#
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# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
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# the License.  You may obtain a copy of the License at
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#    http://www.apache.org/licenses/LICENSE-2.0
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import functools
import pydoc
import shutil
import tempfile
import unittest

from pyspark import SparkContext
from pyspark.sql import SparkSession, Column, Row
from pyspark.sql.functions import UserDefinedFunction, udf
from pyspark.sql.types import *
from pyspark.sql.utils import AnalysisException
from pyspark.testing.sqlutils import ReusedSQLTestCase, test_compiled, test_not_compiled_message
from pyspark.testing.utils import QuietTest


class UDFTests(ReusedSQLTestCase):

    def test_udf_with_callable(self):
        d = [Row(number=i, squared=i**2) for i in range(10)]
        rdd = self.sc.parallelize(d)
        data = self.spark.createDataFrame(rdd)

        class PlusFour:
            def __call__(self, col):
                if col is not None:
                    return col + 4

        call = PlusFour()
        pudf = UserDefinedFunction(call, LongType())
        res = data.select(pudf(data['number']).alias('plus_four'))
        self.assertEqual(res.agg({'plus_four': 'sum'}).collect()[0][0], 85)

    def test_udf_with_partial_function(self):
        d = [Row(number=i, squared=i**2) for i in range(10)]
        rdd = self.sc.parallelize(d)
        data = self.spark.createDataFrame(rdd)

        def some_func(col, param):
            if col is not None:
                return col + param

        pfunc = functools.partial(some_func, param=4)
        pudf = UserDefinedFunction(pfunc, LongType())
        res = data.select(pudf(data['number']).alias('plus_four'))
        self.assertEqual(res.agg({'plus_four': 'sum'}).collect()[0][0], 85)

    def test_udf(self):
        self.spark.catalog.registerFunction("twoArgs", lambda x, y: len(x) + y, IntegerType())
        [row] = self.spark.sql("SELECT twoArgs('test', 1)").collect()
        self.assertEqual(row[0], 5)

        # This is to check if a deprecated 'SQLContext.registerFunction' can call its alias.
        sqlContext = self.spark._wrapped
        sqlContext.registerFunction("oneArg", lambda x: len(x), IntegerType())
        [row] = sqlContext.sql("SELECT oneArg('test')").collect()
        self.assertEqual(row[0], 4)

    def test_udf2(self):
        with self.tempView("test"):
            self.spark.catalog.registerFunction("strlen", lambda string: len(string), IntegerType())
            self.spark.createDataFrame(self.sc.parallelize([Row(a="test")]))\
                .createOrReplaceTempView("test")
            [res] = self.spark.sql("SELECT strlen(a) FROM test WHERE strlen(a) > 1").collect()
            self.assertEqual(4, res[0])

    def test_udf3(self):
        two_args = self.spark.catalog.registerFunction(
            "twoArgs", UserDefinedFunction(lambda x, y: len(x) + y))
        self.assertEqual(two_args.deterministic, True)
        [row] = self.spark.sql("SELECT twoArgs('test', 1)").collect()
        self.assertEqual(row[0], u'5')

    def test_udf_registration_return_type_none(self):
        two_args = self.spark.catalog.registerFunction(
            "twoArgs", UserDefinedFunction(lambda x, y: len(x) + y, "integer"), None)
        self.assertEqual(two_args.deterministic, True)
        [row] = self.spark.sql("SELECT twoArgs('test', 1)").collect()
        self.assertEqual(row[0], 5)

    def test_udf_registration_return_type_not_none(self):
        with QuietTest(self.sc):
            with self.assertRaisesRegexp(TypeError, "Invalid returnType"):
                self.spark.catalog.registerFunction(
                    "f", UserDefinedFunction(lambda x, y: len(x) + y, StringType()), StringType())

    def test_nondeterministic_udf(self):
        # Test that nondeterministic UDFs are evaluated only once in chained UDF evaluations
        import random
        udf_random_col = udf(lambda: int(100 * random.random()), IntegerType()).asNondeterministic()
        self.assertEqual(udf_random_col.deterministic, False)
        df = self.spark.createDataFrame([Row(1)]).select(udf_random_col().alias('RAND'))
        udf_add_ten = udf(lambda rand: rand + 10, IntegerType())
        [row] = df.withColumn('RAND_PLUS_TEN', udf_add_ten('RAND')).collect()
        self.assertEqual(row[0] + 10, row[1])

