fix(internal-api): Fix test name uniqueness (#8255)

Author: PerfectSlayer

internal-api/src/test/groovy/datadog/trace/api/telemetry/MetricCollectorTest.groovy

@@ -4,7 +4,7 @@ import spock.lang.Specification
 
 class MetricCollectorTest extends Specification {
 
-  void 'test metric equality'() {
+  void 'test metric equality #iterationIndex'() {
     when:
     final sameMetric = first == second
 
@@ -23,6 +23,14 @@ class MetricCollectorTest extends Specification {
     counter(tags: ['a:b', 'c:d'], value: 2) | counter(tags: ['a:b', 'c:d'], value: 6) | true
   }
 
+  void 'test metric toString'() {
+    expect:
+    metric.toString() != null
+
+    where:
+    metric << [counter(value: 2), counter(namespace: 'other', value: 6), counter(tags: ['a:b', 'c:d'], value: 2)]
+  }
+
   private static MetricCollector.Metric counter(final Map metric) {
     metric.namespace = metric.namespace ?: 'namespace'
     metric.metric = metric.metric ?: 'metric'