tests: shrink and regrow datasets allocated early

Datasets with early allocation and unlimited dimensions (Extensible
Array, version-2 B-tree, version-1 B-tree under earliest), unfiltered
and deflated: the random resize workload gives the values h5py gets and
the same chunk index shape, with every chunk a growth brings in
allocated and filled as H5D__chunk_allocate does.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

crates/clawhdf5-tools/tests/edit_coverage_interop.rs

@@ -717,6 +717,42 @@ fn shrink_matches_libhdf5() {
         false,
         99,
     );
+    // Early allocation with unlimited dimensions (Extensible Array,
+    // version-2 B-tree; version-1 B-tree under `earliest`), filtered and
+    // not: growth allocates and fills every new chunk, as libhdf5 does.
+    for (i, (lv, dump)) in [("'earliest'", true), ("'v110'", true), ("'latest'", false)]
+        .iter()
+        .enumerate()
+    {
+        for (j, (max, z)) in [
+            ("(None, 9)", ""),
+            ("(None, None)", ""),
+            ("(None, 9)", ", compression='gzip'"),
+            ("(None, None)", ", compression='gzip'"),
+        ]
+        .iter()
+        .enumerate()
+        {
+            shrink_workload(
+                &format!("early_{i}_{j}"),
+                lv,
+                &format!(
+                    "\x20   f.create_dataset('x', data=np.arange(72, dtype='<i4').reshape(8, 9), \
+                     maxshape={max}, chunks=(3, 4), fillvalue=-4{z})\n\
+                     \x20   dcpl = f['x'].id.get_create_plist()\n\
+                     \x20   del f['x']\n\
+                     \x20   dcpl.set_alloc_time(h5d.ALLOC_TIME_EARLY)\n\
+                     \x20   h5d.create(f.id, b'x', h5t.STD_I32LE, \
+                     h5s.create_simple((8, 9), tuple(h5s.UNLIMITED if m is None else m for m in {max})), \
+                     dcpl=dcpl)\n\
+                     \x20   f['x'][...] = np.arange(72, dtype='<i4').reshape(8, 9)\n"
+                ),
+                -4,
+                *dump,
+                200 + (i * 4 + j) as u64,
+            );
+        }
+    }
 }
 
 /// An implicit chunk index (early allocation, no filters, fixed maximum