Java 使用junit@Rule、expectCause()和hamcrest匹配器
我有一个测试:Java 使用junit@Rule、expectCause()和hamcrest匹配器,java,unit-testing,maven,junit,Java,Unit Testing,Maven,Junit,我有一个测试: @Rule public ExpectedException thrown = ExpectedException.none(); ... @Test public void testMethod() { final String error = "error message"; Throwable expectedCause = new IllegalStateException(error); thrown.expectCause(org.hamcre
@Rule
public ExpectedException thrown = ExpectedException.none();
...
@Test
public void testMethod()
{
final String error = "error message";
Throwable expectedCause = new IllegalStateException(error);
thrown.expectCause(org.hamcrest.Matchers.<Throwable>equalTo(expectedCause));
someServiceThatTrowsException.foo();
}
@规则
抛出公共ExpectedException=ExpectedException.none();
...
@试验
公共void testMethod()
{
最终字符串error=“error message”;
Throwable expectedCause=新的非法状态异常(错误);
expectCause(org.hamcrest.Matchers.equalTo(expectedCause));
someServiceThrowsException.foo();
}
当通过mvn测试方法运行时,我得到错误:
java.lang.NoSuchMethodError:
org.junit.rules.ExpectedException.expectCause(Lorg/hamcrest/Matcher;)V
测试编译得很好
请帮助我,无法理解如何测试异常的原因?请尝试以下方法:
@Rule public ExpectedException thrown = ExpectedException.none();
@Test public void testMethod() throws Throwable {
final String error = "error message";
Throwable expectedCause = new IllegalStateException(error);
thrown.expectCause(IsEqual.equalTo(expectedCause));
throw new RuntimeException(expectedCause);
}
考虑不通过equals检查原因,而是在必要时通过IsInstanceOf和/或comapring异常消息进行检查。通过equals比较原因,同时检查stacktrace,这可能比您想要测试/检查的要多。例如:
@Rule public ExpectedException thrown = ExpectedException.none();
@Test public void testMethod() throws Throwable {
final String error = "error message";
thrown.expectCause(IsInstanceOf.<Throwable>instanceOf(IllegalStateException.class));
thrown.expectMessage(error);
throw new RuntimeException(new IllegalStateException(error));
}
@Rule public ExpectedException抛出=ExpectedException.none();
@Test public void testMethod()抛出可丢弃的{
最终字符串error=“error message”;
抛出.expectCause(IsInstanceOf.instanceOf(IllegalStateException.class));
抛出.expectMessage(错误);
抛出新的RuntimeException(新的IllegalStateException(错误));
}
这是JUnit版本的问题
ExpectedException.expectCause()
是自
中或更低版本中没有此类方法
您应该确保运行时JUnit版本>=4.11,与编译版本相同。您可以使用此处所述的自定义匹配器()来测试异常的原因 定制匹配器
使用静态导入并检查类和原因异常的消息时,要稍微简单一点:
import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.hasProperty;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.is;
import static org.junit.Assert.assertThat;
@Test
public void testThatThrowsNiceExceptionWithCauseAndMessages(){
expectedException.expect(RuntimeException.class );
expectedException.expectMessage("Exception message");
expectedException.expectCause(allOf(instanceOf(IllegalStateException.class),
hasProperty("message", is("Cause message"))) );
throw new RuntimeException("Exception message", new IllegalStateException("Cause message"));
}
您甚至可以使用hasProperty匹配器来断言嵌套原因或测试“getLocalizedMessage”方法 hamcrest的any(Class)matcher运行良好:
@Rule
public ExpectedException thrown = ExpectedException.none();
...
@Test
public void testMethod()
{
thrown.expect(RuntimeException.class);
thrown.expectCause(org.hamcrest.Matchers.any(IllegalStateException.class));
}
通常我更喜欢以下结构:
expectedException.expectCause(isA(NullPointerException.class));
导入
<dependency>
<groupId>it.ozimov</groupId>
<artifactId>java7-hamcrest-matchers</artifactId>
<version>1.3.0</version>
<scope>test</scope>
</dependency>
是奥齐莫夫
java7 hamcrest匹配器
1.3.0
测试
然后:
@Rule
public ExpectedException thrown = ExpectedException.none();
...
