diff --git a/app/Audit/ConcreteFormatters/PrePaidSummitRegistrationDiscountCodeAuditLogFormatter.php b/app/Audit/ConcreteFormatters/PrePaidSummitRegistrationDiscountCodeAuditLogFormatter.php
index 58091d486..73a32ed2e 100644
--- a/app/Audit/ConcreteFormatters/PrePaidSummitRegistrationDiscountCodeAuditLogFormatter.php
+++ b/app/Audit/ConcreteFormatters/PrePaidSummitRegistrationDiscountCodeAuditLogFormatter.php
@@ -23,6 +23,7 @@
 class PrePaidSummitRegistrationDiscountCodeAuditLogFormatter extends AbstractAuditLogFormatter
 {
 
+
     private function buildDiscountDetails(PrePaidSummitRegistrationDiscountCode $subject): string
     {
         $details = [];
@@ -90,6 +91,10 @@ public function format($subject, array $change_set): ?string
                         $discount_details,
                         $this->getUserInfo()
                     );
+
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE:
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE:
+                    return $this->formatManyToManyCollectionChange($change_set, sprintf("Pre-Paid Discount Code '%s' (%s) for Summit '%s'", $code, $id, $summit_name));
             }
         } catch (\Exception $ex) {
             Log::warning("PrePaidSummitRegistrationDiscountCodeAuditLogFormatter error: " . $ex->getMessage());
diff --git a/app/Audit/ConcreteFormatters/SponsorSummitRegistrationDiscountCodeAuditLogFormatter.php b/app/Audit/ConcreteFormatters/SponsorSummitRegistrationDiscountCodeAuditLogFormatter.php
index 63d88107c..59f27a4c5 100644
--- a/app/Audit/ConcreteFormatters/SponsorSummitRegistrationDiscountCodeAuditLogFormatter.php
+++ b/app/Audit/ConcreteFormatters/SponsorSummitRegistrationDiscountCodeAuditLogFormatter.php
@@ -22,6 +22,7 @@
 
 class SponsorSummitRegistrationDiscountCodeAuditLogFormatter extends AbstractAuditLogFormatter
 {
+
     private function buildDiscountDetails($subject): string
     {
         $details = [];
@@ -86,6 +87,10 @@ public function format($subject, array $change_set): ?string
                         $discount_details,
                         $this->getUserInfo()
                     );
+
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE:
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE:
+                    return $this->formatManyToManyCollectionChange($change_set, sprintf("Sponsor Registration Discount Code '%s' (ID: %s) in Summit '%s'", $code, $id, $summit_name));
             }
         } catch (\Exception $ex) {
             Log::warning("SponsorSummitRegistrationDiscountCodeAuditLogFormatter error: " . $ex->getMessage());
diff --git a/app/Audit/ConcreteFormatters/SponsorSummitRegistrationPromoCodeAuditLogFormatter.php b/app/Audit/ConcreteFormatters/SponsorSummitRegistrationPromoCodeAuditLogFormatter.php
index dedf9cf6a..70b11efbf 100644
--- a/app/Audit/ConcreteFormatters/SponsorSummitRegistrationPromoCodeAuditLogFormatter.php
+++ b/app/Audit/ConcreteFormatters/SponsorSummitRegistrationPromoCodeAuditLogFormatter.php
@@ -22,6 +22,7 @@
 
 class SponsorSummitRegistrationPromoCodeAuditLogFormatter extends AbstractAuditLogFormatter
 {
+
     public function format($subject, array $change_set): ?string
     {
         if (!$subject instanceof SponsorSummitRegistrationPromoCode) {
@@ -64,6 +65,10 @@ public function format($subject, array $change_set): ?string
                         $summit_name,
                         $this->getUserInfo()
                     );
+
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE:
+                case IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE:
+                    return $this->formatManyToManyCollectionChange($change_set, sprintf("Sponsor Registration Promo Code '%s' (ID: %s) in Summit '%s'", $code, $id, $summit_name));
             }
         } catch (\Exception $ex) {
             Log::warning("SponsorSummitRegistrationPromoCodeAuditLogFormatter error: " . $ex->getMessage());
diff --git a/tests/OpenTelemetry/Formatters/PrePaidSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php b/tests/OpenTelemetry/Formatters/PrePaidSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php
new file mode 100644
index 000000000..918f9a9d4
--- /dev/null
+++ b/tests/OpenTelemetry/Formatters/PrePaidSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php
@@ -0,0 +1,158 @@
+<?php
+
+namespace Tests\OpenTelemetry\Formatters;
+
+/**
+ * Copyright 2026 OpenStack Foundation
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+use App\Audit\ConcreteFormatters\PrePaidSummitRegistrationDiscountCodeAuditLogFormatter;
+use App\Audit\Interfaces\IAuditStrategy;
+use Mockery;
+use models\main\Tag;
+use models\summit\PrePaidSummitRegistrationDiscountCode;
+use models\summit\Summit;
+use models\summit\SummitBadgeFeatureType;
+use models\summit\SummitTicketType;
+use Tests\OpenTelemetry\Formatters\Support\AuditContextBuilder;
+use Tests\OpenTelemetry\Formatters\Support\PersistentCollectionTestHelper;
+use Tests\TestCase;
+
+/**
+ * PrePaidSummitRegistrationDiscountCode inherits three many-to-many collections from SummitRegistrationPromoCode: badge_features, allowed_ticket_types and tags.
