Java IO，輸入流和輸出流測試

Question

我正在嘗試創建一個簡單的聊天程序。
最初，我編寫此代碼以根據給定的命令將來自用戶的輸入消息保存到文本文件中，但我對測試策略一無所知。 我應該只為runUi()編寫測試嗎？ 因為這個方法已經包含 switch 語句並且在它里面是調用的其他方法，還是我應該為所有其他方法編寫？

public class CmdLineUI implements ChatUI, Chat {
    public static final String WRITE = "write";
    public static final String READ = "read";
    public static final String EXIT = "exit";
    public static final String ERRORMESSAGE = "unknown command";

    private final PrintStream consoleOutput;
    private final BufferedReader userInput;

    public CmdLineUI(PrintStream os, InputStream is) {
        this.consoleOutput = os;
        this.userInput = new BufferedReader(new InputStreamReader(is));
    }

    public static void main(String[] args) throws Exception {
        PrintStream os = System.out;
        os.println("***Welcome to The ChatSystem:  input: write for chatting ,"
                + "\n    for Reading the messages input: read ,for closing Chat input: exit ***");

        CmdLineUI userCmd = new CmdLineUI(os, System.in);

        userCmd.runUi(System.in, os);
    }



    private String[] readCommands() throws Exception {
        String[] result = new String[1];
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);
        String commandLinString = null;
        String command = null;

        try {
            System.out.println("> ");

            commandLinString = br.readLine();
            StringTokenizer st = new StringTokenizer(commandLinString);
            command = st.nextToken().trim();
            // msg = st.nextToken();

            System.out.println("command :" + command);
        } catch (IOException e) {
            System.out.println("Exception when reading from comman line" + e.getLocalizedMessage());
        }
        result[0] = command;
        // result[1] = msg;

        return result;
    }

    @Override
    public void writeMessage(String message) throws Exception {
        System.out.println("Start with Writing mood:");

        try {
            File file = new File("/home/sami/Desktop/file.txt");
            InputStreamReader inputStreamReader = new InputStreamReader(System.in); // A stream for reading from the
                                                                                    // console
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader); // Connect InputStreamReader to a
                                                                                    // BufferedReader
            FileWriter fileReader = new FileWriter(file); // A stream that connects to the text file
            BufferedWriter bufferedWriter = new BufferedWriter(fileReader); // Connect the FileWriter to the
                                                                            // BufferedWriter
            String line;
            boolean continuee = true;

            while (!(line = bufferedReader.readLine()).equals("stop")) {
                continuee = false;
                bufferedWriter.write(line);
            }
            // Close the stream
            bufferedWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    @Override
    public void readMessage() throws Exception {
        System.out.println("start with reading mood:");

        File file = new File("/home/sami/Desktop/file.txt");
        FileInputStream fileinputstream = new FileInputStream(file);

        try {
            int oneByte;
            while ((oneByte = fileinputstream.read()) != -1) {
                System.out.write(oneByte);
            }

            System.out.flush();
        } catch (Exception ex) {
            ex.getMessage();
        }

        fileinputstream.close();
    }

    @Override
    public void runUi(InputStream inp, OutputStream outp) throws Exception {
        File file = new File("/home/sami/Desktop/file.txt");
        FileReader filereader = new FileReader(file);
        BufferedReader br = new BufferedReader(filereader);

        // CmdLineUI obj = new CmdLineUI(consoleOutput);
        PrintStream ps = new PrintStream(outp);
        boolean again = true;

        while (again) {
            String[] commandMsg = readCommands();
            String command = commandMsg[0];

            switch (command) {
            case WRITE:
                writeMessage(br.readLine());
                again = true;
                break;

            case READ:
                readMessage();
                again = true;
                break;

            case EXIT:    
                again = false;
                break;

            default:
                ps.println(ERRORMESSAGE);
            }
        }

    }

}

我已經創建了這兩個接口，這里是第一個

public interface ChatUI {
    public void runUi (InputStream inp, OutputStream outp) throws Exception;
}

第二個接口

public interface Chat {
     //First Method 
    public void writeMessage(String message)throws Exception;

    // Second Method
    public void readMessage()throws Exception;
}

Answer 1

為您的runUi()方法編寫測試，因為在所有其他方法中，您要么從控制台讀取並標記輸入String ，要么寫入文件，要么從文件讀取。 Oracle 和/或 Java 語言開發人員已經對所有這 3 個操作進行了測試（如果您想了解更多信息，可以通過谷歌搜索此過程）。

檢查您的程序流程是否按預期工作並為它們編寫測試，並且不要打擾您正在做的所有功能就是調用 Java API 然后除了從它返回（或寫入某處）之外幾乎什么都不做.

