[SPARK-9580] [SQL] Replace singletons in SQL tests

A fundamental limitation of the existing SQL tests is that *there is simply no way to create your own `SparkContext`*. This is a serious limitation because the user may wish to use a different master or config. As a case in point, `BroadcastJoinSuite` is entirely commented out because there is no way to make it pass with the existing infrastructure.

This patch removes the singletons `TestSQLContext` and `TestData`, and instead introduces a `SharedSQLContext` that starts a context per suite. Unfortunately the singletons were so ingrained in the SQL tests that this patch necessarily needed to touch *all* the SQL test files.

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Author: Andrew Or <andrew@databricks.com>

Closes #8111 from andrewor14/sql-tests-refactor.

1 files changed, 10 insertions, 0 deletions

diff --git a/project/MimaExcludes.scala b/project/MimaExcludes.scala
index 784f83c10e..88745dc086 100644
--- a/project/MimaExcludes.scala
+++ b/project/MimaExcludes.scala
@@ -179,6 +179,16 @@ object MimaExcludes {
             ProblemFilters.exclude[MissingMethodProblem](
               "org.apache.spark.SparkContext.supportDynamicAllocation")
           ) ++ Seq(
+            // SPARK-9580: Remove SQL test singletons
+            ProblemFilters.exclude[MissingClassProblem](
+              "org.apache.spark.sql.test.LocalSQLContext$SQLSession"),
+            ProblemFilters.exclude[MissingClassProblem](
+              "org.apache.spark.sql.test.LocalSQLContext"),
+            ProblemFilters.exclude[MissingClassProblem](
+              "org.apache.spark.sql.test.TestSQLContext"),
+            ProblemFilters.exclude[MissingClassProblem](
+              "org.apache.spark.sql.test.TestSQLContext$")
+          ) ++ Seq(
             // SPARK-9704 Made ProbabilisticClassifier, Identifiable, VectorUDT public APIs
             ProblemFilters.exclude[IncompatibleResultTypeProblem](
               "org.apache.spark.mllib.linalg.VectorUDT.serialize")