go.d rename example => testrandom (#18561)

src/go/plugin/go.d/README.md

@@ -76,7 +76,6 @@ see the appropriate collector readme.
 | [dovecot](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/dovecot)                       |            Dovecot            |
 | [elasticsearch](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/elasticsearch)           |   Elasticsearch/OpenSearch    |
 | [envoy](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/envoy)                           |             Envoy             |
-| [example](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/example)                       |               -               |
 | [exim](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/exim)                             |             Exim              |
 | [fail2ban](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/fail2ban)                     |        Fail2Ban Jails         |
 | [filecheck](https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/filecheck)                   |     Files and Directories     |

src/go/plugin/go.d/config/go.d.conf

@@ -41,7 +41,6 @@ modules:
 #  dovecot: yes
 #  elasticsearch: yes
 #  envoy: yes
-#  example: no
 #  exim: yes
 #  fail2ban: yes
 #  filecheck: yes

src/go/plugin/go.d/config/go.d/example.conf

@@ -1,5 +0,0 @@
-## All available configuration options, their descriptions and default values:
-## https://github.com/netdata/netdata/tree/master/src/go/plugin/go.d/modules/example#readme
-
-jobs:
-  - name: example

src/go/plugin/go.d/modules/example/README.md

@@ -1,80 +0,0 @@
-<!--
-title: "Example module"
-description: "Use this example data collection module, which produces example charts with random values, to better understand how to build your own collector in Go."
-custom_edit_url: "https://github.com/netdata/go.d.plugin/edit/master/modules/example/README.md"
-sidebar_label: "Example module in Go"
-learn_status: "Published"
-learn_topic_type: "References"
-learn_rel_path: "Integrations/Monitor/Mock Collectors"
--->
-
-# Example module
-
-An example data collection module. Use it as an example writing a new module.
-
-## Charts
-
-This module produces example charts with random values. Number of charts, dimensions and chart type is configurable.
-
-## Configuration
-
-Edit the `go.d/example.conf` configuration file using `edit-config` from the
-Netdata [config directory](/docs/netdata-agent/configuration/README.md), which is typically at `/etc/netdata`.
-
-```bash
-cd /etc/netdata # Replace this path with your Netdata config directory
-sudo ./edit-config go.d/example.conf
-```
-
-Disabled by default. Should be explicitly enabled
-in [go.d.conf](https://github.com/netdata/netdata/blob/master/src/go/plugin/go.d/config/go.d.conf).
-
-```yaml
-# go.d.conf
-modules:
-  example: yes
-```
-
-Here is an example configuration with several jobs:
-
-```yaml
-jobs:
-  - name: example
-    charts:
-      num: 3
-      dimensions: 5
-
-  - name: hidden_example
-    hidden_charts:
-      num: 3
-      dimensions: 5
-```
-
----
-
-For all available options, see the Example
-collector's [configuration file](https://github.com/netdata/netdata/blob/master/src/go/plugin/go.d/config/go.d/example.conf).
-
-## Troubleshooting
-
-To troubleshoot issues with the `example` collector, run the `go.d.plugin` with the debug option enabled. The output
-should give you clues as to why the collector isn't working.
-
-- Navigate to the `plugins.d` directory, usually at `/usr/libexec/netdata/plugins.d/`. If that's not the case on
-  your system, open `netdata.conf` and look for the `plugins` setting under `[directories]`.
-
-  ```bash
-  cd /usr/libexec/netdata/plugins.d/
-  ```
-
-- Switch to the `netdata` user.
-
-  ```bash
-  sudo -u netdata -s
-  ```
-
-- Run the `go.d.plugin` to debug the collector:
-
-  ```bash
-  ./go.d.plugin -d -m example
-  ```

