From 41c9f42b362df6232f4a879695adce56c80b7ffe Mon Sep 17 00:00:00 2001
From: Drew Leonard <andy.j.leonard@gmail.com>
Date: Wed, 18 Sep 2024 11:38:03 +0100
Subject: [PATCH] Check that file manager values match all tiles

---
 dkist/dataset/tests/test_tiled_dataset.py |  6 +++++
 dkist/dataset/tiled_dataset.py            | 29 +++++++++++++++++------
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/dkist/dataset/tests/test_tiled_dataset.py b/dkist/dataset/tests/test_tiled_dataset.py
index 32f5c4363..45c430922 100644
--- a/dkist/dataset/tests/test_tiled_dataset.py
+++ b/dkist/dataset/tests/test_tiled_dataset.py
@@ -105,3 +105,9 @@ def test_file_manager(large_tiled_dataset):
     # Have some slicing tests here
     assert len(ds.slice_tiles[0].files.filenames) == 9
     assert len(ds[:2, :2].files.filenames) == 12
+
+    # TODO Also test that the other checks raise errors
+    # This at least demonstrates that the structure works
+    ds[1, 1].files.fileuri_array.dtype = np.dtype("<i")
+    with pytest.raises(AssertionError, match="must be the same across all tiles"):
+        ds.files
diff --git a/dkist/dataset/tiled_dataset.py b/dkist/dataset/tiled_dataset.py
index 5f9547fe8..cd9474e1b 100644
--- a/dkist/dataset/tiled_dataset.py
+++ b/dkist/dataset/tiled_dataset.py
@@ -203,14 +203,29 @@ def files(self):
 
     @property
     def _file_manager(self):
+        fileuris = [[tile.files.filenames for tile in row] for row in self]
+        dtype = self[0, 0].files.fileuri_array.dtype
+        shape = self[0, 0].files.shape
+        basepath = self[0, 0].files.basepath
+        chunksize = self[0, 0]._data.chunksize
+
+        for tile in self.flat:
+            try:
+                assert dtype == tile.files.fileuri_array.dtype
+                assert shape == tile.files.shape
+                assert basepath == tile.files.basepath
+                assert chunksize == tile._data.chunksize
+            except AssertionError as err:
+                raise AssertionError("Attributes of TiledDataset.FileManager must be the same across all tiles.") from err
+
         return FileManager(
             StripedExternalArray(
-                fileuris = [[tile.files.filenames for tile in row] for row in self],
-                target = 1,
-                dtype = self[0, 0].files.fileuri_array.dtype,
-                shape = self[0, 0]._data.chunksize,
-                loader = AstropyFITSLoader,
-                basepath = self[0, 0].files.basepath,
-                chunksize = self[0, 0]._data.chunksize
+                fileuris=fileuris,
+                target=1,
+                dtype=dtype,
+                shape=shape,
+                loader=AstropyFITSLoader,
+                basepath=basepath,
+                chunksize=chunksize
             )
         )