feat(duckdb): implement now() function

Author: cpcloud

ibis/backends/duckdb/registry.py

@@ -123,5 +123,6 @@ def _struct_field(t, expr):
         ops.TimestampDiff: fixed_arity('age', 2),
         ops.TimestampFromUNIX: _timestamp_from_unix,
         ops.Translate: fixed_arity('replace', 3),
+        ops.TimestampNow: fixed_arity('now', 0),
     }
 )

ibis/backends/tests/test_temporal.py

@@ -580,7 +580,7 @@ def test_day_of_week_column_group_by(
     backend.assert_frame_equal(result, expected, check_dtype=False)
 
 
-@pytest.mark.notimpl(["datafusion", "duckdb"])
+@pytest.mark.notimpl(["datafusion"])
 def test_now(backend, con):
     expr = ibis.now()
     result = con.execute(expr)
@@ -593,8 +593,8 @@ def test_now(backend, con):
 
 
 @pytest.mark.notimpl(["dask"], reason="Limit #2553")
-@pytest.mark.notimpl(["datafusion", "duckdb"])
-def test_now_from_projection(backend, con, alltypes, df):
+@pytest.mark.notimpl(["datafusion"])
+def test_now_from_projection(backend, alltypes):
     n = 5
     expr = alltypes[[ibis.now().name('ts')]].limit(n)
     result = expr.execute()