    def test_nondeterministic_udf2(self):
        import random
        random_udf = udf(lambda: random.randint(6, 6), IntegerType()).asNondeterministic()
        self.assertEqual(random_udf.deterministic, False)
        random_udf1 = self.spark.catalog.registerFunction("randInt", random_udf)
        self.assertEqual(random_udf1.deterministic, False)
        [row] = self.spark.sql("SELECT randInt()").collect()
        self.assertEqual(row[0], 6)
        [row] = self.spark.range(1).select(random_udf1()).collect()
        self.assertEqual(row[0], 6)
        [row] = self.spark.range(1).select(random_udf()).collect()
        self.assertEqual(row[0], 6)
        # render_doc() reproduces the help() exception without printing output
        pydoc.render_doc(udf(lambda: random.randint(6, 6), IntegerType()))
        pydoc.render_doc(random_udf)
        pydoc.render_doc(random_udf1)
        pydoc.render_doc(udf(lambda x: x).asNondeterministic)

    def test_nondeterministic_udf3(self):
        # regression test for SPARK-23233
        f = udf(lambda x: x)
        # Here we cache the JVM UDF instance.
        self.spark.range(1).select(f("id"))
        # This should reset the cache to set the deterministic status correctly.
        f = f.asNondeterministic()
        # Check the deterministic status of udf.
        df = self.spark.range(1).select(f("id"))
        deterministic = df._jdf.logicalPlan().projectList().head().deterministic()
        self.assertFalse(deterministic)

    def test_nondeterministic_udf_in_aggregate(self):
        from pyspark.sql.functions import sum
        import random
        udf_random_col = udf(lambda: int(100 * random.random()), 'int').asNondeterministic()
        df = self.spark.range(10)

        with QuietTest(self.sc):
            with self.assertRaisesRegexp(AnalysisException, "nondeterministic"):
                df.groupby('id').agg(sum(udf_random_col())).collect()
            with self.assertRaisesRegexp(AnalysisException, "nondeterministic"):
                df.agg(sum(udf_random_col())).collect()

    def test_chained_udf(self):
        self.spark.catalog.registerFunction("double", lambda x: x + x, IntegerType())
        [row] = self.spark.sql("SELECT double(1)").collect()
        self.assertEqual(row[0], 2)
        [row] = self.spark.sql("SELECT double(double(1))").collect()
        self.assertEqual(row[0], 4)
        [row] = self.spark.sql("SELECT double(double(1) + 1)").collect()
        self.assertEqual(row[0], 6)

    def test_single_udf_with_repeated_argument(self):
        # regression test for SPARK-20685
        self.spark.catalog.registerFunction("add", lambda x, y: x + y, IntegerType())
        row = self.spark.sql("SELECT add(1, 1)").first()
        self.assertEqual(tuple(row), (2, ))

    def test_multiple_udfs(self):
        self.spark.catalog.registerFunction("double", lambda x: x * 2, IntegerType())
        [row] = self.spark.sql("SELECT double(1), double(2)").collect()
        self.assertEqual(tuple(row), (2, 4))
        [row] = self.spark.sql("SELECT double(double(1)), double(double(2) + 2)").collect()
        self.assertEqual(tuple(row), (4, 12))
        self.spark.catalog.registerFunction("add", lambda x, y: x + y, IntegerType())
        [row] = self.spark.sql("SELECT double(add(1, 2)), add(double(2), 1)").collect()
        self.assertEqual(tuple(row), (6, 5))

    def test_udf_in_filter_on_top_of_outer_join(self):
        left = self.spark.createDataFrame([Row(a=1)])
        right = self.spark.createDataFrame([Row(a=1)])
        df = left.join(right, on='a', how='left_outer')
        df = df.withColumn('b', udf(lambda x: 'x')(df.a))
        self.assertEqual(df.filter('b = "x"').collect(), [Row(a=1, b='x')])

    def test_udf_in_filter_on_top_of_join(self):
        # regression test for SPARK-18589
        left = self.spark.createDataFrame([Row(a=1)])
        right = self.spark.createDataFrame([Row(b=1)])
        f = udf(lambda a, b: a == b, BooleanType())
        df = left.crossJoin(right).filter(f("a", "b"))
        self.assertEqual(df.collect(), [Row(a=1, b=1)])

