fix(mssql): fix round without argument

ibis/backends/mssql/registry.py

@@ -74,6 +74,15 @@ def translator(t, op):
     return translator
 
 
+def _round(t, op):
+    sa_arg = t.translate(op.arg)
+
+    if op.digits is not None:
+        return sa.func.round(sa_arg, t.translate(op.digits))
+    else:
+        return sa.func.round(sa_arg, 0)
+
+
 operation_registry = sqlalchemy_operation_registry.copy()
 operation_registry.update(sqlalchemy_window_functions_registry)
 
@@ -113,6 +122,7 @@ def translator(t, op):
         ops.Sin: unary(sa.func.sin),
         ops.Sqrt: unary(sa.func.sqrt),
         ops.Tan: unary(sa.func.tan),
+        ops.Round: _round,
         # timestamp methods
         ops.TimestampNow: fixed_arity(sa.func.GETDATE, 0),
         ops.ExtractYear: _extract('year'),

ibis/backends/tests/test_numeric.py

@@ -102,7 +102,6 @@ def test_isnan_isinf(
             L(5.5).round(),
             6.0,
             id='round',
-            marks=pytest.mark.notimpl(["mssql"]),
         ),
         param(
             L(5.556).round(2),