如何在 JUnit 测试中应用主文件中的方法?
How to apply a method from my main file in my JUnit test?
我们的作业说我们应该“为一个名为 sumArray
的函数编写源代码和测试代码,该函数接受一个整数数组和 return 数组中所有元素的总和”。
我想我已经 SumArray.java 到 return sum
好的,但是我正在努力将我的方法应用于测试输入。有什么帮助吗? TIA.
SumArray.java
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray();
}
}
SumArrayTest.java
package sumarray;
import org.junit.Test;
import static org.junit.Assert.*;
public class SumArrayTest {
public SumArrayTest() {
}
/**
* Test of main method, of class SumArray.
*/
@Test
public void testMain() {
System.out.println("main");
String[] args = null;
SumArray.main(args);
int[] intArray = new int[]{2, 3, 4};
int expectedResult = 9;
// int testResult = sumArray({2, 3, 4});
int testResult = SumArray sumArray(intArray);
assertEquals(expectedResult, testResult);
// fail("The test case is a prototype.");
}
}
编辑:我已经尝试通过一些更改来实现到目前为止所建议的内容;真的不确定这是对的;很多都是猜测TBH。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray;
public static int sumArray(int[] arr) {
return sum;
}
public static SumArray input() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return new SumArray();
}
public static void main(String[] args) {
SumArray result = input();
System.out.println(result.sumArray(SumArray));
}
}
package sumarray;
import org.junit.Test;
import static org.junit.Assert.*;
public class SumArrayTest {
public SumArrayTest() {
}
@Test
public void testSumArray() {
System.out.println("main");
String[] args = null;
int[] intArray = new int[]{2, 3, 4};
int expectedResult = 9;
assertEquals(expectedResult, SumArray.sumArray(intArray));
// fail("The test case is a prototype.");
}
}
我目前看到的唯一错误是 'cannot find symbol' for SumArray
in main
。
main() 方法是应用程序的入口点,您不应测试 main() 方法。相反,您应该测试 sumArray()
方法并比较预期的 Vs。方法的实际返回值。
附带说明一下,您最好将输入数组作为参数传递给 sumArray()
方法,而不是从方法主体中的 System.in
读取它。
所以你的方法签名可以是这样的:
public static int sumArray(int[] arr)
。使用此方法的客户端代码(这是您的案例(或单元测试)中的主要方法)可以传递数组,而无需打扰该输入数组的获取方式。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray();
}
}
以上是您贴出的原代码。现在,你说你得到了正确的输出。是的,你这样做:
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray(); // this one will return the correct answer
sumArray(); // this one will not
}
}
第二个会return错误的数据,因为你没有重新设置sum的值。
你应该拆分任务:sumArray 应该接收一个数组,并且应该 return 元素的总和。要么你应该更改方法的名称,要么更改实现,这是 Mahmoud 告诉你的。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static Scanner scan = new Scanner(System.in); // create this on class level, not every execution of your method
public static int[] buildArray(int elements) {
int[] arr = new int[elements];
for ( int i = 0; i < elements; i++ ) {
System.out.println("Enter element nr: " + (i+1));
arr[i] = scan.nextInt();
}
return arr;
}
public static int sumArray(int[] input) {
int sum = 0; // don't use a class level one. especially not a static one, it's value could be altered by another thread
for ( int in : input ) { // iterate over the array and add the values
sum += in; // this should be in -> each iteration we add the value of in (the element of the array) to sum
}
return sum;
}
public static void main(String[] args) {
System.out.println("Provide the size of the array: ");
int param = scan.nextInt();
int[] array = buildArray(param);
int result = sumArray(array);
System.out.println("The sum of the array is: " + result);
}
}
这种方法会让您遇到的问题要小得多。它也没有在您的 class 中可能导致错误结果的静态变量,例如 n 和 sum。
我们的作业说我们应该“为一个名为 sumArray
的函数编写源代码和测试代码,该函数接受一个整数数组和 return 数组中所有元素的总和”。
我想我已经 SumArray.java 到 return sum
好的,但是我正在努力将我的方法应用于测试输入。有什么帮助吗? TIA.