+ */
+class PrePaidSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest extends TestCase
+{
+    private const MESSAGE_PREFIX = "Pre-Paid Discount Code 'PREPAID10' (40) for Summit 'Test Summit'";
+
+    protected function tearDown(): void
+    {
+        Mockery::close();
+        parent::tearDown();
+    }
+
+    public function testUpdateEventReportsAddedAndRemovedIdsFromDiff(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [10, 11], [11, 12]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) updated: Added IDs: [12], Removed IDs: [10] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventReportsAddedIds(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], [5, 6]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " allowed_ticket_types (SummitTicketType) updated: Added IDs: [5,6] by user ",
+            $result
+        );
+    }
+
+    public function testDeleteEventReportsRemovedIdsFromPayload(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], []),
+            'deleted_ids' => [3, 4],
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) deleted: Removed IDs: [3,4] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventWithoutDiffIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [3], [3]),
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testDeleteEventWithNothingToRemoveIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], []),
+            'deleted_ids' => [],
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testManyToManyEventWithoutCollectionReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format($this->makeSubject(), []));
+    }
+
+    public function testManyToManyEventWithInvalidSubjectReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format(new \stdClass(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], [7]),
+        ]));
+    }
+
+    private function makeFormatter(string $eventType): PrePaidSummitRegistrationDiscountCodeAuditLogFormatter
+    {
+        $formatter = new PrePaidSummitRegistrationDiscountCodeAuditLogFormatter($eventType);
+        $formatter->setContext(AuditContextBuilder::default()->build());
+        return $formatter;
+    }
+
+    private function makeCollection(string $field, string $targetEntity, array $snapshotIds, array $currentIds)
+    {
+        return PersistentCollectionTestHelper::buildManyToManyCollection(
+            PrePaidSummitRegistrationDiscountCode::class,
+            $field,
+            $targetEntity,
+            $snapshotIds,
+            $currentIds
+        );
+    }
+
+    private function makeSubject(): PrePaidSummitRegistrationDiscountCode
+    {
+        $summit = Mockery::mock(Summit::class);
+        $summit->shouldReceive('getName')->andReturn('Test Summit');
+
+        $code = Mockery::mock(PrePaidSummitRegistrationDiscountCode::class);
+        $code->shouldReceive('getId')->andReturn(40);
+        $code->shouldReceive('getCode')->andReturn('PREPAID10');
+        $code->shouldReceive('getRate')->andReturn(10.0);
+        $code->shouldReceive('getAmount')->andReturn(0.0);
+        $code->shouldReceive('getQuantityAvailable')->andReturn(5);
+        $code->shouldReceive('getSummit')->andReturn($summit);
+
+        return $code;
+    }
+}
diff --git a/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php b/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php
new file mode 100644
index 000000000..bbb5e97c1
--- /dev/null
+++ b/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest.php
@@ -0,0 +1,158 @@
+<?php
+
+namespace Tests\OpenTelemetry\Formatters;
+
+/**
+ * Copyright 2026 OpenStack Foundation
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+use App\Audit\ConcreteFormatters\SponsorSummitRegistrationDiscountCodeAuditLogFormatter;
+use App\Audit\Interfaces\IAuditStrategy;
+use Mockery;
+use models\main\Tag;
+use models\summit\SponsorSummitRegistrationDiscountCode;
+use models\summit\Summit;
+use models\summit\SummitBadgeFeatureType;
+use models\summit\SummitTicketType;
+use Tests\OpenTelemetry\Formatters\Support\AuditContextBuilder;
+use Tests\OpenTelemetry\Formatters\Support\PersistentCollectionTestHelper;
+use Tests\TestCase;
+
+/**
+ * SponsorSummitRegistrationDiscountCode inherits three many-to-many collections from SummitRegistrationPromoCode: badge_features, allowed_ticket_types and tags.
