如何解决模拟输入蒸汽似乎在 Junit 测试的第一个输入中被吃掉了
使用我在这里找到的解决方案： https://www.generacodice.com/en/articolo/133943/JUnit:+How+to+simulate+System.in+testing%3F
我尝试在我为课堂编写的 connect4 游戏上为我的主游戏循环编写 JUnit 测试。然而，虽然它让我通过了第一个输入，但在第二个输入中我得到了一个“java.util.NoSuchElementException: No line found”错误。
我试过 "1\n2\n1\n2\n1\n2\n1\n2\n1\n" 和 "1\n\r2\n\r1\n\r2\n\r1\n\ r2\n\r1\n\r2\n\r1\n\r"而没有改变问题。
我尝试将其缩减为“1\n2\n”和“1\n\r2\n\r”，因为它在第二个条目上失败了。如果我能通过第二个条目，那么显然我可以进入第三个、第四个等等。基本上，1 表示“这是一个文字游戏”，2 表示“两个人类玩家”。流的其余部分是游戏开始后的一系列移动，因此此时并不重要，因为我无法在单元测试中到达那里。
它通过了这个......
public static boolean text_or_gi() {
System.out.println("For text based,enter 1,"
+ " for Graphical play,enter 2.");
int players = 1;
boolean entered_int = false;
Scanner input = new Scanner(system.in);
do{
if(input.hasNextInt())
{
players = input.nextInt();
try
{
if (players >= 1 && players < 3)
{
entered_int = true;
}
else
throw new ArithmeticException("1 or 2 player only");
}
catch (ArithmeticException e)
{
Connect4TextConsole.invalid_move();
System.out.println(e.getMessage());
}
}
else
{
input.nextLine();
//tell them to enter a valid number
Connect4TextConsole.invalid_move();
}
}
while(!entered_int);
return players == 1;
}
但后来到了这个 -
public boolean aiOpponent()
{
Connect4TextConsole.one_or_two_player();
int players = 1;
boolean entered_int = false;
Scanner input = new Scanner(system.in);
do{
if(input.hasNextInt())
{
players = input.nextInt();
try
{
if (players >= 1 && players < 3)
entered_int = true;
else
throw new ArithmeticException("1 or 2 player only");
}
catch (ArithmeticException e)
{
Connect4TextConsole.invalid_move();
System.out.println(e.getMessage());
}
}
else
{
input.nextLine();
//tell them to enter a valid number
Connect4TextConsole.invalid_move();
}
}
while(!entered_int);
return players == 1;
}
然后失败并出现此错误。
java.util.NoSuchElementException：未找到行
at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
at core.Connect4ComputerPlayer.aiOpponent(Connect4ComputerPlayer.java:43)
at core.Connect4.game_loop(Connect4.java:102)
at core.Connect4.main(Connect4.java:66)
at TestConnect4.testMainGameLoop(TestConnect4.java:60)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runchild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runchild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runchildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
看起来输入的蒸汽用完了，好像我只有'1/n'
import static org.junit.Assert.*;
import core.*;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintStream;
public class TestConnect4 {
// for simulating user input
private static final InputStream systemIn = system.in;
private static final PrintStream systemOut = System.out;
private ByteArrayInputStream testIn;
private ByteArrayOutputStream testOut;
private static String testInput1;
private static String testInput2;
private static String testInput3;
//Connect4 core objects
private static Connect4 game;
private void provideInput(String data) {
testIn = new ByteArrayInputStream(data.getBytes());
System.setIn(testIn);
}
private String getoutput() {
return testOut.toString();
}
public static void restoreSystemInputOutput() {
System.setIn(systemIn);
System.setout(systemOut);
}
@BeforeClass
public static void setUpBeforeClass() throws Exception
{
// It seems like the first time it reaches an input,it eats the entire stream,so I can't get this first test to work.
testInput1 = "1\n\r2\n\r1\n\r2\n\r1\n\r2\n\r1\n\r2\n\r1\n\r";
game = new Connect4();
}
@AfterClass
public static void tearDownAfterClass() throws Exception
{
restoreSystemInputOutput();
testInput1 = null;
game = null;
}
@Test
public void testMainGameLoop() {
// It fails on Enter Number of Human Players,with a NoSuchElementException. I think
// that the first time Scanner is called,it's eating the entire input,but that shouldn't
// happen.
provideInput(testInput1);
Connect4.main(new String[0]);
assertTrue("red won",getoutput().contains("Player X – you win!"));
}
}
编辑： 我在一天中扩展了我的测试，包括以较小的方式使用上述方法，并且它适用于那些较小的部分，但并没有让我几乎让主游戏循环测试工作。
import static org.junit.Assert.*;
import core.*;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintStream;
import java.util.Arrays;
import java.util.Scanner;
public class TestConnect4 {
// for simulating user input
private static final InputStream systemIn = system.in;
private static final PrintStream systemOut = System.out;
private ByteArrayInputStream testIn;
private ByteArrayOutputStream testOut;
private static String testInput1;
private static String testInput2;
private static String testInput3;
private static String testInput4;
//Connect4 core objects
private static Connect4 game;
private static Connect4ComputerPlayer ai;
private void provideInput(String data) {
testIn = new ByteArrayInputStream(data.getBytes());
System.setIn(testIn);
}
public void setUpOutput() {
testOut = new ByteArrayOutputStream();
System.setout(new PrintStream(testOut));
}
private String getoutput() {
return testOut.toString();
}
public static void restoreSystemInputOutput() {
System.setIn(systemIn);
System.setout(systemOut);
}
@BeforeClass
public static void setUpBeforeClass() throws Exception
{
// It seems like the first time it reaches an input,so I can't get this first test to work.
