JUnit5依赖注入与测试接口
作者:互联网
依赖注入
以前的JUnit的类构造方法和测试方法都是不能有参数的,JUnit Jupiter有一个颠覆性的改进,就是允许它们有入参,这样就能做依赖注入了。
如果你对pytest的fixture有了解的话,就知道这个技术是多么的强大。
ParameterResolver是一个接口类,类构造方法和测试方法在运行时,必须由被注册的ParameterResolver进行解析。JUnit Jupiter有三个自动注册的内置解析器:
- TestInfoParameterResolver 参数类型为TestInfo
- RepetitionInfoParameterResolver 参数类型为RepetitionInfo
- TestReporterParameterResolver 参数类型为TestReporter
TestInfo
TestInfo包含the display name, the test class, the test method, and associated tags等信息。
示例:
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestInfo;
@DisplayName("TestInfo Demo")
class TestInfoDemo {
TestInfoDemo(TestInfo testInfo) {
assertEquals("TestInfo Demo", testInfo.getDisplayName());
}
@BeforeEach
void init(TestInfo testInfo) {
String displayName = testInfo.getDisplayName();
assertTrue(displayName.equals("TEST 1") || displayName.equals("test2()"));
}
@Test
@DisplayName("TEST 1")
@Tag("my-tag")
void test1(TestInfo testInfo) {
assertEquals("TEST 1", testInfo.getDisplayName());
assertTrue(testInfo.getTags().contains("my-tag"));
}
@Test
void test2() {
}
}
RepetitionInfo
主要是@RepeatedTest
会用到,包含当前重复以及总重复次数等信息。
TestReporter
TestReporter能用来输出额外的信息。
示例:
class TestReporterDemo {
@Test
void reportSingleValue(TestReporter testReporter) {
testReporter.publishEntry("a status message");
}
@Test
void reportKeyValuePair(TestReporter testReporter) {
testReporter.publishEntry("a key", "a value");
}
@Test
void reportMultipleKeyValuePairs(TestReporter testReporter) {
Map<String, String> values = new HashMap<>();
values.put("user name", "dk38");
values.put("award year", "1974");
testReporter.publishEntry(values);
}
}
传自定义参数
除了内置解析器,如果想传自定义参数,那么需要使用@ExtendWith
注册扩展,比如:
@ExtendWith(RandomParametersExtension.class)
class MyRandomParametersTest {
@Test
void injectsInteger(@Random int i, @Random int j) {
assertNotEquals(i, j);
}
@Test
void injectsDouble(@Random double d) {
assertEquals(0.0, d, 1.0);
}
}
有点插件的意思,更常见的是MockitoExtension和SpringExtension。
测试接口
JUnit Jupiter除了测试类和测试方法,其实也有测试接口,比如:
@TestInstance(Lifecycle.PER_CLASS)
interface TestLifecycleLogger {
static final Logger logger = Logger.getLogger(TestLifecycleLogger.class.getName());
@BeforeAll
default void beforeAllTests() {
logger.info("Before all tests");
}
@AfterAll
default void afterAllTests() {
logger.info("After all tests");
}
@BeforeEach
default void beforeEachTest(TestInfo testInfo) {
logger.info(() -> String.format("About to execute [%s]",
testInfo.getDisplayName()));
}
@AfterEach
default void afterEachTest(TestInfo testInfo) {
logger.info(() -> String.format("Finished executing [%s]",
testInfo.getDisplayName()));
}
}
interface TestInterfaceDynamicTestsDemo {
@TestFactory
default Stream<DynamicTest> dynamicTestsForPalindromes() {
return Stream.of("racecar", "radar", "mom", "dad")
.map(text -> dynamicTest(text, () -> assertTrue(isPalindrome(text))));
}
}
@Test
, @RepeatedTest
, @ParameterizedTest
, @TestFactory
, @TestTemplate
, @BeforeEach
, and @AfterEach
能作用到接口的default
方法上。
default
方法是接口已经实现好了的方法,接口的实现类不需要再编写实现代码,就能直接使用。
如果测试类是@TestInstance(Lifecycle.PER_CLASS)
注解,那么可以使用@BeforeAll
and @AfterAll
。
测试接口可以作为模版。如果测试接口有@ExtendWith
and @Tag
注解,那么它的实现类也会继承tags and extensions。比如:
@Tag("timed")
@ExtendWith(TimingExtension.class)
interface TimeExecutionLogger {
}
class TestInterfaceDemo implements TestLifecycleLogger,
TimeExecutionLogger, TestInterfaceDynamicTestsDemo {
@Test
void isEqualValue() {
assertEquals(1, "a".length(), "is always equal");
}
}
结果:
INFO example.TestLifecycleLogger - Before all tests
INFO example.TestLifecycleLogger - About to execute [dynamicTestsForPalindromes()]
INFO example.TimingExtension - Method [dynamicTestsForPalindromes] took 19 ms.
INFO example.TestLifecycleLogger - Finished executing [dynamicTestsForPalindromes()]
INFO example.TestLifecycleLogger - About to execute [isEqualValue()]
INFO example.TimingExtension - Method [isEqualValue] took 1 ms.
INFO example.TestLifecycleLogger - Finished executing [isEqualValue()]
INFO example.TestLifecycleLogger - After all tests
测试接口也可以作为契约。比如:
public interface Testable<T> {
T createValue();
}
public interface EqualsContract<T> extends Testable<T> {
T createNotEqualValue();
@Test
default void valueEqualsItself() {
T value = createValue();
assertEquals(value, value);
}
@Test
default void valueDoesNotEqualNull() {
T value = createValue();
assertFalse(value.equals(null));
}
@Test
default void valueDoesNotEqualDifferentValue() {
T value = createValue();
T differentValue = createNotEqualValue();
assertNotEquals(value, differentValue);
assertNotEquals(differentValue, value);
}
}
public interface ComparableContract<T extends Comparable<T>> extends Testable<T> {
T createSmallerValue();
@Test
default void returnsZeroWhenComparedToItself() {
T value = createValue();
assertEquals(0, value.compareTo(value));
}
@Test
default void returnsPositiveNumberWhenComparedToSmallerValue() {
T value = createValue();
T smallerValue = createSmallerValue();
assertTrue(value.compareTo(smallerValue) > 0);
}
@Test
default void returnsNegativeNumberWhenComparedToLargerValue() {
T value = createValue();
T smallerValue = createSmallerValue();
assertTrue(smallerValue.compareTo(value) < 0);
}
}
实现类:
class StringTests implements ComparableContract<String>, EqualsContract<String> {
@Override
public String createValue() {
return "banana";
}
@Override
public String createSmallerValue() {
return "apple"; // 'a' < 'b' in "banana"
}
@Override
public String createNotEqualValue() {
return "cherry";
}
}
小结
本文先介绍了JUnit Jupiter的颠覆性技术,允许传参以实现依赖注入,然后介绍了除了测试类和测试方法以外的测试接口,它既可以作为测试模板,也可以作为测试契约。
参考资料:
https://junit.org/junit5/docs/current/user-guide/#writing-tests-dependency-injection
https://junit.org/junit5/docs/current/user-guide/#writing-tests-test-interfaces-and-default-methods
标签:testInfo,TestInfo,default,void,value,接口,测试,Test,JUnit5 来源: https://www.cnblogs.com/df888/p/15025309.html