Fix testing using S3Mock

src/main/java/edu/illinois/library/cantaloupe/util/AWSClientBuilder.java

@@ -8,13 +8,10 @@
 import com.amazonaws.auth.AWSCredentials;
 import com.amazonaws.auth.AWSCredentialsProvider;
 import com.amazonaws.auth.AWSCredentialsProviderChain;
-import com.amazonaws.auth.AWSStaticCredentialsProvider;
-import com.amazonaws.auth.AnonymousAWSCredentials;
 import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
 import com.amazonaws.client.builder.AwsClientBuilder;
 import com.amazonaws.services.s3.AmazonS3;
 import com.amazonaws.services.s3.AmazonS3ClientBuilder;
-import edu.illinois.library.cantaloupe.config.ConfigurationFactory;
 
 /**
  * Creates an AWS client using the Builder pattern.
@@ -126,12 +123,6 @@ private AWSCredentialsProvider getCredentialsProvider() {
         // and use the first one that works.
         final List<AWSCredentialsProvider> providers = new ArrayList<>();
 
-        // Use anonymous credentials with S3Mock when testing.
-        // This is rather crude but will do for now.
-        if ("memory".equals(System.getProperty(ConfigurationFactory.CONFIG_VM_ARGUMENT))) {
-            providers.add(new AWSStaticCredentialsProvider(new AnonymousAWSCredentials()));
-        }
-
         // As a first resort, add a provider that draws from the application
         // configuration.
         AWSCredentialsProvider configProvider =

test.properties.sample

@@ -2,14 +2,16 @@
 # and edit that.
 
 # Used by S3SourceTest and S3CacheTest.
-# Leave blank to use a built-in mock S3 endpoint.
+# Note: to use S3Mock, leave the endpoint blank and set the keys to non-empty
+# strings.
 s3.endpoint =
-s3.access_key_id =
-s3.secret_key =
+s3.access_key_id = s3mock
+s3.secret_key = s3mock
 s3.bucket = test.cantaloupe.library.illinois.edu
 
 # Used by AzureStorageSourceTest and AzureStorageCacheTest.
-# Note: leave blank to test sas and container specified in a URL to the object key.
+# Note: leave blank to test SAS and container specified in a URL to the object
+# key.
 azurestorage.account_name =
 azurestorage.account_key =
 azurestorage.container =