chore(tests): assert StorageClass#STANDARD in some responses

Some S3 APIs return STANDARD, while others do not.
Just ran these tests against S3 APIs and they pass.

See also #2736

Author: afranken

integration-tests/src/test/kotlin/com/adobe/testing/s3mock/its/GetPutDeleteObjectIT.kt

@@ -536,7 +536,7 @@ internal class GetPutDeleteObjectIT : S3TestBase() {
         )
       }.also {
         assertThat(it.eTag()).isEqualTo(eTag.trim('"'))
-        // default storageClass is STANDARD, which is never returned from APIs except by GetObjectAttributes
+        // GetObjectAttributes returns the default storageClass "STANDARD", even though other APIs may not.
         assertThat(it.storageClass()).isEqualTo(StorageClass.STANDARD)
         assertThat(it.objectSize()).isEqualTo(UPLOAD_FILE_LENGTH)
         assertThat(it.checksum().checksumSHA1()).isEqualTo(expectedChecksum)

integration-tests/src/test/kotlin/com/adobe/testing/s3mock/its/ListObjectsIT.kt

@@ -29,6 +29,7 @@ import software.amazon.awssdk.services.s3.model.ChecksumAlgorithm
 import software.amazon.awssdk.services.s3.model.CommonPrefix
 import software.amazon.awssdk.services.s3.model.EncodingType
 import software.amazon.awssdk.services.s3.model.NoSuchBucketException
+import software.amazon.awssdk.services.s3.model.ObjectStorageClass
 import software.amazon.awssdk.services.s3.model.S3Object
 import software.amazon.awssdk.utils.http.SdkHttpUtils
 
@@ -103,6 +104,14 @@ internal class ListObjectsIT : S3TestBase() {
             Tuple(arrayListOf(ChecksumAlgorithm.SHA256)),
             Tuple(arrayListOf(ChecksumAlgorithm.SHA256)),
           )
+        // ListObjects returns the default storageClass "STANDARD", even though other APIs may not.
+        assertThat(it.contents())
+          .hasSize(2)
+          .extracting(S3Object::storageClass)
+          .containsOnly(
+            Tuple(ObjectStorageClass.STANDARD),
+            Tuple(ObjectStorageClass.STANDARD),
+          )
       }
   }
 
@@ -168,6 +177,8 @@ internal class ListObjectsIT : S3TestBase() {
         listing.contents().also {
           assertThat(it).hasSize(1)
           assertThat(it[0].key()).isEqualTo(key)
+          // ListObjectsV2 returns the default storageClass "STANDARD", even though other APIs may not.
+          assertThat(it[0].storageClass()).isEqualTo(ObjectStorageClass.STANDARD)
         }
       }
   }

integration-tests/src/test/kotlin/com/adobe/testing/s3mock/its/VersionsIT.kt

@@ -27,6 +27,7 @@ import software.amazon.awssdk.services.s3.S3Client
 import software.amazon.awssdk.services.s3.model.BucketVersioningStatus
 import software.amazon.awssdk.services.s3.model.ChecksumAlgorithm
 import software.amazon.awssdk.services.s3.model.ObjectAttributes
+import software.amazon.awssdk.services.s3.model.ObjectVersionStorageClass
 import software.amazon.awssdk.services.s3.model.S3Exception
 import software.amazon.awssdk.services.s3.model.StorageClass
 
@@ -100,7 +101,7 @@ internal class VersionsIT : S3TestBase() {
         )
       }.also {
         assertThat(it.versionId()).isEqualTo(versionId)
-        // default storageClass is STANDARD, which is never returned from APIs
+        // GetObjectAttributes returns the default storageClass "STANDARD", even though other APIs may not.
         assertThat(it.storageClass()).isEqualTo(StorageClass.STANDARD)
         assertThat(it.objectSize()).isEqualTo(UPLOAD_FILE_LENGTH)
         assertThat(it.checksum().checksumSHA1()).isEqualTo(expectedChecksum)
@@ -260,6 +261,8 @@ internal class VersionsIT : S3TestBase() {
     assertThat(listObjectVersions.hasVersions()).isTrue
     assertThat(listObjectVersions.versions()[0].key()).isEqualTo(UPLOAD_FILE_NAME)
     assertThat(listObjectVersions.versions()[0].versionId()).isEqualTo(versionId)
+    // ListObjectVersions returns the default storageClass "STANDARD", even though other APIs may not.
+    assertThat(listObjectVersions.versions()[0].storageClass()).isEqualTo(ObjectVersionStorageClass.STANDARD)
 
     assertThatThrownBy {
       s3Client.getObject {