JUnit : 테스트 예외가 작동하지 않음 (AssertionError : 예외가 발생하더라도 예상되는 예외)

클래스에서 예외를 테스트하려고합니다. 나는 몇 가지 다른 방법을 시도해 왔지만 아무것도 작동하지 않습니다. 내가 여기서 뭘 잘못하고 있니?

테스트하려는 클래스 PrimeNumber.java :

public class PrimeNumber {

    static final Logger LOG = LogManager.getLogger("Log");

    private String primeNumberStr;

    public PrimeNumber(String primeNumberStr) {
        this.primeNumberStr = primeNumberStr;
    }

    public String getPrimeResult() {
        String resultStr = "";
        try {
            // Convert user input to int
            int primeNumberInt = Integer.parseInt(primeNumberStr);
            // Beginning of return message
            resultStr += primeNumberInt + " is ";
            // Add "not" if it's not a prime
            if (!Primes.isPrime(primeNumberInt))
                resultStr += "NOT ";
            // End return message
            resultStr += "a prime";
            // If not a valid number, catch
        } catch (NumberFormatException e) {
            // Log exception
            LOG.warn("NumberFormatException" + e.getMessage());
            // If empty user input
            if (primeNumberStr.length() == 0)
                resultStr += "No number inserted";
            // Else not empty but not valid
            else
                resultStr += primeNumberStr + " is not a valid number";
            resultStr += ". Only numbers without decimals are accepted.";
        }

        return resultStr;
    }

}

그리고 이제 내가 테스트하려고 시도한 것 :

주석 포함

@Test(expected = NumberFormatException.class)
public void testNumberFormatExceptionBeingThrown() {
    PrimeNumber primeNumber = new PrimeNumber("6dg");
    primeNumber.getPrimeResult();
}

실패한 테스트 결과 :

java.lang.AssertionError: Expected exception: java.lang.Exception

JUnit 규칙 사용 :

@Rule public ExpectedException thrown = ExpectedException.none();

@Test(expected = NumberFormatException.class)
public void testNumberFormatExceptionBeingThrown() {
    thrown.expect(NumberFormatException.class);
    thrown.expectMessage("For input string: \"a21\"");
    PrimeNumber primeNumber = new PrimeNumber("a21");
    primeNumber.getPrimeResult();
}

결과 :

java.lang.AssertionError: Expected test to throw (an instance of java.lang.NumberFormatException and exception with message a string containing "For input string: \"a21\"")
at org.junit.Assert.fail(Assert.java:88)
at org.junit.rules.ExpectedException.failDueToMissingException(ExpectedException.java:263)
at org.junit.rules.ExpectedException.access$200(ExpectedException.java:106)
at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:245)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
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.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:78)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:212)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)