## What changes were proposed in this pull request?
I propose to add a clear statement for functions like `collect_list()` about non-deterministic behavior of such functions. The behavior must be taken into account by user while creating and running queries.
Author: Maxim Gekk <maxim.gekk@databricks.com>
Closes#21228 from MaxGekk/deterministic-comments.
## What changes were proposed in this pull request?
More close to Scala API behavior when can't parse input by throwing exception. Add tests.
## How was this patch tested?
Added tests.
Author: Liang-Chi Hsieh <viirya@gmail.com>
Closes#21211 from viirya/SPARK-24131-followup.
## What changes were proposed in this pull request?
Change FPGrowth from private to private[spark]. If no numPartitions is specified, then default value -1 is used. But -1 is only valid in the construction function of FPGrowth, but not in setNumPartitions. So I make this change and use the constructor directly rather than using set method.
## How was this patch tested?
Unit test is added
Author: Jeff Zhang <zjffdu@apache.org>
Closes#13493 from zjffdu/SPARK-15750.
## What changes were proposed in this pull request?
The PR add the `slice` function. The behavior of the function is based on Presto's one.
The function slices an array according to the requested start index and length.
## How was this patch tested?
added UTs
Author: Marco Gaido <marcogaido91@gmail.com>
Closes#21040 from mgaido91/SPARK-23930.
## What changes were proposed in this pull request?
The PR adds the SQL function `array_sort`. The behavior of the function is based on Presto's one.
The function sorts the input array in ascending order. The elements of the input array must be orderable. Null elements will be placed at the end of the returned array.
## How was this patch tested?
Added UTs
Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Closes#21021 from kiszk/SPARK-23921.
This avoids polluting and leaving garbage behind in /tmp, and allows the
usual build tools to clean up any leftover files.
Author: Marcelo Vanzin <vanzin@cloudera.com>
Closes#21198 from vanzin/SPARK-24126.
## What changes were proposed in this pull request?
We need to determine Spark major and minor versions in PySpark. We can add a `majorMinorVersion` API to PySpark which is similar to the Scala API in `VersionUtils.majorMinorVersion`.
## How was this patch tested?
Added tests.
Author: Liang-Chi Hsieh <viirya@gmail.com>
Closes#21203 from viirya/SPARK-24131.
## What changes were proposed in this pull request?
When `PyArrow` or `Pandas` are not available, the corresponding PySpark tests are skipped automatically. Currently, PySpark tests fail when we are not using `-Phive`. This PR aims to skip Hive related PySpark tests when `-Phive` is not given.
**BEFORE**
```bash
$ build/mvn -DskipTests clean package
$ python/run-tests.py --python-executables python2.7 --modules pyspark-sql
File "/Users/dongjoon/spark/python/pyspark/sql/readwriter.py", line 295, in pyspark.sql.readwriter.DataFrameReader.table
...
IllegalArgumentException: u"Error while instantiating 'org.apache.spark.sql.hive.HiveExternalCatalog':"
**********************************************************************
1 of 3 in pyspark.sql.readwriter.DataFrameReader.table
***Test Failed*** 1 failures.
```
**AFTER**
```bash
$ build/mvn -DskipTests clean package
$ python/run-tests.py --python-executables python2.7 --modules pyspark-sql
...
Tests passed in 138 seconds
Skipped tests in pyspark.sql.tests with python2.7:
...
test_hivecontext (pyspark.sql.tests.HiveSparkSubmitTests) ... skipped 'Hive is not available.'
```
## How was this patch tested?
This is a test-only change. First, this should pass the Jenkins. Then, manually do the following.
```bash
build/mvn -DskipTests clean package
python/run-tests.py --python-executables python2.7 --modules pyspark-sql
```
Author: Dongjoon Hyun <dongjoon@apache.org>
Closes#21141 from dongjoon-hyun/SPARK-23853.
## What changes were proposed in this pull request?
I propose to support the `samplingRatio` option for schema inferring of CSV datasource similar to the same option of JSON datasource:
b14993e1fc/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/json/JSONOptions.scala (L49-L50)
## How was this patch tested?
Added 2 tests for json and 2 tests for csv datasources. The tests checks that only subset of input dataset is used for schema inferring.
Author: Maxim Gekk <maxim.gekk@databricks.com>
Author: Maxim Gekk <max.gekk@gmail.com>
Closes#20959 from MaxGekk/csv-sampling.
