[chore] small fixes in hostmetrics, no need of using mocks

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

receiver/hostmetricsreceiver/hostmetrics_receiver_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/require"
-	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/consumer/consumertest"
@@ -222,24 +221,14 @@ func (m *mockConfig) SetRootPath(_ string) {}
 
 func (m *mockConfig) SetEnvMap(_ common.EnvMap) {}
 
-type (
-	mockFactory struct{ mock.Mock }
-	mockScraper struct{ mock.Mock }
-)
+type mockFactory struct{ mock.Mock }
 
 func (m *mockFactory) CreateDefaultConfig() internal.Config { return &mockConfig{} }
 func (m *mockFactory) CreateMetricsScraper(context.Context, receiver.Settings, internal.Config) (scraperhelper.Scraper, error) {
 	args := m.MethodCalled("CreateMetricsScraper")
 	return args.Get(0).(scraperhelper.Scraper), args.Error(1)
 }
 
-func (m *mockScraper) ID() component.ID                            { return component.MustNewID("mock_scraper") }
-func (m *mockScraper) Start(context.Context, component.Host) error { return nil }
-func (m *mockScraper) Shutdown(context.Context) error              { return nil }
-func (m *mockScraper) Scrape(context.Context) (pmetric.Metrics, error) {
-	return pmetric.NewMetrics(), errors.New("err1")
-}
-
 func TestGatherMetrics_ScraperKeyConfigError(t *testing.T) {
 	tmp := scraperFactories
 	scraperFactories = map[string]internal.ScraperFactory{}
@@ -255,7 +244,7 @@ func TestGatherMetrics_ScraperKeyConfigError(t *testing.T) {
 
 func TestGatherMetrics_CreateMetricsScraperError(t *testing.T) {
 	mFactory := &mockFactory{}
-	mFactory.On("CreateMetricsScraper").Return(&mockScraper{}, errors.New("err1"))
+	mFactory.On("CreateMetricsScraper").Return(nil, errors.New("err1"))
 	tmp := scraperFactories
 	scraperFactories = map[string]internal.ScraperFactory{mockTypeStr: mFactory}
 	defer func() {