+ */
+class SponsorSummitRegistrationDiscountCodeManyToManyAuditLogFormatterTest extends TestCase
+{
+    private const MESSAGE_PREFIX = "Sponsor Registration Discount Code 'SPONSOR20' (ID: 41) in Summit 'Test Summit'";
+
+    protected function tearDown(): void
+    {
+        Mockery::close();
+        parent::tearDown();
+    }
+
+    public function testUpdateEventReportsAddedAndRemovedIdsFromDiff(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [10, 11], [11, 12]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) updated: Added IDs: [12], Removed IDs: [10] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventReportsAddedIds(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], [5, 6]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " allowed_ticket_types (SummitTicketType) updated: Added IDs: [5,6] by user ",
+            $result
+        );
+    }
+
+    public function testDeleteEventReportsRemovedIdsFromPayload(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], []),
+            'deleted_ids' => [3, 4],
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) deleted: Removed IDs: [3,4] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventWithoutDiffIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [3], [3]),
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testDeleteEventWithNothingToRemoveIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], []),
+            'deleted_ids' => [],
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testManyToManyEventWithoutCollectionReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format($this->makeSubject(), []));
+    }
+
+    public function testManyToManyEventWithInvalidSubjectReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format(new \stdClass(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], [7]),
+        ]));
+    }
+
+    private function makeFormatter(string $eventType): SponsorSummitRegistrationDiscountCodeAuditLogFormatter
+    {
+        $formatter = new SponsorSummitRegistrationDiscountCodeAuditLogFormatter($eventType);
+        $formatter->setContext(AuditContextBuilder::default()->build());
+        return $formatter;
+    }
+
+    private function makeCollection(string $field, string $targetEntity, array $snapshotIds, array $currentIds)
+    {
+        return PersistentCollectionTestHelper::buildManyToManyCollection(
+            SponsorSummitRegistrationDiscountCode::class,
+            $field,
+            $targetEntity,
+            $snapshotIds,
+            $currentIds
+        );
+    }
+
+    private function makeSubject(): SponsorSummitRegistrationDiscountCode
+    {
+        $summit = Mockery::mock(Summit::class);
+        $summit->shouldReceive('getName')->andReturn('Test Summit');
+
+        $code = Mockery::mock(SponsorSummitRegistrationDiscountCode::class);
+        $code->shouldReceive('getId')->andReturn(41);
+        $code->shouldReceive('getCode')->andReturn('SPONSOR20');
+        $code->shouldReceive('getSponsorId')->andReturn(7);
+        $code->shouldReceive('getRate')->andReturn(20.0);
+        $code->shouldReceive('getAmount')->andReturn(0.0);
+        $code->shouldReceive('getSummit')->andReturn($summit);
+
+        return $code;
+    }
+}
diff --git a/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationPromoCodeManyToManyAuditLogFormatterTest.php b/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationPromoCodeManyToManyAuditLogFormatterTest.php
new file mode 100644
index 000000000..6060ec499
--- /dev/null
+++ b/tests/OpenTelemetry/Formatters/SponsorSummitRegistrationPromoCodeManyToManyAuditLogFormatterTest.php
@@ -0,0 +1,156 @@
+<?php
+
+namespace Tests\OpenTelemetry\Formatters;
+
+/**
+ * Copyright 2026 OpenStack Foundation
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+use App\Audit\ConcreteFormatters\SponsorSummitRegistrationPromoCodeAuditLogFormatter;
+use App\Audit\Interfaces\IAuditStrategy;
+use Mockery;
+use models\main\Tag;
+use models\summit\SponsorSummitRegistrationPromoCode;
+use models\summit\Summit;
+use models\summit\SummitBadgeFeatureType;
+use models\summit\SummitTicketType;
+use Tests\OpenTelemetry\Formatters\Support\AuditContextBuilder;
+use Tests\OpenTelemetry\Formatters\Support\PersistentCollectionTestHelper;
+use Tests\TestCase;
+
+/**
+ * SponsorSummitRegistrationPromoCode inherits three many-to-many collections from SummitRegistrationPromoCode: badge_features, allowed_ticket_types and tags.
