HOTFIX: Fix Python tests on Jenkins.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #1036 from pwendell/jenkins-test and squashes the following commits:

9c99856 [Patrick Wendell] Better output during tests
71e7b74 [Patrick Wendell] Removing incorrect python path
74984db [Patrick Wendell] HOTFIX: Allow PySpark tests to run on Jenkins.

bin/pyspark

@@ -86,6 +86,10 @@ else
   if [[ "$IPYTHON" = "1" ]]; then
     exec ipython $IPYTHON_OPTS
   else
-    exec "$PYSPARK_PYTHON"
+    if [[ -n $SPARK_TESTING ]]; then
+      exec "$PYSPARK_PYTHON" -m doctest
+    else
+      exec "$PYSPARK_PYTHON"
+    fi
   fi
 fi

dev/run-tests

@@ -73,9 +73,6 @@ fi
 echo "========================================================================="
 echo "Running PySpark tests"
 echo "========================================================================="
-if [ -z "$PYSPARK_PYTHON" ]; then
-  export PYSPARK_PYTHON=/usr/local/bin/python2.7
-fi
 ./python/run-tests
 
 echo "========================================================================="

python/run-tests

@@ -32,7 +32,8 @@ rm -f unit-tests.log
 rm -rf metastore warehouse
 
 function run_test() {
-    SPARK_TESTING=0 $FWDIR/bin/pyspark $1 2>&1 | tee -a > unit-tests.log
+    echo "Running test: $1"
+    SPARK_TESTING=1 $FWDIR/bin/pyspark $1 2>&1 | tee -a > unit-tests.log
     FAILED=$((PIPESTATUS[0]||$FAILED))
 
     # Fail and exit on the first test failure.
@@ -46,15 +47,17 @@ function run_test() {
 
 }
 
+echo "Running PySpark tests. Output is in python/unit-tests.log."
+
 run_test "pyspark/rdd.py"
 run_test "pyspark/context.py"
 run_test "pyspark/conf.py"
 if [ -n "$_RUN_SQL_TESTS" ]; then
   run_test "pyspark/sql.py"
 fi
-run_test "-m doctest pyspark/broadcast.py"
-run_test "-m doctest pyspark/accumulators.py"
-run_test "-m doctest pyspark/serializers.py"
+run_test "pyspark/broadcast.py"
+run_test "pyspark/accumulators.py"
+run_test "pyspark/serializers.py"
 run_test "pyspark/tests.py"
 run_test "pyspark/mllib/_common.py"
 run_test "pyspark/mllib/classification.py"