test(redo): add some basic cast tests (#9483)

redo of #9461

ibis/backends/tests/test_generic.py

@@ -28,6 +28,7 @@
     OracleDatabaseError,
     PolarsSchemaError,
     PsycoPg2InternalError,
+    PsycoPg2SyntaxError,
     Py4JJavaError,
     PyDruidProgrammingError,
     PyODBCDataError,
@@ -1763,6 +1764,55 @@ def hash_256(col):
     backend.assert_series_equal(h1, h2)
 
 
+@pytest.mark.parametrize(
+    ("from_type", "to_type", "from_val", "expected"),
+    [
+        param("int", "float", 0, 0.0, id="int_to_float"),
+        param("float", "int", 0.0, 0, id="float_to_int"),
+        param("string", "int", "0", 0, id="string_to_int"),
+        param("string", "float", "0", 0.0, id="string_to_float"),
+        param(
+            "array<int>",
+            "array<string>",
+            [0, 1, 2],
+            ["0", "1", "2"],
+            marks=[
+                pytest.mark.notimpl(["pandas"], reason="casts to ['0']"),
+                pytest.mark.notimpl(["druid"], raises=PyDruidProgrammingError),
+                pytest.mark.notimpl(["oracle"], raises=OracleDatabaseError),
+                pytest.mark.never(
+                    ["exasol", "impala", "mssql", "mysql", "sqlite"],
+                    reason="backend doesn't support arrays",
+                ),
+            ],
+            id="array",
+        ),
+        param(
+            "struct<a: int, b: string>",
+            "struct<a: string, b: int>",
+            {"a": 0, "b": "1"},
+            {"a": "0", "b": 1},
+            marks=[
+                pytest.mark.notimpl(["flink"], raises=Py4JJavaError),
+                pytest.mark.notimpl(["druid"], raises=PyDruidProgrammingError),
+                pytest.mark.notimpl(["oracle"], raises=OracleDatabaseError),
+                pytest.mark.notimpl(["postgres"], raises=PsycoPg2SyntaxError),
+                pytest.mark.notimpl(["risingwave"], raises=PsycoPg2InternalError),
+                pytest.mark.never(
+                    ["datafusion", "exasol", "impala", "mssql", "mysql", "sqlite"],
+                    reason="backend doesn't support structs",
+                ),
+            ],
+            id="struct",
+        ),
+    ],
+)
+def test_cast(con, from_type, to_type, from_val, expected):
+    expr = ibis.literal(from_val, type=from_type).cast(to_type)
+    result = con.execute(expr)
+    assert result == expected
+
+
 @pytest.mark.notimpl(["pandas", "dask", "oracle", "sqlite"])
 @pytest.mark.parametrize(
     ("from_val", "to_type", "expected"),