src/go/plugin/go.d/modules/example/init.go

@@ -1,64 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-
-package example
-
-import (
-	"errors"
-
-	"github.com/netdata/netdata/go/plugins/plugin/go.d/agent/module"
-)
-
-func (e *Example) validateConfig() error {
-	if e.Config.Charts.Num <= 0 && e.Config.HiddenCharts.Num <= 0 {
-		return errors.New("'charts->num' or `hidden_charts->num` must be > 0")
-	}
-	if e.Config.Charts.Num > 0 && e.Config.Charts.Dims <= 0 {
-		return errors.New("'charts->dimensions' must be > 0")
-	}
-	if e.Config.HiddenCharts.Num > 0 && e.Config.HiddenCharts.Dims <= 0 {
-		return errors.New("'hidden_charts->dimensions' must be > 0")
-	}
-	return nil
-}
-
-func (e *Example) initCharts() (*module.Charts, error) {
-	charts := &module.Charts{}
-
-	var ctx int
-	v := calcContextEvery(e.Config.Charts.Num, e.Config.Charts.Contexts)
-	for i := 0; i < e.Config.Charts.Num; i++ {
-		if i != 0 && v != 0 && ctx < (e.Config.Charts.Contexts-1) && i%v == 0 {
-			ctx++
-		}
-		chart := newChart(i, ctx, e.Config.Charts.Labels, module.ChartType(e.Config.Charts.Type))
-
-		if err := charts.Add(chart); err != nil {
-			return nil, err
-		}
-	}
-
-	ctx = 0
-	v = calcContextEvery(e.Config.HiddenCharts.Num, e.Config.HiddenCharts.Contexts)
-	for i := 0; i < e.Config.HiddenCharts.Num; i++ {
-		if i != 0 && v != 0 && ctx < (e.Config.HiddenCharts.Contexts-1) && i%v == 0 {
-			ctx++
-		}
-		chart := newHiddenChart(i, ctx, e.Config.HiddenCharts.Labels, module.ChartType(e.Config.HiddenCharts.Type))
-
-		if err := charts.Add(chart); err != nil {
-			return nil, err
-		}
-	}
-
-	return charts, nil
-}
-
-func calcContextEvery(charts, contexts int) int {
-	if contexts <= 1 {
-		return 0
-	}
-	if contexts > charts {
-		return 1
-	}
-	return charts / contexts
-}

src/go/plugin/go.d/modules/init.go

@@ -30,7 +30,6 @@ import (
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/dovecot"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/elasticsearch"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/envoy"
-	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/example"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/exim"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/fail2ban"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/filecheck"
@@ -101,6 +100,7 @@ import (
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/supervisord"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/systemdunits"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/tengine"
+	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/testrandom"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/tomcat"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/tor"
 	_ "github.com/netdata/netdata/go/plugins/plugin/go.d/modules/traefik"

src/go/plugin/go.d/modules/testrandom/charts.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-package example
+package testrandom
 
 import (
 	"fmt"
@@ -13,7 +13,7 @@ var chartTemplate = module.Chart{
 	Title: "A Random Number",
 	Units: "random",
 	Fam:   "random",
-	Ctx:   "example.random",
+	Ctx:   "testrandom.random",
 }
 
 var hiddenChartTemplate = module.Chart{
@@ -21,7 +21,7 @@ var hiddenChartTemplate = module.Chart{
 	Title: "A Random Number",
 	Units: "random",
 	Fam:   "random",
-	Ctx:   "example.random",
+	Ctx:   "testrandom.random",
 	Opts: module.Opts{
 		Hidden: true,
 	},
@@ -36,8 +36,8 @@ func newChart(num, ctx, labels int, typ module.ChartType) *module.Chart {
 	}
 	for i := 0; i < labels; i++ {
 		chart.Labels = append(chart.Labels, module.Label{
-			Key:   fmt.Sprintf("example_name_%d", i),
-			Value: fmt.Sprintf("example_value_%d_%d", num, i),
+			Key:   fmt.Sprintf("random_name_%d", i),
+			Value: fmt.Sprintf("random_value_%d_%d", num, i),
 		})
 	}
 	return chart
@@ -52,8 +52,8 @@ func newHiddenChart(num, ctx, labels int, typ module.ChartType) *module.Chart {
 	}
 	for i := 0; i < labels; i++ {
 		chart.Labels = append(chart.Labels, module.Label{
-			Key:   fmt.Sprintf("example_name_%d", i),
-			Value: fmt.Sprintf("example_value_%d_%d", num, i),
+			Key:   fmt.Sprintf("random_name_%d", i),
+			Value: fmt.Sprintf("random_value_%d_%d", num, i),
 		})
 	}
 	return chart

src/go/plugin/go.d/modules/testrandom/collect.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-package example
+package testrandom
 
 import (
 	"fmt"
@@ -8,40 +8,40 @@ import (
 	"github.com/netdata/netdata/go/plugins/plugin/go.d/agent/module"
 )
 
