[SPARK-16538][SPARKR] Add more tests for namespace call to SparkSession functions

## What changes were proposed in this pull request?

More tests
I don't think this is critical for Spark 2.0.0 RC, maybe Spark 2.0.1 or 2.1.0.

## How was this patch tested?

unit tests

shivaram dongjoon-hyun

Author: Felix Cheung <[email protected]>

Closes #14206 from felixcheung/rroutetests.

Author: felixcheung

R/pkg/inst/tests/testthat/test_sparkSQL.R

@@ -2424,6 +2424,13 @@ test_that("createDataFrame sqlContext parameter backward compatibility", {
   before <- suppressWarnings(createDataFrame(sqlContext, iris))
   after <- suppressWarnings(createDataFrame(iris))
   expect_equal(collect(before), collect(after))
+
+  # more tests for SPARK-16538
+  createOrReplaceTempView(df, "table")
+  SparkR::tables()
+  SparkR::sql("SELECT 1")
+  suppressWarnings(SparkR::sql(sqlContext, "SELECT * FROM table"))
+  suppressWarnings(SparkR::dropTempTable(sqlContext, "table"))
 })
 
 test_that("randomSplit", {