Fix ArrayStore field_desc test (#404)

## Description

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Oops

## TODO

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[CONTRIBUTING.md](https://github.com/icaros-usc/pyribs/blob/master/CONTRIBUTING.md)
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HISTORY.md

@@ -11,7 +11,7 @@
 - **Backwards-incompatible:** Rename `measure_*` columns to `measures_*` in
   `as_pandas` ({pr}`396`)
 - Add ArrayStore data structure ({pr}`395`, {pr}`398`, {pr}`400`, {pr}`402`,
-  {pr}`403`)
+  {pr}`403`, {pr}`404`)
 - Add GradientOperatorEmitter to support OMG-MEGA and OG-MAP-Elites ({pr}`348`)
 
 #### Improvements

tests/archives/array_store_test.py

@@ -47,8 +47,10 @@ def test_init(shape):
     assert len(store.occupied_list) == 0
     assert store.field_desc == {
         "objective": (shape[0], np.float32),
-        "measures": ((shape[1],), np.float32),
-        "solution": ((shape[2],), np.float32),
+        "measures": (
+            (shape[1],) if isinstance(shape[1], int) else shape[1], np.float32),
+        "solution": (
+            (shape[2],) if isinstance(shape[2], int) else shape[2], np.float32),
     }