test(backend): add ops.StructColumn test

ibis/backends/tests/test_struct.py

@@ -5,6 +5,7 @@
 from pytest import param
 
 import ibis
+import ibis.expr.datatypes as dt
 
 pytestmark = [
     pytest.mark.never(["mysql", "sqlite"], reason="No struct support"),
@@ -67,3 +68,19 @@ def test_literal(con, field, expr_fn, expected_fn):
     result = pd.Series([con.execute(query)]).replace(np.nan, None)
     expected = pd.Series([expected_fn(field)])
     tm.assert_series_equal(result, expected)
+
+
+@pytest.mark.notimpl(["dask", "pandas", "postgres"])
+def test_struct_column(con):
+    t = con.table("functional_alltypes")
+    df = t.execute()
+    expr = ibis.struct(dict(a=t.string_col, b=1, c=t.int_col)).name("s")
+    assert expr.type() == dt.Struct.from_dict(
+        dict(a=dt.string, b=dt.int8, c=dt.int32)
+    )
+    result = expr.execute()
+    expected = pd.Series(
+        (dict(a=a, b=1, c=c) for a, c in zip(df.string_col, df.int_col)),
+        name="s",
+    )
+    tm.assert_series_equal(result, expected)