SumArray.java
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray();
}
}
SumArrayTest.java
package sumarray;
import org.junit.Test;
import static org.junit.Assert.*;
public class SumArrayTest {
public SumArrayTest() {
}
/**
* Test of main method, of class SumArray.
*/
@Test
public void testMain() {
System.out.println("main");
String[] args = null;
SumArray.main(args);
int[] intArray = new int[]{2, 3, 4};
int expectedResult = 9;
// int testResult = sumArray({2, 3, 4});
int testResult = SumArray sumArray(intArray);
assertEquals(expectedResult, testResult);
// fail("The test case is a prototype.");
}
}
编辑:我已经尝试通过一些更改来实现到目前为止所建议的内容;真的不确定这是对的;很多都是猜测TBH。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray;
public static int sumArray(int[] arr) {
return sum;
}
public static SumArray input() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return new SumArray();
}
public static void main(String[] args) {
SumArray result = input();
System.out.println(result.sumArray(SumArray));
}
}
package sumarray;
import org.junit.Test;
import static org.junit.Assert.*;
public class SumArrayTest {
public SumArrayTest() {
}
@Test
public void testSumArray() {
System.out.println("main");
String[] args = null;
int[] intArray = new int[]{2, 3, 4};
int expectedResult = 9;
assertEquals(expectedResult, SumArray.sumArray(intArray));
// fail("The test case is a prototype.");
}
}
我目前看到的唯一错误是 'cannot find symbol' for SumArray
in main
。
main() 方法是应用程序的入口点,您不应测试 main() 方法。相反,您应该测试 sumArray()
方法并比较预期的 Vs。方法的实际返回值。
附带说明一下,您最好将输入数组作为参数传递给 sumArray()
方法,而不是从方法主体中的 System.in
读取它。
所以你的方法签名可以是这样的:
public static int sumArray(int[] arr)
。使用此方法的客户端代码(这是您的案例(或单元测试)中的主要方法)可以传递数组,而无需打扰该输入数组的获取方式。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray();
}
}
以上是您贴出的原代码。现在,你说你得到了正确的输出。是的,你这样做:
package sumarray;
import java.util.Scanner;
public class SumArray {
private static int n, sum = 0;
public static int sumArray() {
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter the elements. (Press [return] after each one)");
for (int i = 0; i < n; i++) {
a[i] = s.nextInt();
sum = sum + a[i];
}
System.out.println("Sum:" + sum);
return sum;
}
public static void main(String[] args) {
sumArray(); // this one will return the correct answer
sumArray(); // this one will not
}
}
第二个会return错误的数据,因为你没有重新设置sum的值。
你应该拆分任务:sumArray 应该接收一个数组,并且应该 return 元素的总和。要么你应该更改方法的名称,要么更改实现,这是 Mahmoud 告诉你的。
package sumarray;
import java.util.Scanner;
public class SumArray {
private static Scanner scan = new Scanner(System.in); // create this on class level, not every execution of your method
public static int[] buildArray(int elements) {
int[] arr = new int[elements];
for ( int i = 0; i < elements; i++ ) {
System.out.println("Enter element nr: " + (i+1));
arr[i] = scan.nextInt();
}
return arr;
}
public static int sumArray(int[] input) {
int sum = 0; // don't use a class level one. especially not a static one, it's value could be altered by another thread
for ( int in : input ) { // iterate over the array and add the values
sum += in; // this should be in -> each iteration we add the value of in (the element of the array) to sum
}
return sum;
}
public static void main(String[] args) {
System.out.println("Provide the size of the array: ");
int param = scan.nextInt();
int[] array = buildArray(param);
int result = sumArray(array);
System.out.println("The sum of the array is: " + result);
}
}
这种方法会让您遇到的问题要小得多。它也没有在您的 class 中可能导致错误结果的静态变量,例如 n 和 sum。