## What changes were proposed in this pull request?
I propose new option for JSON datasource which allows to specify encoding (charset) of input and output files. Here is an example of using of the option:
```
spark.read.schema(schema)
.option("multiline", "true")
.option("encoding", "UTF-16LE")
.json(fileName)
```
If the option is not specified, charset auto-detection mechanism is used by default.
The option can be used for saving datasets to jsons. Currently Spark is able to save datasets into json files in `UTF-8` charset only. The changes allow to save data in any supported charset. Here is the approximate list of supported charsets by Oracle Java SE: https://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html . An user can specify the charset of output jsons via the charset option like `.option("charset", "UTF-16BE")`. By default the output charset is still `UTF-8` to keep backward compatibility.
The solution has the following restrictions for per-line mode (`multiline = false`):
- If charset is different from UTF-8, the lineSep option must be specified. The option required because Hadoop LineReader cannot detect the line separator correctly. Here is the ticket for solving the issue: https://issues.apache.org/jira/browse/SPARK-23725
- Encoding with [BOM](https://en.wikipedia.org/wiki/Byte_order_mark) are not supported. For example, the `UTF-16` and `UTF-32` encodings are blacklisted. The problem can be solved by https://github.com/MaxGekk/spark-1/pull/2
## How was this patch tested?
I added the following tests:
- reads an json file in `UTF-16LE` encoding with BOM in `multiline` mode
- read json file by using charset auto detection (`UTF-32BE` with BOM)
- read json file using of user's charset (`UTF-16LE`)
- saving in `UTF-32BE` and read the result by standard library (not by Spark)
- checking that default charset is `UTF-8`
- handling wrong (unsupported) charset
Author: Maxim Gekk <maxim.gekk@databricks.com>
Author: Maxim Gekk <max.gekk@gmail.com>
Closes#20937 from MaxGekk/json-encoding-line-sep.
## What changes were proposed in this pull request?
This PR proposes to remove duplicated dependency checking logics and also print out skipped tests from unittests.
For example, as below:
```
Skipped tests in pyspark.sql.tests with pypy:
test_createDataFrame_column_name_encoding (pyspark.sql.tests.ArrowTests) ... skipped 'Pandas >= 0.19.2 must be installed; however, it was not found.'
test_createDataFrame_does_not_modify_input (pyspark.sql.tests.ArrowTests) ... skipped 'Pandas >= 0.19.2 must be installed; however, it was not found.'
...
Skipped tests in pyspark.sql.tests with python3:
test_createDataFrame_column_name_encoding (pyspark.sql.tests.ArrowTests) ... skipped 'PyArrow >= 0.8.0 must be installed; however, it was not found.'
test_createDataFrame_does_not_modify_input (pyspark.sql.tests.ArrowTests) ... skipped 'PyArrow >= 0.8.0 must be installed; however, it was not found.'
...
```
Currently, it's not printed out in the console. I think we should better print out skipped tests in the console.
## How was this patch tested?
Manually tested. Also, fortunately, Jenkins has good environment to test the skipped output.
Author: hyukjinkwon <gurwls223@apache.org>
Closes#21107 from HyukjinKwon/skipped-tests-print.
## What changes were proposed in this pull request?
Print out the data type in the AssertionError message to make it more meaningful.
## How was this patch tested?
I manually tested the changed code on my local, but didn't add any test.
Author: Huaxin Gao <huaxing@us.ibm.com>
Closes#21159 from huaxingao/spark-24057.
## What changes were proposed in this pull request?
The PR adds the SQL function `array_join`. The behavior of the function is based on Presto's one.
The function accepts an `array` of `string` which is to be joined, a `string` which is the delimiter to use between the items of the first argument and optionally a `string` which is used to replace `null` values.
## How was this patch tested?
added UTs
Author: Marco Gaido <marcogaido91@gmail.com>
Closes#21011 from mgaido91/SPARK-23916.
## What changes were proposed in this pull request?
HIVE-15511 introduced the `roundOff` flag in order to disable the rounding to 8 digits which is performed in `months_between`. Since this can be a computational intensive operation, skipping it may improve performances when the rounding is not needed.
## How was this patch tested?
modified existing UT
Author: Marco Gaido <marcogaido91@gmail.com>
Closes#21008 from mgaido91/SPARK-23902.
