From efec48700f3cef2755aeb3cf9fac06029f4f0842 Mon Sep 17 00:00:00 2001
From: Doug Davis <ddavis@anaconda.com>
Date: Fri, 21 Jul 2023 10:55:20 -0500
Subject: [PATCH] add xfailing test

---
 src/dask_awkward/lib/unproject_layout.py |  7 +++----
 tests/test_core.py                       | 25 +++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/dask_awkward/lib/unproject_layout.py b/src/dask_awkward/lib/unproject_layout.py
index 0f8c3e51f..1235a4189 100644
--- a/src/dask_awkward/lib/unproject_layout.py
+++ b/src/dask_awkward/lib/unproject_layout.py
@@ -403,7 +403,6 @@ def unproject_layout(form: Form | None, layout: Content) -> Content:
         not appear in the projected layout will be PlaceholderArrays).
 
     """
-    return layout
-    # if form is None:
-    #     return layout
-    # return _unproject_layout(form, layout, layout.length, layout.backend)
+    if form is None:
+        return layout
+    return _unproject_layout(form, layout, layout.length, layout.backend)
diff --git a/tests/test_core.py b/tests/test_core.py
index 6cabf533b..0416a4722 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -2,10 +2,11 @@
 
 import copy
 from collections import namedtuple
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Callable
 
 import awkward as ak
 import dask.array as da
+import dask.config
 import fsspec
 import numpy as np
 import pytest
@@ -826,3 +827,25 @@ def test_map_partitions_no_dask_collections_passed(caa):
         match="map_partitions expects at least one Dask collection",
     ):
         dak.num(caa.points.x, axis=1)
+
+
+@pytest.mark.parametrize("fn", [dak.count, dak.zeros_like, dak.ones_like])
+@pytest.mark.parametrize(
+    "opt_enabled",
+    [
+        pytest.param(
+            True, marks=pytest.mark.xfail(reason="these fail with opt enabled")
+        ),
+        False,
+    ],
+)
+def test_shape_only_ops(
+    fn: Callable, opt_enabled: bool, tmp_path_factory: pytest.TempPathFactory
+) -> None:
+    a = ak.Array([{"a": 1, "b": 2}, {"a": 3, "b": 4}])
+    p = tmp_path_factory.mktemp("zeros-like-flat")
+    ak.to_parquet(a, str(p / "file.parquet"))
+    lazy = dak.from_parquet(str(p))
+    result = fn(lazy.b)
+    with dask.config.set({"awkward.optimization.enabled": opt_enabled}):
+        result.compute()