fix s3 store get range

Author: brokkoli71

src/main/java/dev/zarr/zarrjava/store/S3Store.java

@@ -71,7 +71,7 @@ public ByteBuffer get(String[] keys, long start) {
     GetObjectRequest req = GetObjectRequest.builder()
     .bucket(bucketName)
     .key(resolveKeys(keys))
-    .range(String.valueOf(start))
+    .range(String.format("bytes=%d-", start))
     .build();
     return get(req);
   }
@@ -82,7 +82,7 @@ public ByteBuffer get(String[] keys, long start, long end) {
     GetObjectRequest req = GetObjectRequest.builder()
     .bucket(bucketName)
     .key(resolveKeys(keys))
-    .range(start +"-"+ end)
+    .range(String.format("bytes=%d-%d", start, end-1)) // S3 range is inclusive
     .build();
     return get(req);
   }

src/test/java/dev/zarr/zarrjava/ZarrStoreTest.java

@@ -86,6 +86,24 @@ public void testS3Store() throws IOException, ZarrException {
         Assertions.assertEquals(0, arrayCore.read(new long[]{0,0,0,0}, new int[]{1,1,1,1}).getInt(0));
     }
 
+    @Test
+    public void testS3StoreGet() throws IOException, ZarrException {
+        S3Store s3Store = new S3Store(S3Client.builder()
+                .region(Region.of("eu-west-1"))
+                .credentialsProvider(AnonymousCredentialsProvider.create())
+                .build(), "static.webknossos.org", "data");
+        String[] keys = new String[]{"zarr_v3", "l4_sample", "color", "1", "zarr.json"};
+
+        ByteBuffer buffer = s3Store.get(keys);
+        ByteBuffer bufferWithStart = s3Store.get(keys, 10);
+        Assertions.assertEquals(10, buffer.remaining()-bufferWithStart.remaining());
+
+        ByteBuffer bufferWithStartAndEnd = s3Store.get(keys, 0, 10);
+        Assertions.assertEquals(10, bufferWithStartAndEnd.remaining());
+
+    }
+
+
     @Test
     public void testHttpStore() throws IOException, ZarrException {
         HttpStore httpStore = new dev.zarr.zarrjava.store.HttpStore("https://static.webknossos.org/data/zarr_v3/l4_sample");