Answer 2

我用不同的方式再次編寫了這個程序，我也測試了這些方法：

import java.io.*;
import java.util.*;

public class CmdLineUI implements ChatUI, Chat {

    public static final String WRITE = "write";
    public static final String READ = "read";
    public static final String EXIT = "exit";
    public static final String ERRORMESSAGE = "unknown command";

    private BufferedReader userInput;

    public static void main(String[] args) throws Exception {
        PrintStream os = System.out;
        os.println("***Welcome to The ChatSystem:  input: write for chatting ,"
                + "\n    for Reading the messages input: read ,for closing Chat input: exit ***");

        CmdLineUI userCmd = new CmdLineUI();

        userCmd.runUi(System.in, System.out);

    }

    @Override
    public void writeMessage(String message) throws Exception {
        System.out.println("Start with Writing mode:");
        try {
            File file = new File("/home/sami/Desktop/file.txt");
            InputStreamReader inputStreamReader = new InputStreamReader(System.in); // A stream for reading from the
                                                                                    // console
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader); // Connect InputStreamReader to a
                                                                                    // BufferedReader

            FileWriter fileReader = new FileWriter(file); // A stream that connects to the text file
            BufferedWriter bufferedWriter = new BufferedWriter(fileReader); // Connect the FileWriter to the
                                                                            // BufferedWriter

            String line;
            boolean continuee = true;
            while (!(line = bufferedReader.readLine()).equals("stop")) {
                continuee = false;
                bufferedWriter.write(line);
            }

            // Close the stream
            bufferedWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    @Override
    public void readMessage() throws Exception {
        System.out.println("start with reading mode:");
        File file = new File("/home/sami/Desktop/file.txt");

        BufferedReader br = new BufferedReader(new FileReader(file));
        try {
            String oneByte;
            while ((oneByte = br.readLine()) != null) {
                System.out.println(oneByte);
            }

        }

        catch (Exception ex) {
            ex.getMessage();
        }

    }

    @Override
    public void runUi(InputStream inp, OutputStream outp) throws IOException {
        this.userInput = new BufferedReader(new InputStreamReader(inp));

        BufferedReader br = new BufferedReader(userInput);
        PrintStream ps = new PrintStream(outp);

        CmdLineUI userCmd = new CmdLineUI();

        String commandLinString = null;
        boolean again = true;
        try {
            while (again) {

                System.out.println("> ");
                commandLinString = br.readLine().trim();
                StringTokenizer st = new StringTokenizer(commandLinString);
                String command = st.nextToken();
                // String msg= userCmd.readCommands(command);
                System.out.println("command :" + command);
                switch (command) {

                case WRITE:

                    writeMessage(command);
                    again = true;
                    break;

                case READ:

                    readMessage();

                    again = true;
                    break;
                case EXIT:

                    again = false;
                    break;
                default:
                    ps.println(ERRORMESSAGE);
                }

            }

        } catch (Exception e) {
            System.out.println("Exception when reading from comman line" + e.getLocalizedMessage());

        }

    }

}

這是測試：

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

import junit.framework.Assert;

import java.io.*;

class CmdTesting {



    @Test
    void test() throws Exception {
        try {
            CmdLineUI obj = new CmdLineUI();

            InputStream myInputStream = null;

            String unknownCommandString = "hello world";
            String exitString = CmdLineUI.EXIT;

            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            DataOutputStream dos = new DataOutputStream(baos);
            dos.writeUTF(unknownCommandString);

            byte[] inputBytes = baos.toByteArray();

            ByteArrayInputStream bais = new ByteArrayInputStream(inputBytes);
            myInputStream = bais;

            ByteArrayOutputStream myOutputStream = new ByteArrayOutputStream();

            obj.runUi(myInputStream, myOutputStream);

            ByteArrayInputStream outputIS = new ByteArrayInputStream(myOutputStream.toByteArray());

            DataInputStream dis = new DataInputStream(outputIS);

            dis.readUTF();

            String expected = "hello world";

            assertEquals(expected, unknownCommandString);

        } catch (Exception ex) {
            ex.getLocalizedMessage();
        }

    }

    @Test
    public void writeMessage() throws Exception {

        File file = new File("/home/sami/Desktop/file.txt");
        String str = "Hello";

        BufferedWriter writer = new BufferedWriter(new FileWriter(file, true));
        writer.append(' ');
        writer.append(str);

        writer.close();
    }


    @Test
    public void reamessage() throws Exception {
        File file=new File("/home/sami/Desktop/file.txt");

        BufferedReader reader = new BufferedReader(new FileReader(file));
        reader.read();
    }
}