testInput1 = "1\n\r2\n\r1\n\r2\n\r1\n\r2\n\r1\n\r2\n\r1\n\r";
testInput2 = "1\n";
testInput3 = "2\n";
testInput4 = "3\n2\n";
game = new Connect4();
ai = new Connect4ComputerPlayer();
}
@Before
public void setUp() throws Exception
{
game = new Connect4();
}
@AfterClass
public static void tearDownAfterClass() throws Exception
{
restoreSystemInputOutput();
testInput1 = null;
game = null;
ai = null;
}
@Test
public void testMainGameLoop() {
//// It fails on Enter Number of Human Players,with a NoSuchElementException. I think
//// that the first time Scanner is called,but that shouldn't
//// happen.
provideInput(testInput1);
setUpOutput();
Connect4.main(new String[0]);
assertTrue( getoutput().contains("human players"));
restoreSystemInputOutput();
}
@Test
public void testinilization()
{
assertEquals(game.getGamestate(),'p');
game.setGamestate('T');
assertEquals(game.getGamestate(),'T');
assertEquals(game.getPlayer(),'X');
game.setPlayer('O');
assertEquals(game.getPlayer(),'O');
assertEquals(game.getComputer_move(),0);
game.setComputer_move(1);
assertEquals(game.getComputer_move(),1);
int[][] columns = new int[7][6];
for (int[] row: columns)
Arrays.fill(row,0);
assertEquals(game.getColumns(),columns);
columns[0][0] = -1;
game.setColumns(columns);
assertEquals(game.getColumns(),columns);
assertEquals(game.isTwoplayer(),false);
game.setTwoplayer(true);
assertEquals(game.isTwoplayer(),true);
game.setInput(new Scanner(system.in));
assertNotNull(game.getinput());
}
@Test
public void testWinCondition()
{
int[][] columns = new int[7][6];
for (int[] row: columns)
Arrays.fill(row,1);
game.win_condition();
assertEquals(game.getGamestate(),'p');
game.setColumns(columns);
game.win_condition();
assertEquals(game.getGamestate(),'T');
game.setPlayer('O');
game.win_condition();
assertEquals(game.getGamestate(),'O');
for (int[] row: columns)
Arrays.fill(row,-1);
game.setPlayer('X');
game.setColumns(columns);
game.win_condition();
assertEquals(game.getGamestate(),'X');
game.setGamestate('p');
for (int[] row: columns)
Arrays.fill(row,0);
columns[0][0] = columns[1][0] = columns[2][0] = columns[3][0] = -1;
game.win_condition();
assertEquals(game.getGamestate(),0);
columns[0][0] = columns[1][1] = columns[2][2] = columns[3][3] = -1;
game.win_condition();
assertEquals(game.getGamestate(),0);
columns[3][0] = columns[2][1] = columns[1][2] = columns[0][3] = -1;
game.win_condition();
assertEquals(game.getGamestate(),'X');
game.setPlayer('O');
for (int[] row: columns)
Arrays.fill(row,0);
columns[0][0] = columns[1][0] = columns[2][0] = columns[3][0] = 1;
game.win_condition();
assertEquals(game.getGamestate(),'O');
game.setGamestate('p');
for (int[] row: columns)
Arrays.fill(row,0);
columns[0][0] = columns[1][1] = columns[2][2] = columns[3][3] = 1;
game.win_condition();
assertEquals(game.getGamestate(),0);
columns[3][0] = columns[2][1] = columns[1][2] = columns[0][3] = 1;
game.win_condition();
assertEquals(game.getGamestate(),'O');
}
@Test
public void testPlayTurn()
{
int[][] columns = new int[7][6];
for (int[] row: columns)
Arrays.fill(row,1);
assertTrue(game.play_turn(0));
game.setColumns(columns);
assertFalse(game.play_turn(0));
game.setPlayer('O');
columns[6][5] = 0;
assertTrue(game.play_turn(6));
}
@Test
public void testaiOpponent()
{
provideInput(testInput2);
assertTrue(ai.aiOpponent(new Scanner(system.in)));
provideInput(testInput3);
assertFalse(ai.aiOpponent(new Scanner(system.in)));
provideInput(testInput4);
assertFalse(ai.aiOpponent(new Scanner(system.in)));
int[][] columns = new int[7][6];
for (int[] row: columns)
Arrays.fill(row,0);
assertTrue(ai.make_move(columns) < 7 && ai.make_move(columns) >= 0);
}
@Test
public void testFinalState()
{
setUpOutput();
game.setGamestate('X');
Connect4.final_state(game);
assertTrue(getoutput().contains("X"));
game.setGamestate('O');
Connect4.final_state(game);
assertTrue(getoutput().contains("O"));
game.setGamestate('T');
Connect4.final_state(game);
assertTrue(getoutput().contains("The Game was Tied."));
game.setGamestate('F');
Connect4.final_state(game);
assertTrue(getoutput().contains("The game has entered a Failed state."));
}
}
所以这个方法肯定有效。不知何故，当我测试主游戏循环时，我会转储流，但当我在各个部分尝试时不会转储，但我不知道我在哪里做。
解决方法
所以我发现我的第一个猜测是，我需要创建一个扫描仪并重复使用它，这是正确的。但是，扫描器不能是静态扫描器 - 所以我在 Main 中创建了一个扫描器，并在我在应用程序中移动时将它依次传递给每个方法。
这显然是一个有缺陷的解决方案，应该有更好的方法来做到这一点，因为这不是您编写“真正”程序的方式，但它确实解决了像这样的家庭作业的问题您的工作是在单元测试中获得一定比例的覆盖率，而不是真正做好单元测试。
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