import robin_sparkless as rs
def test_dataframe_alias_returns_dataframe() -> None:
spark = rs.SparkSession.builder().app_name("repro").get_or_create()
df = spark.createDataFrame([(1, 10)], ["id", "v"])
aliased = df.alias("t")
assert aliased is not None
rows = aliased.collect()
assert len(rows) == 1
assert rows[0]["id"] == 1
assert rows[0]["v"] == 10
def test_dataframe_alias_chaining() -> None:
spark = rs.SparkSession.builder().app_name("repro").get_or_create()
df = spark.createDataFrame([(1, 10), (2, 20)], ["id", "v"])
filtered = df.alias("t").filter(rs.col("id") > 1)
rows = filtered.collect()
assert len(rows) == 1
assert rows[0]["id"] == 2