如何为这段代码编写适当的 JUnit 测试？

Question

我是编程新手。我必须为此程序编写 JUnit 测试以找到 GCD，如下所示：

public class CoprimeNumbersTest {


/**
 * Given two integers, this returns true if they are relatively prime and  false if they are not. Based upon the first
 * webpage I found ({@link "https://primes.utm.edu/notes/faq/negative_primes.html"}), the primality of negative
 * numbers is up for debate. This method will not treat negatives differently.
 *
 * @param a First integer to be tested
 * @param b Second integer to be tested
 * @return True when the greatest common divisor of these numbers is 1; false otherwise.
 */
public boolean isCoprime(int a, int b) {
  // Continue using Euclid's algorithm until we find a common divisor
  while (b != 0) {
// Remember b's value
int temp = b;
// Set b to the remainder of dividing a by b (e.g., a mod b).
b = a % b;
// Set a equal to b's old value.
a = temp;
  }
   // The gcd is the value in a. If this is 1 the numbers are coprime.
   if (a == 1) {
return true;
     }
  // When they are not 1, they have a common divisor.
  else {
return false;
  }
}
}

这是我能想到的：

public class CoPrimetest {

    @Test
    public void testing() { 
        assetEquals(1, GCDFinder.CoprimeNumbersTest);
    }

}

是否有任何我遗漏的方法可以帮助改进我的代码？

Answer 1

您需要实际调用您的方法，就像在普通代码中一样。（以下代码没有测试，不知道1和1其实是不是co-prime。）

public class CoPrimetest {

    @Test
    public void testing() { 
       CoprimeNumbersTest instance = new CoprimeNumbersTest();
       boolean result = instance.isCoprime( 1, 1 );
       boolean expected = true;
       assertEquals( expected, result );
    }
}

Answer 2

针对 CoprimeNumbersTest class 中的 isCoprime 方法编写的示例测试方法可能是

@org.junit.Test
public void isCoprime() throws Exception {
    org.junit.Assert.assertEquals(true, new CoprimeNumbersTest().isCoprime(3,4)); 
}

由于 return 类型的方法是 boolean，您可以断言它等于 true 或 false。

建议，尝试使用这些输入 (3,4) 干燥运行 isCoprime 方法，并找出所有语句都已涵盖的内容。基于此推断如果您提供的输入将涵盖其余的陈述。这应该有助于用单元测试覆盖代码。

附带说明一下，尝试重命名您的 classes 以实践更好的命名约定，例如 GreatestCommonDivisor.java 和 GreatestCommonDivisorTest.java 也将它们链接起来。

如何为这段代码编写适当的 JUnit 测试？

How Can I Write a Proper JUnit Test for this code?

java

junit

greatest-common-divisor