Rename class and freeze image versions

Author: JoshRosen

sql/core/src/test/scala/org/apache/spark/sql/jdbc/DockerHacks.scala renamed to sql/core/src/test/scala/org/apache/spark/sql/jdbc/DockerJDBCIntegrationSuite.scala

@@ -55,7 +55,7 @@ abstract class DatabaseOnDocker {
   def getJdbcUrl(ip: String, port: Int): String
 }
 
-abstract class DatabaseIntegrationSuite
+abstract class DockerJDBCIntegrationSuite
   extends SparkFunSuite
   with BeforeAndAfterAll
   with Eventually

sql/core/src/test/scala/org/apache/spark/sql/jdbc/MySQLIntegrationSuite.scala

@@ -21,9 +21,9 @@ import java.math.BigDecimal
 import java.sql.{Connection, Date, Timestamp}
 import java.util.Properties
 
-class MySQLIntegrationSuite extends DatabaseIntegrationSuite {
-  val db = new DatabaseOnDocker {
-    override val imageName = "mysql:latest"
+class MySQLIntegrationSuite extends DockerJDBCIntegrationSuite {
+  override val db = new DatabaseOnDocker {
+    override val imageName = "mysql:5.7.9"
     override val env = Map(
       "MYSQL_ROOT_PASSWORD" -> "rootpass"
     )

sql/core/src/test/scala/org/apache/spark/sql/jdbc/PostgresIntegrationSuite.scala

@@ -20,9 +20,9 @@ package org.apache.spark.sql.jdbc
 import java.sql.Connection
 import java.util.Properties
 
-class PostgresIntegrationSuite extends DatabaseIntegrationSuite {
-  val db = new DatabaseOnDocker {
-    override val imageName = "postgres:latest"
+class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
+  override val db = new DatabaseOnDocker {
+    override val imageName = "postgres:9.4.5"
     override val env = Map(
       "POSTGRES_PASSWORD" -> "rootpass"
     )