## What changes were proposed in this pull request?
Added the `samplingRatio` option to the `json()` method of PySpark DataFrame Reader. Improving existing tests for Scala API according to review of the PR: https://github.com/apache/spark/pull/20959
## How was this patch tested?
Added new test for PySpark, updated 2 existing tests according to reviews of https://github.com/apache/spark/pull/20959 and added new negative test
Author: Maxim Gekk <maxim.gekk@databricks.com>
Closes#21056 from MaxGekk/json-sampling.
## What changes were proposed in this pull request?
The PR adds the SQL function `element_at`. The behavior of the function is based on Presto's one.
This function returns element of array at given index in value if column is array, or returns value for the given key in value if column is map.
## How was this patch tested?
Added UTs
Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Closes#21053 from kiszk/SPARK-23924.
## What changes were proposed in this pull request?
The PR adds the SQL function `array_position`. The behavior of the function is based on Presto's one.
The function returns the position of the first occurrence of the element in array x (or 0 if not found) using 1-based index as BigInt.
## How was this patch tested?
Added UTs
Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Closes#21037 from kiszk/SPARK-23919.
## What changes were proposed in this pull request?
The `StreamingListener` in PySpark side seems to be lack of `onStreamingStarted` method. This patch adds it and a test for it.
This patch also includes a trivial doc improvement for `createDirectStream`.
Original PR is #21057.
## How was this patch tested?
Added test.
Author: Liang-Chi Hsieh <viirya@gmail.com>
Closes#21098 from viirya/SPARK-24014.
## What changes were proposed in this pull request?
Python API for DataFrame-based multivariate summarizer.
## How was this patch tested?
doctest added.
Author: WeichenXu <weichen.xu@databricks.com>
Closes#20695 from WeichenXu123/py_summarizer.
## What changes were proposed in this pull request?
The PR adds the SQL function `array_min`. It takes an array as argument and returns the minimum value in it.
## How was this patch tested?
added UTs
Author: Marco Gaido <marcogaido91@gmail.com>
Closes#21025 from mgaido91/SPARK-23918.
## What changes were proposed in this pull request?
Add python API for collecting sub-models during CrossValidator/TrainValidationSplit fitting.
## How was this patch tested?
UT added.
Author: WeichenXu <weichen.xu@databricks.com>
Closes#19627 from WeichenXu123/expose-model-list-py.
## What changes were proposed in this pull request?
The PR adds the SQL function `array_max`. It takes an array as argument and returns the maximum value in it.
## How was this patch tested?
added UTs
Author: Marco Gaido <marcogaido91@gmail.com>
Closes#21024 from mgaido91/SPARK-23917.
## What changes were proposed in this pull request?
This PR proposes to add `collect` to a query executor as an action.
Seems `collect` / `collect` with Arrow are not recognised via `QueryExecutionListener` as an action. For example, if we have a custom listener as below:
```scala
package org.apache.spark.sql
import org.apache.spark.internal.Logging
import org.apache.spark.sql.execution.QueryExecution
import org.apache.spark.sql.util.QueryExecutionListener
class TestQueryExecutionListener extends QueryExecutionListener with Logging {
override def onSuccess(funcName: String, qe: QueryExecution, durationNs: Long): Unit = {
logError("Look at me! I'm 'onSuccess'")
}
override def onFailure(funcName: String, qe: QueryExecution, exception: Exception): Unit = { }
}
```
and set `spark.sql.queryExecutionListeners` to `org.apache.spark.sql.TestQueryExecutionListener`
Other operations in PySpark or Scala side seems fine:
```python
>>> sql("SELECT * FROM range(1)").show()
```
```
18/04/09 17:02:04 ERROR TestQueryExecutionListener: Look at me! I'm 'onSuccess'
+---+
| id|
+---+
| 0|
+---+
```
```scala
scala> sql("SELECT * FROM range(1)").collect()
```
```
18/04/09 16:58:41 ERROR TestQueryExecutionListener: Look at me! I'm 'onSuccess'
res1: Array[org.apache.spark.sql.Row] = Array([0])
```
but ..
**Before**
```python
>>> sql("SELECT * FROM range(1)").collect()
```
```
[Row(id=0)]
```
```python
>>> spark.conf.set("spark.sql.execution.arrow.enabled", "true")
>>> sql("SELECT * FROM range(1)").toPandas()
```
```
id
0 0
```
**After**
```python
>>> sql("SELECT * FROM range(1)").collect()
```
```
18/04/09 16:57:58 ERROR TestQueryExecutionListener: Look at me! I'm 'onSuccess'
[Row(id=0)]
```
```python
>>> spark.conf.set("spark.sql.execution.arrow.enabled", "true")
>>> sql("SELECT * FROM range(1)").toPandas()
```
```
18/04/09 17:53:26 ERROR TestQueryExecutionListener: Look at me! I'm 'onSuccess'
id
0 0
```
## How was this patch tested?
I have manually tested as described above and unit test was added.