+ */
+class SponsorSummitRegistrationPromoCodeManyToManyAuditLogFormatterTest extends TestCase
+{
+    private const MESSAGE_PREFIX = "Sponsor Registration Promo Code 'SPONSORPROMO' (ID: 42) in Summit 'Test Summit'";
+
+    protected function tearDown(): void
+    {
+        Mockery::close();
+        parent::tearDown();
+    }
+
+    public function testUpdateEventReportsAddedAndRemovedIdsFromDiff(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [10, 11], [11, 12]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) updated: Added IDs: [12], Removed IDs: [10] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventReportsAddedIds(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], [5, 6]),
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " allowed_ticket_types (SummitTicketType) updated: Added IDs: [5,6] by user ",
+            $result
+        );
+    }
+
+    public function testDeleteEventReportsRemovedIdsFromPayload(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], []),
+            'deleted_ids' => [3, 4],
+        ]);
+
+        $this->assertStringStartsWith(
+            self::MESSAGE_PREFIX . " badge_features (SummitBadgeFeatureType) deleted: Removed IDs: [3,4] by user ",
+            $result
+        );
+    }
+
+    public function testUpdateEventWithoutDiffIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection' => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [3], [3]),
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testDeleteEventWithNothingToRemoveIsSuppressed(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_DELETE);
+
+        $result = $formatter->format($this->makeSubject(), [
+            'collection'  => $this->makeCollection('allowed_ticket_types', SummitTicketType::class, [], []),
+            'deleted_ids' => [],
+        ]);
+
+        $this->assertNull($result);
+    }
+
+    public function testManyToManyEventWithoutCollectionReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format($this->makeSubject(), []));
+    }
+
+    public function testManyToManyEventWithInvalidSubjectReturnsNull(): void
+    {
+        $formatter = $this->makeFormatter(IAuditStrategy::EVENT_COLLECTION_MANYTOMANY_UPDATE);
+
+        $this->assertNull($formatter->format(new \stdClass(), [
+            'collection' => $this->makeCollection('badge_features', SummitBadgeFeatureType::class, [], [7]),
+        ]));
+    }
+
+    private function makeFormatter(string $eventType): SponsorSummitRegistrationPromoCodeAuditLogFormatter
+    {
+        $formatter = new SponsorSummitRegistrationPromoCodeAuditLogFormatter($eventType);
+        $formatter->setContext(AuditContextBuilder::default()->build());
+        return $formatter;
+    }
+
+    private function makeCollection(string $field, string $targetEntity, array $snapshotIds, array $currentIds)
+    {
+        return PersistentCollectionTestHelper::buildManyToManyCollection(
+            SponsorSummitRegistrationPromoCode::class,
+            $field,
+            $targetEntity,
+            $snapshotIds,
+            $currentIds
+        );
+    }
+
+    private function makeSubject(): SponsorSummitRegistrationPromoCode
+    {
+        $summit = Mockery::mock(Summit::class);
+        $summit->shouldReceive('getName')->andReturn('Test Summit');
+
+        $code = Mockery::mock(SponsorSummitRegistrationPromoCode::class);
+        $code->shouldReceive('getId')->andReturn(42);
+        $code->shouldReceive('getCode')->andReturn('SPONSORPROMO');
+        $code->shouldReceive('getSponsorId')->andReturn(7);
+        $code->shouldReceive('getSummit')->andReturn($summit);
+
+        return $code;
+    }
+}