/stretchr/testify/require"
 	"go.uber.org/goleak"
 )
 
@@ -31,7 +32,5 @@ func TestNewDiscoveryError(t *testing.T) {
 		time.Second, []string{"/"},
 		nil,
 		func(data []byte, path string) (model.LabelSet, error) { return nil, nil })
-	if err == nil {
-		t.Fatalf("expected error, got nil")
-	}
+	require.Error(t, err)
 }