Author: hyukjinkwon <gurwls223@apache.org>
Closes#21007 from HyukjinKwon/SPARK-23942.
MultilayerPerceptronClassifier had 4 occurrences
## What changes were proposed in this pull request?
(Please fill in changes proposed in this fix)
## How was this patch tested?
(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)
(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)
Please review http://spark.apache.org/contributing.html before opening a pull request.
Author: JBauerKogentix <37910022+JBauerKogentix@users.noreply.github.com>
Closes#21030 from JBauerKogentix/patch-1.
## What changes were proposed in this pull request?
There was a mistake in `tests.py` missing `assertEquals`.
## How was this patch tested?
Fixed tests.
Author: hyukjinkwon <gurwls223@apache.org>
Closes#21035 from HyukjinKwon/SPARK-23847.
## What changes were proposed in this pull request?
add python api for VectorAssembler handleInvalid
## How was this patch tested?
Add doctest
Author: Huaxin Gao <huaxing@us.ibm.com>
Closes#21003 from huaxingao/spark-23871.
## What changes were proposed in this pull request?
Kolmogorov-Smirnoff test Python API in `pyspark.ml`
**Note** API with `CDF` is a little difficult to support in python. We can add it in following PR.
## How was this patch tested?
doctest
Author: WeichenXu <weichen.xu@databricks.com>
Closes#20904 from WeichenXu123/ks-test-py.
## What changes were proposed in this pull request?
Column.scala and Functions.scala have asc_nulls_first, asc_nulls_last, desc_nulls_first and desc_nulls_last. Add the corresponding python APIs in column.py and functions.py
## How was this patch tested?
Add doctest
Author: Huaxin Gao <huaxing@us.ibm.com>
Closes#20962 from huaxingao/spark-23847.
## What changes were proposed in this pull request?
The Scala StringIndexerModel has an alternate constructor that will create the model from an array of label strings. Add the corresponding Python API:
model = StringIndexerModel.from_labels(["a", "b", "c"])
## How was this patch tested?
Add doctest and unit test.
Author: Huaxin Gao <huaxing@us.ibm.com>
Closes#20968 from huaxingao/spark-23828.
## What changes were proposed in this pull request?
Add docstring to clarify default window frame boundaries with and without orderBy clause
## How was this patch tested?
Manually generate doc and check.
Author: Li Jin <ice.xelloss@gmail.com>
Closes#20978 from icexelloss/SPARK-23861-window-doc.
## What changes were proposed in this pull request?
Easy fix in the documentation.
## How was this patch tested?
N/A
Closes#20948
Author: Daniel Sakuma <dsakuma@gmail.com>
Closes#20928 from dsakuma/fix_typo_configuration_docs.
## What changes were proposed in this pull request?
Adding test for default params for `CountVectorizerModel` constructed from vocabulary. This required that the param `maxDF` be added, which was done in SPARK-23615.
## How was this patch tested?
Added an explicit test for CountVectorizerModel in DefaultValuesTests.
Author: Bryan Cutler <cutlerb@gmail.com>
Closes#20942 from BryanCutler/pyspark-CountVectorizerModel-default-param-test-SPARK-15009.
## What changes were proposed in this pull request?
This PR proposes to add lineSep option for a configurable line separator in text datasource.
It supports this option by using `LineRecordReader`'s functionality with passing it to the constructor.
The approach is similar with https://github.com/apache/spark/pull/20727; however, one main difference is, it uses text datasource's `lineSep` option to parse line by line in JSON's schema inference.
## How was this patch tested?
Manually tested and unit tests were added.
Author: hyukjinkwon <gurwls223@apache.org>
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#20877 from HyukjinKwon/linesep-json.
## What changes were proposed in this pull request?
When using Arrow for createDataFrame or toPandas and an error is encountered with fallback disabled, this will raise the same type of error instead of a RuntimeError. This change also allows for the traceback of the error to be retained and prevents the accidental chaining of exceptions with Python 3.
## How was this patch tested?
Updated existing tests to verify error type.
