Add SocketUtils CTS tests

/*

 * Copyright (C) 2019 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package android.net.util;

import android.system.NetlinkSocketAddress

import android.system.Os

import android.system.OsConstants.AF_INET

import android.system.OsConstants.ETH_P_ALL

import android.system.OsConstants.IPPROTO_UDP

import android.system.OsConstants.RTMGRP_NEIGH

import android.system.OsConstants.SOCK_DGRAM

import android.system.PacketSocketAddress

import androidx.test.filters.SmallTest

import androidx.test.runner.AndroidJUnit4

import org.junit.Assert.assertEquals

import org.junit.Assert.assertFalse

import org.junit.Assert.assertTrue

import org.junit.Assert.fail

import org.junit.Test

import org.junit.runner.RunWith

private const val TEST_INDEX = 123

private const val TEST_PORT = 555

@RunWith(AndroidJUnit4::class)

@SmallTest

class SocketUtilsTest {

    @Test

    fun testMakeNetlinkSocketAddress() {

        val nlAddress = SocketUtils.makeNetlinkSocketAddress(TEST_PORT, RTMGRP_NEIGH)

        if (nlAddress is NetlinkSocketAddress) {

            assertEquals(TEST_PORT, nlAddress.getPortId())

            assertEquals(RTMGRP_NEIGH, nlAddress.getGroupsMask())

        } else {

            fail("Not NetlinkSocketAddress object")

        }

    }

    @Test

    fun testMakePacketSocketAddress() {

        val pkAddress = SocketUtils.makePacketSocketAddress(ETH_P_ALL, TEST_INDEX)

        assertTrue("Not PacketSocketAddress object", pkAddress is PacketSocketAddress)

        val ff = 0xff.toByte()

        val pkAddress2 = SocketUtils.makePacketSocketAddress(TEST_INDEX,

                byteArrayOf(ff, ff, ff, ff, ff, ff))

        assertTrue("Not PacketSocketAddress object", pkAddress2 is PacketSocketAddress)

    }

    @Test

    fun testCloseSocket() {

        // Expect no exception happening with null object.

        SocketUtils.closeSocket(null)

        val fd = Os.socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)

        assertTrue(fd.valid())

        SocketUtils.closeSocket(fd)

        assertFalse(fd.valid())

        // Expecting socket should be still invalid even closed socket again.

        SocketUtils.closeSocket(fd)

        assertFalse(fd.valid())

    }

}