    def test_udf_in_join_condition(self):
        # regression test for SPARK-25314
        left = self.spark.createDataFrame([Row(a=1)])
        right = self.spark.createDataFrame([Row(b=1)])
        f = udf(lambda a, b: a == b, BooleanType())
        df = left.join(right, f("a", "b"))
        with self.assertRaisesRegexp(AnalysisException, 'Detected implicit cartesian product'):
            df.collect()
        with self.sql_conf({"spark.sql.crossJoin.enabled": True}):
            self.assertEqual(df.collect(), [Row(a=1, b=1)])

    def test_udf_in_left_outer_join_condition(self):
        # regression test for SPARK-26147
        from pyspark.sql.functions import col
        left = self.spark.createDataFrame([Row(a=1)])
        right = self.spark.createDataFrame([Row(b=1)])
        f = udf(lambda a: str(a), StringType())
        # The join condition can't be pushed down, as it refers to attributes from both sides.
        # The Python UDF only refer to attributes from one side, so it's evaluable.
        df = left.join(right, f("a") == col("b").cast("string"), how="left_outer")
        with self.sql_conf({"spark.sql.crossJoin.enabled": True}):
            self.assertEqual(df.collect(), [Row(a=1, b=1)])

    def test_udf_and_common_filter_in_join_condition(self):
        # regression test for SPARK-25314
        # test the complex scenario with both udf and common filter
        left = self.spark.createDataFrame([Row(a=1, a1=1, a2=1), Row(a=2, a1=2, a2=2)])
        right = self.spark.createDataFrame([Row(b=1, b1=1, b2=1), Row(b=1, b1=3, b2=1)])
        f = udf(lambda a, b: a == b, BooleanType())
        df = left.join(right, [f("a", "b"), left.a1 == right.b1])
        # do not need spark.sql.crossJoin.enabled=true for udf is not the only join condition.
        self.assertEqual(df.collect(), [Row(a=1, a1=1, a2=1, b=1, b1=1, b2=1)])

    def test_udf_not_supported_in_join_condition(self):
        # regression test for SPARK-25314
        # test python udf is not supported in join type except inner join.
        left = self.spark.createDataFrame([Row(a=1, a1=1, a2=1), Row(a=2, a1=2, a2=2)])
        right = self.spark.createDataFrame([Row(b=1, b1=1, b2=1), Row(b=1, b1=3, b2=1)])
        f = udf(lambda a, b: a == b, BooleanType())

        def runWithJoinType(join_type, type_string):
            with self.assertRaisesRegexp(
                    AnalysisException,
                    'Using PythonUDF.*%s is not supported.' % type_string):
                left.join(right, [f("a", "b"), left.a1 == right.b1], join_type).collect()
        runWithJoinType("full", "FullOuter")
        runWithJoinType("left", "LeftOuter")
        runWithJoinType("right", "RightOuter")
        runWithJoinType("leftanti", "LeftAnti")
        runWithJoinType("leftsemi", "LeftSemi")

    def test_udf_without_arguments(self):
        self.spark.catalog.registerFunction("foo", lambda: "bar")
        [row] = self.spark.sql("SELECT foo()").collect()
        self.assertEqual(row[0], "bar")

    def test_udf_with_array_type(self):
        with self.tempView("test"):
            d = [Row(l=list(range(3)), d={"key": list(range(5))})]
            rdd = self.sc.parallelize(d)
            self.spark.createDataFrame(rdd).createOrReplaceTempView("test")
            self.spark.catalog.registerFunction(
                "copylist", lambda l: list(l), ArrayType(IntegerType()))
            self.spark.catalog.registerFunction("maplen", lambda d: len(d), IntegerType())
            [(l1, l2)] = self.spark.sql("select copylist(l), maplen(d) from test").collect()
            self.assertEqual(list(range(3)), l1)
            self.assertEqual(1, l2)

    def test_broadcast_in_udf(self):
        bar = {"a": "aa", "b": "bb", "c": "abc"}
        foo = self.sc.broadcast(bar)
        self.spark.catalog.registerFunction("MYUDF", lambda x: foo.value[x] if x else '')
        [res] = self.spark.sql("SELECT MYUDF('c')").collect()
        self.assertEqual("abc", res[0])
        [res] = self.spark.sql("SELECT MYUDF('')").collect()
        self.assertEqual("", res[0])

    def test_udf_with_filter_function(self):
        df = self.spark.createDataFrame([(1, "1"), (2, "2"), (1, "2"), (1, "2")], ["key", "value"])
        from pyspark.sql.functions import col
        from pyspark.sql.types import BooleanType

        my_filter = udf(lambda a: a < 2, BooleanType())
        sel = df.select(col("key"), col("value")).filter((my_filter(col("key"))) & (df.value < "2"))
        self.assertEqual(sel.collect(), [Row(key=1, value='1')])