Author: Bryan Cutler <cutlerb@gmail.com>
Closes#20839 from BryanCutler/arrow-raise-same-error-SPARK-23699.
## What changes were proposed in this pull request?
Adding r2adj in LinearRegressionSummary for Python API.
## How was this patch tested?
Added unit tests to exercise the api calls for the summary classes in tests.py.
Author: Kevin Yu <qyu@us.ibm.com>
Closes#20842 from kevinyu98/spark-23162.
## What changes were proposed in this pull request?
Add documentation about the limitations of `pandas_udf` with keyword arguments and related concepts, like `functools.partial` fn objects.
NOTE: intermediate commits on this PR show some of the steps that can be taken to fix some (but not all) of these pain points.
### Survey of problems we face today:
(Initialize) Note: python 3.6 and spark 2.4snapshot.
```
from pyspark.sql import SparkSession
import inspect, functools
from pyspark.sql.functions import pandas_udf, PandasUDFType, col, lit, udf
spark = SparkSession.builder.getOrCreate()
print(spark.version)
df = spark.range(1,6).withColumn('b', col('id') * 2)
def ok(a,b): return a+b
```
Using a keyword argument at the call site `b=...` (and yes, *full* stack trace below, haha):
```
---> 14 df.withColumn('ok', pandas_udf(f=ok, returnType='bigint')('id', b='id')).show() # no kwargs
TypeError: wrapper() got an unexpected keyword argument 'b'
```
Using partial with a keyword argument where the kw-arg is the first argument of the fn:
*(Aside: kind of interesting that lines 15,16 work great and then 17 explodes)*
```
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-9-e9f31b8799c1> in <module>()
15 df.withColumn('ok', pandas_udf(f=functools.partial(ok, 7), returnType='bigint')('id')).show()
16 df.withColumn('ok', pandas_udf(f=functools.partial(ok, b=7), returnType='bigint')('id')).show()
---> 17 df.withColumn('ok', pandas_udf(f=functools.partial(ok, a=7), returnType='bigint')('id')).show()
/Users/stu/ZZ/spark/python/pyspark/sql/functions.py in pandas_udf(f, returnType, functionType)
2378 return functools.partial(_create_udf, returnType=return_type, evalType=eval_type)
2379 else:
-> 2380 return _create_udf(f=f, returnType=return_type, evalType=eval_type)
2381
2382
/Users/stu/ZZ/spark/python/pyspark/sql/udf.py in _create_udf(f, returnType, evalType)
54 argspec.varargs is None:
55 raise ValueError(
---> 56 "Invalid function: 0-arg pandas_udfs are not supported. "
57 "Instead, create a 1-arg pandas_udf and ignore the arg in your function."
58 )
ValueError: Invalid function: 0-arg pandas_udfs are not supported. Instead, create a 1-arg pandas_udf and ignore the arg in your function.
```
Author: Michael (Stu) Stewart <mstewart141@gmail.com>
Closes#20900 from mstewart141/udfkw2.
## What changes were proposed in this pull request?
This cleans up unused imports, mainly from pyspark.sql module. Added a note in function.py that imports `UserDefinedFunction` only to maintain backwards compatibility for using `from pyspark.sql.function import UserDefinedFunction`.
## How was this patch tested?
Existing tests and built docs.
Author: Bryan Cutler <cutlerb@gmail.com>
Closes#20892 from BryanCutler/pyspark-cleanup-imports-SPARK-23700.
## What changes were proposed in this pull request?
The maxDF parameter is for filtering out frequently occurring terms. This param was recently added to the Scala CountVectorizer and needs to be added to Python also.
## How was this patch tested?
add test
Author: Huaxin Gao <huaxing@us.ibm.com>
Closes#20777 from huaxingao/spark-23615.
## What changes were proposed in this pull request?
Currently when a PySpark Model is transformed, default params that have not been explicitly set are then set on the Java side on the call to `wrapper._transfer_values_to_java`. This incorrectly changes the state of the Param as it should still be marked as a default value only.
## How was this patch tested?
Added a new test to verify that when transferring Params to Java, default params have their state preserved.
Author: Bryan Cutler <cutlerb@gmail.com>
Closes#18982 from BryanCutler/pyspark-ml-param-to-java-defaults-SPARK-21685.
## What changes were proposed in this pull request?
This PR proposes to remove out unused codes, `_ignore_brackets_split` and `_BRACKETS`.
