[chore][exporter/datadog] fix integration test (#38091)

#### Description

#36873
the prometheus receiver can now keep dots in metric names rather than
converting them to underscores. E.g. say there is a metric `my.metric`
scraped from prometheus receiver, its name is `my_metric` before 0.120.0
vs. `my.metric` now. This should have broken some datadog integration
tests, but those are skipped in race detector (which is always on in
CIs) so the failures did not show up in CIs.

Author: songy23

exporter/datadogexporter/integrationtest/no_race_integration_test.go

@@ -14,81 +14,29 @@ import (
 
 	"github.com/DataDog/datadog-agent/comp/otelcol/otlp/testutil"
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"go.opentelemetry.io/collector/featuregate"
 
 	commonTestutil "github.com/open-telemetry/opentelemetry-collector-contrib/internal/common/testutil"
-	pkgdatadog "github.com/open-telemetry/opentelemetry-collector-contrib/pkg/datadog"
 )
 
-func TestIntegrationInternalMetrics_WithRemapping(t *testing.T) {
-	prevVal := pkgdatadog.MetricRemappingDisabledFeatureGate.IsEnabled()
-	require.NoError(t, featuregate.GlobalRegistry().Set(pkgdatadog.MetricRemappingDisabledFeatureGate.ID(), false))
-	defer func() {
-		require.NoError(t, featuregate.GlobalRegistry().Set(pkgdatadog.MetricRemappingDisabledFeatureGate.ID(), prevVal))
-	}()
-
-	expectedMetrics := map[string]struct{}{
-		// Datadog internal metrics on trace and stats writers, with the otelcol_ prefix
-		"otelcol_datadog_otlp_translator_resources_missing_source": {},
-		"otelcol_datadog_trace_agent_stats_writer_bytes":           {},
-		"otelcol_datadog_trace_agent_stats_writer_retries":         {},
-		"otelcol_datadog_trace_agent_stats_writer_stats_buckets":   {},
-		"otelcol_datadog_trace_agent_stats_writer_stats_entries":   {},
-		"otelcol_datadog_trace_agent_stats_writer_payloads":        {},
-		"otelcol_datadog_trace_agent_stats_writer_client_payloads": {},
-		"otelcol_datadog_trace_agent_stats_writer_errors":          {},
-		"otelcol_datadog_trace_agent_stats_writer_splits":          {},
-		"otelcol_datadog_trace_agent_trace_writer_bytes":           {},
-		"otelcol_datadog_trace_agent_trace_writer_retries":         {},
-		"otelcol_datadog_trace_agent_trace_writer_spans":           {},
-		"otelcol_datadog_trace_agent_trace_writer_traces":          {},
-		"otelcol_datadog_trace_agent_trace_writer_payloads":        {},
-		"otelcol_datadog_trace_agent_trace_writer_errors":          {},
-		"otelcol_datadog_trace_agent_trace_writer_events":          {},
-
-		// OTel collector internal metrics
-		"otelcol_process_memory_rss":                     {},
-		"otelcol_process_runtime_total_sys_memory_bytes": {},
-		"otelcol_process_uptime":                         {},
-		"otelcol_process_cpu_seconds":                    {},
-		"otelcol_process_runtime_heap_alloc_bytes":       {},
-		"otelcol_process_runtime_total_alloc_bytes":      {},
-		"otelcol_receiver_accepted_metric_points":        {},
-		"otelcol_receiver_accepted_spans":                {},
-		"otelcol_exporter_queue_capacity":                {},
-		"otelcol_exporter_queue_size":                    {},
-		"otelcol_exporter_sent_spans":                    {},
-		"otelcol_exporter_sent_metric_points":            {},
-	}
-	testIntegrationInternalMetrics(t, expectedMetrics)
-}
-
-func TestIntegrationInternalMetrics_WithoutRemapping(t *testing.T) {
-	prevVal := pkgdatadog.MetricRemappingDisabledFeatureGate.IsEnabled()
-	require.NoError(t, featuregate.GlobalRegistry().Set(pkgdatadog.MetricRemappingDisabledFeatureGate.ID(), true))
-	defer func() {
-		require.NoError(t, featuregate.GlobalRegistry().Set(pkgdatadog.MetricRemappingDisabledFeatureGate.ID(), prevVal))
-	}()
-
+func TestIntegrationInternalMetrics(t *testing.T) {
 	expectedMetrics := map[string]struct{}{
 		// Datadog internal metrics on trace and stats writers
-		"datadog_otlp_translator_resources_missing_source": {},
-		"datadog_trace_agent_stats_writer_bytes":           {},
-		"datadog_trace_agent_stats_writer_retries":         {},
-		"datadog_trace_agent_stats_writer_stats_buckets":   {},
-		"datadog_trace_agent_stats_writer_stats_entries":   {},
-		"datadog_trace_agent_stats_writer_payloads":        {},
-		"datadog_trace_agent_stats_writer_client_payloads": {},
-		"datadog_trace_agent_stats_writer_errors":          {},
-		"datadog_trace_agent_stats_writer_splits":          {},
-		"datadog_trace_agent_trace_writer_bytes":           {},
-		"datadog_trace_agent_trace_writer_retries":         {},
-		"datadog_trace_agent_trace_writer_spans":           {},
-		"datadog_trace_agent_trace_writer_traces":          {},
-		"datadog_trace_agent_trace_writer_payloads":        {},
-		"datadog_trace_agent_trace_writer_errors":          {},
-		"datadog_trace_agent_trace_writer_events":          {},
+		"datadog.otlp_translator.resources.missing_source": {},
+		"datadog.trace_agent.stats_writer.bytes":           {},
+		"datadog.trace_agent.stats_writer.retries":         {},
+		"datadog.trace_agent.stats_writer.stats_buckets":   {},
+		"datadog.trace_agent.stats_writer.stats_entries":   {},
+		"datadog.trace_agent.stats_writer.payloads":        {},
+		"datadog.trace_agent.stats_writer.client_payloads": {},
+		"datadog.trace_agent.stats_writer.errors":          {},
+		"datadog.trace_agent.stats_writer.splits":          {},
+		"datadog.trace_agent.trace_writer.bytes":           {},
+		"datadog.trace_agent.trace_writer.retries":         {},
+		"datadog.trace_agent.trace_writer.spans":           {},
+		"datadog.trace_agent.trace_writer.traces":          {},
+		"datadog.trace_agent.trace_writer.payloads":        {},
+		"datadog.trace_agent.trace_writer.errors":          {},
+		"datadog.trace_agent.trace_writer.events":          {},
 
 		// OTel collector internal metrics
 		"otelcol_process_memory_rss":                     {},