[开发测试]单元测试学习汇总

原文链接：https://www.jianshu.com/p/e39bafff7714

1、 创建一个被测试类：FileUtil

package UT_Test;

import java.io.File;
import java.io.FileNotFoundException;

public class FileUtil {

    private static final String LOG_FILE = "root.log";

    public boolean mkdirs(String path) {
        log("start to mkdirs:" + path);
        File fileDir = new File(path);
        if (fileDir.exists()) {
            throw new IllegalArgumentException(path + "alreay exists!");
        } else {
            return fileDir.mkdirs();
        }
    }

    public File getLogFile() throws FileNotFoundException {
        log("start to get log file");
        String logPath = System.getenv("LOG_PATH");
        if (null == logPath) {
            throw new IllegalArgumentException("System env:LOG_PATH not exist!");
        }
        if (isExists(logPath)) {
            return new File(logPath + LOG_FILE);
        }
        throw new FileNotFoundException("File " + logPath + LOG_FILE + "not exist!");
    }

    private boolean isExists(String logPath) {
        return false;
    }

    public void log(String log) {
        System.out.println(log);
    }
}

2、测试类：FileUtilMkdirTest

package UT_Test;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import java.io.File;
import java.io.FileNotFoundException;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

/**
 * 参考链接：
 *      https://www.jianshu.com/p/e39bafff7714
 */
@RunWith(PowerMockRunner.class)
@PrepareForTest(FileUtil.class)
public class FileUtilMkdirTest {
    @Before
    public void init() throws Exception {
        File fileDir = PowerMockito.mock(File.class);
        PowerMockito.whenNew(File.class).withAnyArguments().thenReturn(fileDir);
        PowerMockito.when(fileDir.exists()).thenReturn(false);
        PowerMockito.when(fileDir.mkdirs()).thenReturn(true);
    }

    @Test
    public void testMkdirs() {
        assertTrue(new FileUtil().mkdirs("testDir"));
    }

    @Test
    public void testGetLogFileWithException() {
        PowerMockito.mockStatic(System.class);
        PowerMockito.when(System.getenv("LOG_PATH")).thenReturn("./");
        try {
            new FileUtil().getLogFile();
            fail();
        } catch (FileNotFoundException e) {
            assertTrue(true);
        }
    }
    @Test
    public void testGetLogFile() throws Exception {
        PowerMockito.mockStatic(System.class);
        PowerMockito.when(System.getenv("LOG_PATH")).thenReturn("./");

        FileUtil fileUtil = PowerMockito.spy(new FileUtil());
        PowerMockito.when(fileUtil, "isExists", "./").thenReturn(true);

        File logFile = fileUtil.getLogFile();
        assertTrue(logFile != null);
    }
    @Test
    public void testGetLogFileWithoutLog() throws Exception {
        PowerMockito.mockStatic(System.class);
        PowerMockito.when(System.getenv("LOG_PATH")).thenReturn("./");

        FileUtil fileUtil = PowerMockito.spy(new FileUtil());
        PowerMockito.when(fileUtil, "isExists", "./").thenReturn(true);
        PowerMockito.doNothing().when(fileUtil, "log", Mockito.anyString());

        File logFile = fileUtil.getLogFile();
        assertTrue(logFile != null);
    }
}

3、 相关链接：

(1) JUnit单元测试5—PowerMock
https://www.jianshu.com/p/e39bafff7714
(2) 单元测试之PowerMock
https://www.cnblogs.com/kancy/p/13912443.html