`_ignore_brackets_split` was introduced in d57daf1f77 to refactor and support `toDF("...")`; however, ebc124d4c4 replaced the logics here. Seems `_ignore_brackets_split` is not referred anymore.
`_BRACKETS` was introduced in 880eabec37; however, all other usages were removed out in 648a8626b8.
This is rather a followup for ebc124d4c4 which I missed in that PR.
## How was this patch tested?
Manually tested. Existing tests should cover this. I also double checked by `grep` in the whole repo.
Author: hyukjinkwon <gurwls223@apache.org>
Closes#20878 from HyukjinKwon/minor-remove-unused.
## What changes were proposed in this pull request?
This PR proposes to add `lineSep` option for a configurable line separator in text datasource.
It supports this option by using `LineRecordReader`'s functionality with passing it to the constructor.
## How was this patch tested?
Manual tests and unit tests were added.
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#20727 from HyukjinKwon/linesep-text.
## What changes were proposed in this pull request?
d6632d185e added an useful util
```python
contextmanager
def sql_conf(self, pairs):
...
```
to allow configuration set/unset within a block:
```python
with self.sql_conf({"spark.blah.blah.blah", "blah"})
# test codes
```
This PR proposes to use this util where possible in PySpark tests.
Note that there look already few places affecting tests without restoring the original value back in unittest classes.
## How was this patch tested?
Manually tested via:
```
./run-tests --modules=pyspark-sql --python-executables=python2
./run-tests --modules=pyspark-sql --python-executables=python3
```
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#20830 from HyukjinKwon/cleanup-sql-conf.
## What changes were proposed in this pull request?
Added a class method to construct CountVectorizerModel from a list of vocabulary strings, equivalent to the Scala version. Introduced a common param base class `_CountVectorizerParams` to allow the Python model to also own the parameters. This now matches the Scala class hierarchy.
## How was this patch tested?
Added to CountVectorizer doctests to do a transform on a model constructed from vocab, and unit test to verify params and vocab are constructed correctly.
Author: Bryan Cutler <cutlerb@gmail.com>
Closes#16770 from BryanCutler/pyspark-CountVectorizerModel-vocab_ctor-SPARK-15009.
## What changes were proposed in this pull request?
Currently, some tests have an assumption that `spark.sql.sources.default=parquet`. In fact, that is a correct assumption, but that assumption makes it difficult to test new data source format.
This PR aims to
- Improve test suites more robust and makes it easy to test new data sources in the future.
- Test new native ORC data source with the full existing Apache Spark test coverage.
As an example, the PR uses `spark.sql.sources.default=orc` during reviews. The value should be `parquet` when this PR is accepted.
## How was this patch tested?
Pass the Jenkins with updated tests.
Author: Dongjoon Hyun <dongjoon@apache.org>
Closes#20705 from dongjoon-hyun/SPARK-23553.
## What changes were proposed in this pull request?
This PR proposes to fix the error message for Kinesis in PySpark when its jar is missing but explicitly enabled.
```bash
ENABLE_KINESIS_TESTS=1 SPARK_TESTING=1 bin/pyspark pyspark.streaming.tests
```
Before:
```
Skipped test_flume_stream (enable by setting environment variable ENABLE_FLUME_TESTS=1Skipped test_kafka_stream (enable by setting environment variable ENABLE_KAFKA_0_8_TESTS=1Traceback (most recent call last):
File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/.../spark/python/pyspark/streaming/tests.py", line 1572, in <module>
% kinesis_asl_assembly_dir) +
NameError: name 'kinesis_asl_assembly_dir' is not defined
```
After:
```
Skipped test_flume_stream (enable by setting environment variable ENABLE_FLUME_TESTS=1Skipped test_kafka_stream (enable by setting environment variable ENABLE_KAFKA_0_8_TESTS=1Traceback (most recent call last):
File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
File "/usr/local/Cellar/python/2.7.14_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/.../spark/python/pyspark/streaming/tests.py", line 1576, in <module>
"You need to build Spark with 'build/sbt -Pkinesis-asl "
Exception: Failed to find Spark Streaming Kinesis assembly jar in /.../spark/external/kinesis-asl-assembly. You need to build Spark with 'build/sbt -Pkinesis-asl assembly/package streaming-kinesis-asl-assembly/assembly'or 'build/mvn -Pkinesis-asl package' before running this test.
```
## How was this patch tested?
Manually tested.
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#20834 from HyukjinKwon/minor-variable.