-func (e *Example) collect() (map[string]int64, error) {
+func (tr *TestRandom) collect() (map[string]int64, error) {
 	collected := make(map[string]int64)
 
-	for _, chart := range *e.Charts() {
-		e.collectChart(collected, chart)
+	for _, chart := range *tr.Charts() {
+		tr.collectChart(collected, chart)
 	}
 	return collected, nil
 }
 
-func (e *Example) collectChart(collected map[string]int64, chart *module.Chart) {
+func (tr *TestRandom) collectChart(collected map[string]int64, chart *module.Chart) {
 	var num int
 	if chart.Opts.Hidden {
-		num = e.Config.HiddenCharts.Dims
+		num = tr.Config.HiddenCharts.Dims
 	} else {
-		num = e.Config.Charts.Dims
+		num = tr.Config.Charts.Dims
 	}
 
 	for i := 0; i < num; i++ {
 		name := fmt.Sprintf("random%d", i)
 		id := fmt.Sprintf("%s_%s", chart.ID, name)
 
-		if !e.collectedDims[id] {
-			e.collectedDims[id] = true
+		if !tr.collectedDims[id] {
+			tr.collectedDims[id] = true
 
 			dim := &module.Dim{ID: id, Name: name}
 			if err := chart.AddDim(dim); err != nil {
-				e.Warning(err)
+				tr.Warning(err)
 			}
 			chart.MarkNotCreated()
 		}
 		if i%2 == 0 {
-			collected[id] = e.randInt()
+			collected[id] = tr.randInt()
 		} else {
-			collected[id] = -e.randInt()
+			collected[id] = -tr.randInt()
 		}
 	}
 }

src/go/plugin/go.d/modules/testrandom/init.go

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package testrandom
+
+import (
+	"errors"
+
+	"github.com/netdata/netdata/go/plugins/plugin/go.d/agent/module"
+)
+
+func (tr *TestRandom) validateConfig() error {
+	if tr.Config.Charts.Num <= 0 && tr.Config.HiddenCharts.Num <= 0 {
+		return errors.New("'charts->num' or `hidden_charts->num` must be > 0")
+	}
+	if tr.Config.Charts.Num > 0 && tr.Config.Charts.Dims <= 0 {
+		return errors.New("'charts->dimensions' must be > 0")
+	}
+	if tr.Config.HiddenCharts.Num > 0 && tr.Config.HiddenCharts.Dims <= 0 {
+		return errors.New("'hidden_charts->dimensions' must be > 0")
+	}
+	return nil
+}
+
+func (tr *TestRandom) initCharts() (*module.Charts, error) {
+	charts := &module.Charts{}
+
+	var ctx int
+	v := calcContextEvery(tr.Config.Charts.Num, tr.Config.Charts.Contexts)
+	for i := 0; i < tr.Config.Charts.Num; i++ {
+		if i != 0 && v != 0 && ctx < (tr.Config.Charts.Contexts-1) && i%v == 0 {
+			ctx++
+		}
+		chart := newChart(i, ctx, tr.Config.Charts.Labels, module.ChartType(tr.Config.Charts.Type))
+
+		if err := charts.Add(chart); err != nil {
+			return nil, err
+		}
+	}
+
+	ctx = 0
+	v = calcContextEvery(tr.Config.HiddenCharts.Num, tr.Config.HiddenCharts.Contexts)
+	for i := 0; i < tr.Config.HiddenCharts.Num; i++ {
+		if i != 0 && v != 0 && ctx < (tr.Config.HiddenCharts.Contexts-1) && i%v == 0 {
+			ctx++
+		}
+		chart := newHiddenChart(i, ctx, tr.Config.HiddenCharts.Labels, module.ChartType(tr.Config.HiddenCharts.Type))
+
+		if err := charts.Add(chart); err != nil {
+			return nil, err
+		}
+	}
+
+	return charts, nil
+}
+
+func calcContextEvery(charts, contexts int) int {
+	if contexts <= 1 {
+		return 0
+	}
+	if contexts > charts {
+		return 1
+	}
+	return charts / contexts
+}