    def test_udf_with_aggregate_function(self):
        df = self.spark.createDataFrame([(1, "1"), (2, "2"), (1, "2"), (1, "2")], ["key", "value"])
        from pyspark.sql.functions import col, sum
        from pyspark.sql.types import BooleanType

        my_filter = udf(lambda a: a == 1, BooleanType())
        sel = df.select(col("key")).distinct().filter(my_filter(col("key")))
        self.assertEqual(sel.collect(), [Row(key=1)])

        my_copy = udf(lambda x: x, IntegerType())
        my_add = udf(lambda a, b: int(a + b), IntegerType())
        my_strlen = udf(lambda x: len(x), IntegerType())
        sel = df.groupBy(my_copy(col("key")).alias("k"))\
            .agg(sum(my_strlen(col("value"))).alias("s"))\
            .select(my_add(col("k"), col("s")).alias("t"))
        self.assertEqual(sel.collect(), [Row(t=4), Row(t=3)])

    def test_udf_in_generate(self):
        from pyspark.sql.functions import explode
        df = self.spark.range(5)
        f = udf(lambda x: list(range(x)), ArrayType(LongType()))
        row = df.select(explode(f(*df))).groupBy().sum().first()
        self.assertEqual(row[0], 10)

        df = self.spark.range(3)
        res = df.select("id", explode(f(df.id))).collect()
        self.assertEqual(res[0][0], 1)
        self.assertEqual(res[0][1], 0)
        self.assertEqual(res[1][0], 2)
        self.assertEqual(res[1][1], 0)
        self.assertEqual(res[2][0], 2)
        self.assertEqual(res[2][1], 1)

        range_udf = udf(lambda value: list(range(value - 1, value + 1)), ArrayType(IntegerType()))
        res = df.select("id", explode(range_udf(df.id))).collect()
        self.assertEqual(res[0][0], 0)
        self.assertEqual(res[0][1], -1)
        self.assertEqual(res[1][0], 0)
        self.assertEqual(res[1][1], 0)
        self.assertEqual(res[2][0], 1)
        self.assertEqual(res[2][1], 0)
        self.assertEqual(res[3][0], 1)
        self.assertEqual(res[3][1], 1)

    def test_udf_with_order_by_and_limit(self):
        my_copy = udf(lambda x: x, IntegerType())
        df = self.spark.range(10).orderBy("id")
        res = df.select(df.id, my_copy(df.id).alias("copy")).limit(1)
        res.explain(True)
        self.assertEqual(res.collect(), [Row(id=0, copy=0)])

    def test_udf_registration_returns_udf(self):
        df = self.spark.range(10)
        add_three = self.spark.udf.register("add_three", lambda x: x + 3, IntegerType())

        self.assertListEqual(
            df.selectExpr("add_three(id) AS plus_three").collect(),
            df.select(add_three("id").alias("plus_three")).collect()
        )

        # This is to check if a 'SQLContext.udf' can call its alias.
        sqlContext = self.spark._wrapped
        add_four = sqlContext.udf.register("add_four", lambda x: x + 4, IntegerType())

        self.assertListEqual(
            df.selectExpr("add_four(id) AS plus_four").collect(),
            df.select(add_four("id").alias("plus_four")).collect()
        )

    def test_non_existed_udf(self):
        spark = self.spark
        self.assertRaisesRegexp(AnalysisException, "Can not load class non_existed_udf",
                                lambda: spark.udf.registerJavaFunction("udf1", "non_existed_udf"))

        # This is to check if a deprecated 'SQLContext.registerJavaFunction' can call its alias.
        sqlContext = spark._wrapped
        self.assertRaisesRegexp(AnalysisException, "Can not load class non_existed_udf",
                                lambda: sqlContext.registerJavaFunction("udf1", "non_existed_udf"))

    def test_non_existed_udaf(self):
        spark = self.spark
        self.assertRaisesRegexp(AnalysisException, "Can not load class non_existed_udaf",
                                lambda: spark.udf.registerJavaUDAF("udaf1", "non_existed_udaf"))

    def test_udf_with_input_file_name(self):
        from pyspark.sql.functions import input_file_name
        sourceFile = udf(lambda path: path, StringType())
        filePath = "python/test_support/sql/people1.json"
        row = self.spark.read.json(filePath).select(sourceFile(input_file_name())).first()
        self.assertTrue(row[0].find("people1.json") != -1)

