Use random port for Cassandra tests

Closes gh-4028

spring-boot-samples/spring-boot-sample-data-cassandra/pom.xml

@@ -35,12 +35,40 @@
 		<dependency>
 		    <groupId>org.cassandraunit</groupId>
 		    <artifactId>cassandra-unit-spring</artifactId>
-		    <version>2.1.3.1</version>
+		    <version>2.1.9.2</version>
 		    <scope>test</scope>
 		</dependency>
 	</dependencies>
 	<build>
 		<plugins>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>build-helper-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>reserve-cassandra-port</id>
+						<goals>
+							<goal>reserve-network-port</goal>
+						</goals>
+						<phase>process-resources</phase>
+						<configuration>
+							<portNames>
+								<portName>cassandra.port</portName>
+							</portNames>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<configuration>
+					<systemPropertyVariables>
+						<spring.data.cassandra.port>${cassandra.port}</spring.data.cassandra.port>
+						<cassandra.native_transport_port>${cassandra.port}</cassandra.native_transport_port>
+					</systemPropertyVariables>
+				</configuration>
+			</plugin>
 			<plugin>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>