src/go/plugin/go.d/modules/testrandom/testrandom.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-package example
+package testrandom
 
 import (
 	_ "embed"
@@ -13,7 +13,7 @@ import (
 var configSchema string
 
 func init() {
-	module.Register("example", module.Creator{
+	module.Register("testrandom", module.Creator{
 		JobConfigSchema: configSchema,
 		Defaults: module.Defaults{
 			UpdateEvery: module.UpdateEvery,
@@ -25,8 +25,8 @@ func init() {
 	})
 }
 
-func New() *Example {
-	return &Example{
+func New() *TestRandom {
+	return &TestRandom{
 		Config: Config{
 			Charts: ConfigCharts{
 				Num:  1,
@@ -58,7 +58,7 @@ type (
 	}
 )
 
-type Example struct {
+type TestRandom struct {
 	module.Base // should be embedded by every module
 	Config      `yaml:",inline"`
 
@@ -67,38 +67,38 @@ type Example struct {
 	collectedDims map[string]bool
 }
 
-func (e *Example) Configuration() any {
-	return e.Config
+func (tr *TestRandom) Configuration() any {
+	return tr.Config
 }
 
-func (e *Example) Init() error {
-	err := e.validateConfig()
+func (tr *TestRandom) Init() error {
+	err := tr.validateConfig()
 	if err != nil {
-		e.Errorf("config validation: %v", err)
+		tr.Errorf("config validation: %v", err)
 		return err
 	}
 
-	charts, err := e.initCharts()
+	charts, err := tr.initCharts()
 	if err != nil {
-		e.Errorf("charts init: %v", err)
+		tr.Errorf("charts init: %v", err)
 		return err
 	}
-	e.charts = charts
+	tr.charts = charts
 	return nil
 }
 
-func (e *Example) Check() error {
+func (tr *TestRandom) Check() error {
 	return nil
 }
 
-func (e *Example) Charts() *module.Charts {
-	return e.charts
+func (tr *TestRandom) Charts() *module.Charts {
+	return tr.charts
 }
 
-func (e *Example) Collect() map[string]int64 {
-	mx, err := e.collect()
+func (tr *TestRandom) Collect() map[string]int64 {
+	mx, err := tr.collect()
 	if err != nil {
-		e.Error(err)
+		tr.Error(err)
 	}
 
 	if len(mx) == 0 {
@@ -107,4 +107,4 @@ func (e *Example) Collect() map[string]int64 {
 	return mx
 }
 
-func (e *Example) Cleanup() {}
+func (tr *TestRandom) Cleanup() {}

src/go/plugin/go.d/modules/testrandom/testrandom_test.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-package example
+package testrandom
 
 import (
 	"os"
@@ -26,23 +26,15 @@ func Test_testDataIsValid(t *testing.T) {
 	}
 }
 
-func TestExample_ConfigurationSerialize(t *testing.T) {
-	module.TestConfigurationSerialize(t, &Example{}, dataConfigJSON, dataConfigYAML)
+func TestTestRandom_ConfigurationSerialize(t *testing.T) {
+	module.TestConfigurationSerialize(t, &TestRandom{}, dataConfigJSON, dataConfigYAML)
 }
 
 func TestNew(t *testing.T) {
-	// We want to ensure that module is a reference type, nothing more.
-
-	assert.IsType(t, (*Example)(nil), New())
+	assert.IsType(t, (*TestRandom)(nil), New())
 }
 
-func TestExample_Init(t *testing.T) {
-	// 'Init() bool' initializes the module with an appropriate config, so to test it we need:
-	// - provide the config.
-	// - set module.Config field with the config.
-	// - call Init() and compare its return value with the expected value.
-
-	// 'test' map contains different test cases.
+func TestTestRandom_Init(t *testing.T) {
 	tests := map[string]struct {
 		config   Config
 		wantFail bool
@@ -113,106 +105,87 @@ func TestExample_Init(t *testing.T) {
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			example := New()
-			example.Config = test.config
+			tr := New()
+			tr.Config = test.config
 
 			if test.wantFail {
-				assert.Error(t, example.Init())
+				assert.Error(t, tr.Init())
 			} else {
-				assert.NoError(t, example.Init())
+				assert.NoError(t, tr.Init())
 			}
 		})
 	}
 }
 