    def test_udf_with_input_file_name_for_hadooprdd(self):
        from pyspark.sql.functions import input_file_name

        def filename(path):
            return path

        sameText = udf(filename, StringType())

        rdd = self.sc.textFile('python/test_support/sql/people.json')
        df = self.spark.read.json(rdd).select(input_file_name().alias('file'))
        row = df.select(sameText(df['file'])).first()
        self.assertTrue(row[0].find("people.json") != -1)

        rdd2 = self.sc.newAPIHadoopFile(
            'python/test_support/sql/people.json',
            'org.apache.hadoop.mapreduce.lib.input.TextInputFormat',
            'org.apache.hadoop.io.LongWritable',
            'org.apache.hadoop.io.Text')

        df2 = self.spark.read.json(rdd2).select(input_file_name().alias('file'))
        row2 = df2.select(sameText(df2['file'])).first()
        self.assertTrue(row2[0].find("people.json") != -1)

    def test_udf_defers_judf_initialization(self):
        # This is separate of  UDFInitializationTests
        # to avoid context initialization
        # when udf is called
        f = UserDefinedFunction(lambda x: x, StringType())

        self.assertIsNone(
            f._judf_placeholder,
            "judf should not be initialized before the first call."
        )

        self.assertIsInstance(f("foo"), Column, "UDF call should return a Column.")

        self.assertIsNotNone(
            f._judf_placeholder,
            "judf should be initialized after UDF has been called."
        )

    def test_udf_with_string_return_type(self):
        add_one = UserDefinedFunction(lambda x: x + 1, "integer")
        make_pair = UserDefinedFunction(lambda x: (-x, x), "struct<x:integer,y:integer>")
        make_array = UserDefinedFunction(
            lambda x: [float(x) for x in range(x, x + 3)], "array<double>")

        expected = (2, Row(x=-1, y=1), [1.0, 2.0, 3.0])
        actual = (self.spark.range(1, 2).toDF("x")
                  .select(add_one("x"), make_pair("x"), make_array("x"))
                  .first())

        self.assertTupleEqual(expected, actual)

    def test_udf_shouldnt_accept_noncallable_object(self):
        non_callable = None
        self.assertRaises(TypeError, UserDefinedFunction, non_callable, StringType())

    def test_udf_with_decorator(self):
        from pyspark.sql.functions import lit
        from pyspark.sql.types import IntegerType, DoubleType

        @udf(IntegerType())
        def add_one(x):
            if x is not None:
                return x + 1

        @udf(returnType=DoubleType())
        def add_two(x):
            if x is not None:
                return float(x + 2)

        @udf
        def to_upper(x):
            if x is not None:
                return x.upper()

        @udf()
        def to_lower(x):
            if x is not None:
                return x.lower()

        @udf
        def substr(x, start, end):
            if x is not None:
                return x[start:end]

        @udf("long")
        def trunc(x):
            return int(x)

        @udf(returnType="double")
        def as_double(x):
            return float(x)

        df = (
            self.spark
                .createDataFrame(
                    [(1, "Foo", "foobar", 3.0)], ("one", "Foo", "foobar", "float"))
                .select(
                    add_one("one"), add_two("one"),
                    to_upper("Foo"), to_lower("Foo"),
                    substr("foobar", lit(0), lit(3)),
                    trunc("float"), as_double("one")))

        self.assertListEqual(
            [tpe for _, tpe in df.dtypes],
            ["int", "double", "string", "string", "string", "bigint", "double"]
        )

        self.assertListEqual(
            list(df.first()),
            [2, 3.0, "FOO", "foo", "foo", 3, 1.0]
        )

    def test_udf_wrapper(self):
        from pyspark.sql.types import IntegerType

        def f(x):
            """Identity"""
            return x

        return_type = IntegerType()
        f_ = udf(f, return_type)

        self.assertTrue(f.__doc__ in f_.__doc__)
        self.assertEqual(f, f_.func)
        self.assertEqual(return_type, f_.returnType)

        class F(object):
            """Identity"""
            def __call__(self, x):
                return x

        f = F()
        return_type = IntegerType()
        f_ = udf(f, return_type)

        self.assertTrue(f.__doc__ in f_.__doc__)
        self.assertEqual(f, f_.func)
        self.assertEqual(return_type, f_.returnType)

        f = functools.partial(f, x=1)
        return_type = IntegerType()
        f_ = udf(f, return_type)

        self.assertTrue(f.__doc__ in f_.__doc__)
        self.assertEqual(f, f_.func)
        self.assertEqual(return_type, f_.returnType)

    def test_nonparam_udf_with_aggregate(self):
        import pyspark.sql.functions as f

        df = self.spark.createDataFrame([(1, 2), (1, 2)])
        f_udf = f.udf(lambda: "const_str")
        rows = df.distinct().withColumn("a", f_udf()).collect()
        self.assertEqual(rows, [Row(_1=1, _2=2, a=u'const_str')])

