Implement partial prefix support for Atmos

Atmos only supports listing by directories while other blobstores
allow listing via arbitrary prefixes.  Allow requests which list
directories via both prefix and delimiter = "/" to succeed instead of
failing all requests.  Also change a test which specified recursive to
instead be delimiter = "/".  Fixes gaul/s3proxy#244.

apis/atmos/src/main/java/org/jclouds/atmos/blobstore/AtmosBlobStore.java

@@ -220,8 +220,15 @@ public class AtmosBlobStore extends BaseBlobStore {
    @Override
    public PageSet<? extends StorageMetadata> list(String container,
             org.jclouds.blobstore.options.ListContainerOptions options) {
-      checkArgument(Strings.isNullOrEmpty(options.getPrefix()), "does not support prefixes");
+      // TODO: recursive?
+      if (!Strings.nullToEmpty(options.getDelimiter()).equals("/") && !Strings.isNullOrEmpty(options.getPrefix())) {
+         throw new IllegalArgumentException("Atmos can only list via prefix if delimiter is / and the prefix matches an existing directory");
+      }
       container = AtmosUtils.adjustContainerIfDirOptionPresent(container, options);
+      if (!Strings.isNullOrEmpty(options.getPrefix())) {
+         // this only works when the prefix exactly matches a directory, the common usage
+         container += "/" + options.getPrefix();
+      }
       ListOptions nativeOptions = container2ContainerListOptions.apply(options);
       // until includeMeta() option works for namespace interface
       PageSet<? extends StorageMetadata> list = container2ResourceList.apply(sync.listDirectory(container,

apis/atmos/src/test/java/org/jclouds/atmos/blobstore/integration/AtmosContainerIntegrationLiveTest.java

@@ -58,16 +58,11 @@ public class AtmosContainerIntegrationLiveTest extends BaseContainerIntegrationT
 
    @Override
    public void testContainerListWithPrefix() {
-      throw new SkipException("Prefix option has not been plumbed down to Atmos");
+      throw new SkipException("Atmos can only list prefix which matches an existing directory");
    }
 
    @Override
    public void testDelimiterList() {
       throw new SkipException("Delimiter support is not yet implemented");
    }
-
-   @Override
-   public void testListContainerPrefix() throws InterruptedException {
-      throw new SkipException("Prefix support is not yet implemented");
-   }
 }

blobstore/src/test/java/org/jclouds/blobstore/integration/internal/BaseContainerIntegrationTest.java

@@ -310,7 +310,7 @@ public class BaseContainerIntegrationTest extends BaseBlobStoreIntegrationTest {
          add15UnderRoot(containerName);
          awaitConsistency();
          PageSet<? extends StorageMetadata> container = view.getBlobStore().list(
-               containerName, new ListContainerOptions().recursive().prefix(prefix));
+               containerName, new ListContainerOptions().prefix(prefix).delimiter("/"));
          assert container.getNextMarker() == null;
          assertEquals(container.size(), 10);
       } finally {