-func TestExample_Check(t *testing.T) {
-	// 'Check() bool' reports whether the module is able to collect any data, so to test it we need:
-	// - provide the module with a specific config.
-	// - initialize the module (call Init()).
-	// - call Check() and compare its return value with the expected value.
-
-	// 'test' map contains different test cases.
+func TestTestRandom_Check(t *testing.T) {
 	tests := map[string]struct {
-		prepare  func() *Example
+		prepare  func() *TestRandom
 		wantFail bool
 	}{
-		"success on default":                            {prepare: prepareExampleDefault},
-		"success when only 'charts' set":                {prepare: prepareExampleOnlyCharts},
-		"success when only 'hidden_charts' set":         {prepare: prepareExampleOnlyHiddenCharts},
-		"success when 'charts' and 'hidden_charts' set": {prepare: prepareExampleChartsAndHiddenCharts},
+		"success on default":                            {prepare: prepareTRDefault},
+		"success when only 'charts' set":                {prepare: prepareTROnlyCharts},
+		"success when only 'hidden_charts' set":         {prepare: prepareTROnlyHiddenCharts},
+		"success when 'charts' and 'hidden_charts' set": {prepare: prepareTRChartsAndHiddenCharts},
 	}
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			example := test.prepare()
-			require.NoError(t, example.Init())
+			tr := test.prepare()
+			require.NoError(t, tr.Init())
 
 			if test.wantFail {
-				assert.Error(t, example.Check())
+				assert.Error(t, tr.Check())
 			} else {
-				assert.NoError(t, example.Check())
+				assert.NoError(t, tr.Check())
 			}
 		})
 	}
 }
 
-func TestExample_Charts(t *testing.T) {
-	// We want to ensure that initialized module does not return 'nil'.
-	// If it is not 'nil' we are ok.
-
-	// 'test' map contains different test cases.
+func TestTestRandom_Charts(t *testing.T) {
 	tests := map[string]struct {
-		prepare func(t *testing.T) *Example
+		prepare func(t *testing.T) *TestRandom
 		wantNil bool
 	}{
 		"not initialized collector": {
 			wantNil: true,
-			prepare: func(t *testing.T) *Example {
+			prepare: func(t *testing.T) *TestRandom {
 				return New()
 			},
 		},
 		"initialized collector": {
-			prepare: func(t *testing.T) *Example {
-				example := New()
-				require.NoError(t, example.Init())
-				return example
+			prepare: func(t *testing.T) *TestRandom {
+				tr := New()
+				require.NoError(t, tr.Init())
+				return tr
 			},
 		},
 	}
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			example := test.prepare(t)
+			tr := test.prepare(t)
 
 			if test.wantNil {
-				assert.Nil(t, example.Charts())
+				assert.Nil(t, tr.Charts())
 			} else {
-				assert.NotNil(t, example.Charts())
+				assert.NotNil(t, tr.Charts())
 			}
 		})
 	}
 }
 
-func TestExample_Cleanup(t *testing.T) {
-	// Since this module has nothing to clean up,
-	// we want just to ensure that Cleanup() not panics.
-
+func TestTestRandom_Cleanup(t *testing.T) {
 	assert.NotPanics(t, New().Cleanup)
 }
 