    # SPARK-24721
    @unittest.skipIf(not test_compiled, test_not_compiled_message)
    def test_datasource_with_udf(self):
        from pyspark.sql.functions import lit, col

        path = tempfile.mkdtemp()
        shutil.rmtree(path)

        try:
            self.spark.range(1).write.mode("overwrite").format('csv').save(path)
            filesource_df = self.spark.read.option('inferSchema', True).csv(path).toDF('i')
            datasource_df = self.spark.read \
                .format("org.apache.spark.sql.sources.SimpleScanSource") \
                .option('from', 0).option('to', 1).load().toDF('i')
            datasource_v2_df = self.spark.read \
                .format("org.apache.spark.sql.sources.v2.SimpleDataSourceV2") \
                .load().toDF('i', 'j')

            c1 = udf(lambda x: x + 1, 'int')(lit(1))
            c2 = udf(lambda x: x + 1, 'int')(col('i'))

            f1 = udf(lambda x: False, 'boolean')(lit(1))
            f2 = udf(lambda x: False, 'boolean')(col('i'))

            for df in [filesource_df, datasource_df, datasource_v2_df]:
                result = df.withColumn('c', c1)
                expected = df.withColumn('c', lit(2))
                self.assertEquals(expected.collect(), result.collect())

            for df in [filesource_df, datasource_df, datasource_v2_df]:
                result = df.withColumn('c', c2)
                expected = df.withColumn('c', col('i') + 1)
                self.assertEquals(expected.collect(), result.collect())

            for df in [filesource_df, datasource_df, datasource_v2_df]:
                for f in [f1, f2]:
                    result = df.filter(f)
                    self.assertEquals(0, result.count())
        finally:
            shutil.rmtree(path)

    # SPARK-25591
    def test_same_accumulator_in_udfs(self):
        data_schema = StructType([StructField("a", IntegerType(), True),
                                  StructField("b", IntegerType(), True)])
        data = self.spark.createDataFrame([[1, 2]], schema=data_schema)

        test_accum = self.sc.accumulator(0)

        def first_udf(x):
            test_accum.add(1)
            return x

        def second_udf(x):
            test_accum.add(100)
            return x

        func_udf = udf(first_udf, IntegerType())
        func_udf2 = udf(second_udf, IntegerType())
        data = data.withColumn("out1", func_udf(data["a"]))
        data = data.withColumn("out2", func_udf2(data["b"]))
        data.collect()
        self.assertEqual(test_accum.value, 101)

    # SPARK-26293
    def test_udf_in_subquery(self):
        f = udf(lambda x: x, "long")
        with self.tempView("v"):
            self.spark.range(1).filter(f("id") >= 0).createTempView("v")
            sql = self.spark.sql
            result = sql("select i from values(0L) as data(i) where i in (select id from v)")
            self.assertEqual(result.collect(), [Row(i=0)])

    def test_udf_globals_not_overwritten(self):
        @udf('string')
        def f():
            assert "itertools" not in str(map)

        self.spark.range(1).select(f()).collect()


class UDFInitializationTests(unittest.TestCase):
    def tearDown(self):
        if SparkSession._instantiatedSession is not None:
            SparkSession._instantiatedSession.stop()

        if SparkContext._active_spark_context is not None:
            SparkContext._active_spark_context.stop()

    def test_udf_init_shouldnt_initialize_context(self):
        UserDefinedFunction(lambda x: x, StringType())

        self.assertIsNone(
            SparkContext._active_spark_context,
            "SparkContext shouldn't be initialized when UserDefinedFunction is created."
        )
        self.assertIsNone(
            SparkSession._instantiatedSession,
            "SparkSession shouldn't be initialized when UserDefinedFunction is created."
        )


if __name__ == "__main__":
    from pyspark.sql.tests.test_udf import *

    try:
        import xmlrunner
        testRunner = xmlrunner.XMLTestRunner(output='target/test-reports')
    except ImportError:
        testRunner = None
    unittest.main(testRunner=testRunner, verbosity=2)