[SYSTEMDS-1896] Update python tests to use getOrCreate

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: SystemML 1.0.0
• Component/s: Test
• Environment: RedHat Linux 7.3 with Spark 2.1.0 and Hadoop 2.7.3.
• Sprint: Sprint 6
• Assignee: Glenn Weidner
• Reporter: Glenn Weidner
• Created: 07/Sep/17 00:41
• Updated: 17/Sep/17 04:50
• Resolved: 17/Sep/17 04:50

Description

Use SparkContext.getOrCreate or SparkSession.builder.getOrCreate in python tests to avoid "Cannot run multiple SparkContexts at once" error observed in some environments running scripts under src/main/python/tests with spark-submit.