-func TestExample_Collect(t *testing.T) {
-	// 'Collect() map[string]int64' returns collected data, so to test it we need:
-	// - provide the module with a specific config.
-	// - initialize the module (call Init()).
-	// - call Collect() and compare its return value with the expected value.
-
-	// 'test' map contains different test cases.
+func TestTestRandom_Collect(t *testing.T) {
 	tests := map[string]struct {
-		prepare       func() *Example
+		prepare       func() *TestRandom
 		wantCollected map[string]int64
 	}{
 		"default config": {
-			prepare: prepareExampleDefault,
+			prepare: prepareTRDefault,
 			wantCollected: map[string]int64{
 				"random_0_random0": 1,
 				"random_0_random1": -1,
@@ -221,7 +194,7 @@ func TestExample_Collect(t *testing.T) {
 			},
 		},
 		"only 'charts' set": {
-			prepare: prepareExampleOnlyCharts,
+			prepare: prepareTROnlyCharts,
 			wantCollected: map[string]int64{
 				"random_0_random0": 1,
 				"random_0_random1": -1,
@@ -236,7 +209,7 @@ func TestExample_Collect(t *testing.T) {
 			},
 		},
 		"only 'hidden_charts' set": {
-			prepare: prepareExampleOnlyHiddenCharts,
+			prepare: prepareTROnlyHiddenCharts,
 			wantCollected: map[string]int64{
 				"hidden_random_0_random0": 1,
 				"hidden_random_0_random1": -1,
@@ -251,7 +224,7 @@ func TestExample_Collect(t *testing.T) {
 			},
 		},
 		"'charts' and 'hidden_charts' set": {
-			prepare: prepareExampleChartsAndHiddenCharts,
+			prepare: prepareTRChartsAndHiddenCharts,
 			wantCollected: map[string]int64{
 				"hidden_random_0_random0": 1,
 				"hidden_random_0_random1": -1,
@@ -279,41 +252,23 @@ func TestExample_Collect(t *testing.T) {
 
 	for name, test := range tests {
 		t.Run(name, func(t *testing.T) {
-			example := test.prepare()
-			require.NoError(t, example.Init())
+			tr := test.prepare()
+			require.NoError(t, tr.Init())
 
-			collected := example.Collect()
+			mx := tr.Collect()
 
-			assert.Equal(t, test.wantCollected, collected)
-			ensureCollectedHasAllChartsDimsVarsIDs(t, example, collected)
+			assert.Equal(t, test.wantCollected, mx)
+			module.TestMetricsHasAllChartsDims(t, tr.Charts(), mx)
 		})
 	}
 }
 
-func ensureCollectedHasAllChartsDimsVarsIDs(t *testing.T, e *Example, collected map[string]int64) {
-	for _, chart := range *e.Charts() {
-		if chart.Obsolete {
-			continue
-		}
-		for _, dim := range chart.Dims {
-			_, ok := collected[dim.ID]
-			assert.Truef(t, ok,
-				"collected metrics has no data for dim '%s' chart '%s'", dim.ID, chart.ID)
-		}
-		for _, v := range chart.Vars {
-			_, ok := collected[v.ID]
-			assert.Truef(t, ok,
-				"collected metrics has no data for var '%s' chart '%s'", v.ID, chart.ID)
-		}
-	}
+func prepareTRDefault() *TestRandom {
+	return prepareTR(New().Config)
 }
 
-func prepareExampleDefault() *Example {
-	return prepareExample(New().Config)
-}
-
-func prepareExampleOnlyCharts() *Example {
-	return prepareExample(Config{
+func prepareTROnlyCharts() *TestRandom {
+	return prepareTR(Config{
 		Charts: ConfigCharts{
 			Num:  2,
 			Dims: 5,
@@ -321,8 +276,8 @@ func prepareExampleOnlyCharts() *Example {
 	})
 }
 
-func prepareExampleOnlyHiddenCharts() *Example {
-	return prepareExample(Config{
+func prepareTROnlyHiddenCharts() *TestRandom {
+	return prepareTR(Config{
 		HiddenCharts: ConfigCharts{
 			Num:  2,
 			Dims: 5,
@@ -330,8 +285,8 @@ func prepareExampleOnlyHiddenCharts() *Example {
 	})
 }
 
-func prepareExampleChartsAndHiddenCharts() *Example {
-	return prepareExample(Config{
+func prepareTRChartsAndHiddenCharts() *TestRandom {
+	return prepareTR(Config{
 		Charts: ConfigCharts{
 			Num:  2,
 			Dims: 5,
@@ -343,9 +298,9 @@ func prepareExampleChartsAndHiddenCharts() *Example {
 	})
 }
 
-func prepareExample(cfg Config) *Example {
-	example := New()
-	example.Config = cfg
-	example.randInt = func() int64 { return 1 }
-	return example
+func prepareTR(cfg Config) *TestRandom {
+	tr := New()
+	tr.Config = cfg
+	tr.randInt = func() int64 { return 1 }
+	return tr
 }