Fix NamespaceExists test failure (#1956)

* Drop test databases between Micrometer tracing tests

---------

Co-authored-by: Ross Lawley <ross@mongodb.com>

Author: nhachicha

driver-reactive-streams/src/test/functional/com/mongodb/reactivestreams/client/unified/MicrometerTracingTest.java

@@ -16,12 +16,21 @@
 
 package com.mongodb.reactivestreams.client.unified;
 
+import com.mongodb.client.unified.UnifiedTestModifications.TestDef;
 import org.junit.jupiter.params.provider.Arguments;
 
 import java.util.Collection;
 
+import static com.mongodb.client.Fixture.getMongoClient;
+
 final class MicrometerTracingTest extends UnifiedReactiveStreamsTest {
     private static Collection<Arguments> data() {
         return getTestData("open-telemetry/tests");
     }
+
+    @Override
+    protected void postCleanUp(final TestDef testDef) {
+        super.postCleanUp(testDef);
+        getEntities().getDatabaseNames().forEach(name -> getMongoClient().getDatabase(name).drop());
+    }
 }

driver-sync/src/test/functional/com/mongodb/client/unified/Entities.java

@@ -189,6 +189,12 @@ public MongoDatabase getDatabase(final String id) {
         return getEntity(id, databases, "database");
     }
 
+    public Set<String> getDatabaseNames() {
+        return databases.values().stream()
+                .map(MongoDatabase::getName)
+                .collect(Collectors.toSet());
+    }
+
     public boolean hasCollection(final String id) {
         return collections.containsKey(id);
     }

driver-sync/src/test/functional/com/mongodb/client/unified/MicrometerTracingTest.java

@@ -16,12 +16,21 @@
 
 package com.mongodb.client.unified;
 
+import com.mongodb.client.unified.UnifiedTestModifications.TestDef;
 import org.junit.jupiter.params.provider.Arguments;
 
 import java.util.Collection;
 
+import static com.mongodb.client.Fixture.getMongoClient;
+
 final class MicrometerTracingTest extends UnifiedSyncTest {
     private static Collection<Arguments> data() {
         return getTestData("open-telemetry/tests");
     }
+
+    @Override
+    protected void postCleanUp(final TestDef testDef) {
+        super.postCleanUp(testDef);
+        getEntities().getDatabaseNames().forEach(name -> getMongoClient().getDatabase(name).drop());
+    }
 }