@Test
public void testMethod()
{
final String errorMessage = "error message";
Class<? extends Throwable> expectedCause = IllegalStateException.class;
thrown.expectCause(ExpectedException.exceptionWithMessage(expectedCause, errorMessage));
someServiceThatTrowsException.foo();
}
@规则
抛出公共ExpectedException=ExpectedException.none();
...
@试验
公共void testMethod()
{
最终字符串errorMessage=“error message”;
课堂总结所有内容
对于JUnit4(hamcrest 1.3,请注意,JUnit4依赖于hamcrest核心,不包括org.hamcrest.beans包)
因此,您需要导入:
org.hamcrest
汉克雷斯特酒店
1.3
测试
代码:
导入静态org.hamcrest.CoreMatchers.*;
导入静态org.hamcrest.beans.HasPropertyWithValue.hasProperty;
@统治
public ExpectedException ExpectedException=ExpectedException.none();
@试验
通过带有CauseAndMessages()的niceException的公共无效测试{
expect(RuntimeException.class);
expectedException.expectMessage(“异常消息”);
expectedException.expectedCause(
全部(
isA(IllegalStateException.class),
hasProperty(“消息”,即(“原因消息”))
)
);
扔
新的运行时异常(“异常消息”,
新的非法状态例外(“原因消息”);
}
您完全可以使用内置的matchersorg.hamcrest.matchers.instanceOf
和org.junit.internal.matchers.ThrowableMessageMatcher.hasMessage
:
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.both;
import static org.junit.internal.matchers.ThrowableMessageMatcher.hasMessage;
public class temp {
@Rule
public ExpectedException expectedException = ExpectedException.none();
@Test
public void youCannotDivideByZero() {
expectedException.expect(RuntimeException.class);
expectedException.expectMessage(equalTo("Division exception"));
expectedException.expectCause(both(hasMessage(equalTo("/ by zero"))).and(instanceOf(ArithmeticException.class)));
divide(1, 0);
}
private float divide(int first, int second) {
try {
return first / second;
} catch(ArithmeticException e) {
throw new RuntimeException("Division exception", e);
}
}
}
验证Kotlin语言的消息和引发异常的原因的示例:
@get:Rule
val exceptionRule: ExpectedException = ExpectedException.none()
@Test
fun `test method`() {
exceptionRule.expect(NestedServletException::class.java)
exceptionRule.expectMessage("error msg")
exceptionRule.expectCause(instanceOf(IllegalStateException::class.java))
// ...
我的意思是你的运行时JUnit版本,你可以试着调试代码。我目前也有同样的问题……对我来说,当我使用从父项目继承的依赖项时,问题就出现了,但现在当我在本地POM.xml中重新声明依赖项时。你找到解决方案了吗???@Dennis,没有。我使用标准的try/catch java习惯用法。如果不会抛出junit fail()。在catch块中,我会分析原因。谢谢。我现在会继续使用复制的依赖项,但会像您所做的那样退回到try-catch块。第二个示例是正确的方法。shown.expectCause(IsInstanceOf.instanceOf(java.io.IOException.class))
没问题,因为可以推断出该方法的来源:导入static org.hamcrest.CoreMatchers.isA;
虽然有用,但该问题与Kotlin无关,并且该答案没有解决所问的错误
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.both;
import static org.junit.internal.matchers.ThrowableMessageMatcher.hasMessage;
public class temp {
@Rule
public ExpectedException expectedException = ExpectedException.none();
@Test
public void youCannotDivideByZero() {
expectedException.expect(RuntimeException.class);
expectedException.expectMessage(equalTo("Division exception"));
expectedException.expectCause(both(hasMessage(equalTo("/ by zero"))).and(instanceOf(ArithmeticException.class)));
divide(1, 0);
}
private float divide(int first, int second) {
try {
return first / second;
} catch(ArithmeticException e) {
throw new RuntimeException("Division exception", e);
}
}
}
@get:Rule
val exceptionRule: ExpectedException = ExpectedException.none()
@Test
fun `test method`() {
exceptionRule.expect(NestedServletException::class.java)
exceptionRule.expectMessage("error msg")
exceptionRule.expectCause(instanceOf(IllegalStateException::class.java))
// ...