Merge "EntropyMixerTest: convert to JUnit4" am: 7db3ab2c

package com.android.server;

import static org.junit.Assert.assertArrayEquals;

import static org.junit.Assert.assertEquals;

import static org.junit.Assert.assertFalse;

import static org.junit.Assert.assertTrue;

import android.content.Context;

import android.test.AndroidTestCase;

import androidx.test.InstrumentationRegistry;

import androidx.test.runner.AndroidJUnit4;

import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.io.File;

import java.nio.file.Files;

/**

 * Tests for {@link com.android.server.EntropyMixer}

 */

public class EntropyMixerTest extends AndroidTestCase {

@RunWith(AndroidJUnit4.class)

public class EntropyMixerTest {

    private static final int SEED_FILE_SIZE = EntropyMixer.SEED_FILE_SIZE;

    private File dir;

    private Context context;

    private File seedFile;

    private File randomReadDevice;

    private File randomWriteDevice;

    @Override

    @Before

    public void setUp() throws Exception {

        dir = getContext().getDir("test", Context.MODE_PRIVATE);

        seedFile = createTempFile(dir, "entropy.dat");

        randomReadDevice = createTempFile(dir, "urandomRead");

        randomWriteDevice = createTempFile(dir, "urandomWrite");

        context = InstrumentationRegistry.getTargetContext();

        seedFile = createTempFile("entropy.dat");

        randomReadDevice = createTempFile("urandomRead");

        randomWriteDevice = createTempFile("urandomWrite");

    }

    private File createTempFile(File dir, String prefix) throws Exception {

        File file = File.createTempFile(prefix, null, dir);

    private File createTempFile(String prefix) throws Exception {

        File file = File.createTempFile(prefix, null);

        file.deleteOnExit();

        return file;

    }

        // The constructor should have the side effect of writing to

        // randomWriteDevice and creating seedFile.

        new EntropyMixer(getContext(), seedFile, randomReadDevice, randomWriteDevice);

        new EntropyMixer(context, seedFile, randomReadDevice, randomWriteDevice);

        // Since there was no old seed file, the data that was written to

        // randomWriteDevice should contain only device-specific information.

        // The constructor should have the side effect of writing to

        // randomWriteDevice and updating seedFile.

        new EntropyMixer(getContext(), seedFile, randomReadDevice, randomWriteDevice);

        new EntropyMixer(context, seedFile, randomReadDevice, randomWriteDevice);

        // The data that was written to randomWriteDevice should consist of the

        // previous seed followed by the device-specific information.