Fix the unit tests

Author: zsxwing

sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala

@@ -150,11 +150,12 @@ private[spark] object SQLConf {
         doc: String = "",
         isPublic: Boolean = true): SQLConfEntry[T] =
       SQLConfEntry(key, defaultValue, v => {
-        if (!validValues.contains(v)) {
+        val _v = valueConverter(v)
+        if (!validValues.contains(_v)) {
           throw new IllegalArgumentException(
             s"The value of $key should be one of ${validValues.mkString(", ")}, but was $v")
         }
-        valueConverter(v)
+        _v
       }, _.toString, doc, isPublic)
   }
 
@@ -225,7 +226,7 @@ private[spark] object SQLConf {
     doc = "Turns on caching of Parquet schema metadata. Can speed up querying of static data.")
 
   val PARQUET_COMPRESSION = enumConf("spark.sql.parquet.compression.codec",
-    valueConverter = v => v,
+    valueConverter = v => v.toLowerCase,
     validValues = Set("uncompressed", "snappy", "gzip", "lzo"),
     defaultValue = Some("gzip"),
     doc = "Sets the compression codec use when writing Parquet files. Acceptable values include: " +

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -910,25 +910,25 @@ class SQLQuerySuite extends QueryTest with BeforeAndAfterAll with SQLTestUtils {
     sql(s"SET $testKey=$testVal")
     checkAnswer(
       sql("SET"),
-      Row(s"$testKey=$testVal")
+      Row(testKey, testVal)
     )
 
     sql(s"SET ${testKey + testKey}=${testVal + testVal}")
     checkAnswer(
       sql("set"),
       Seq(
-        Row(s"$testKey=$testVal"),
-        Row(s"${testKey + testKey}=${testVal + testVal}"))
+        Row(testKey, testVal),
+        Row(testKey + testKey, testVal + testVal))
     )
 
     // "set key"
     checkAnswer(
       sql(s"SET $testKey"),
-      Row(s"$testKey=$testVal")
+      Row(testKey, testVal)
     )
     checkAnswer(
       sql(s"SET $nonexistentKey"),
-      Row(s"$nonexistentKey=<undefined>")
+      Row(nonexistentKey, "<undefined>")
     )
     sqlContext.conf.clear()
   }