How to use getAnnotations method of org.junit.runners.model.Interface Annotatable class

I had the exact same issue on Android Studio and solved it by updating the Kotlin Gradle plugin from version 1.4.31 to version 1.5.30.

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.30"

In my project-level build.gradle file.

You can cast the array to a list:

assertTrue(Arrays.asList(yourArray).contains(yourElement));

Access MainConfig.xml directly. The src/test/resources directory contents are placed in the root of your CLASSPATH.

More precisely: contents of src/test/resources are copied into target/test-classes, so if you have the following project structure:

.
└── src
    └── test
        ├── java
        │   └── foo
        │       └── C.java
        └── resources
            ├── a.xml
            └── foo
                └── b.xml

It will result with the following test CLASSPATH contents:

• /foo/C.class
• /a.xml
• /foo/b.xml

To actually access the files from Java source, use getClass().getResource("/MainConfig.xml").getFile().

I think the docs provide a useful summary:

If you would prefer that JUnit Jupiter execute all test methods on the same test instance, simply annotate your test class with @TestInstance(Lifecycle.PER_CLASS). When using this mode, a new test instance will be created once per test class. Thus, if your test methods rely on state stored in instance variables, you may need to reset that state in @BeforeEach or @AfterEach methods.

The "per-class" mode has some additional benefits over the default "per-method" mode. Specifically, with the "per-class" mode it becomes possible to declare @BeforeAll and @AfterAll on non-static methods as well as on interface default methods. The "per-class" mode therefore also makes it possible to use @BeforeAll and @AfterAll methods in @Nested test classes.

But you've probably read that already and you are correct in thinking that making a field static will have the same effect as declaring the field as an instance variable and using @TestInstance(Lifecycle.PER_CLASS).

So, perhaps the answer to the question "how it could be useful in JUnit 5" is that using a @TestInstance ...

• Is explicit about your intentions. It could be assumed that use of the static keyword was accidental whereas use of @TestInstance is less likely to be accidental or a result of thoughless copy-n-paste.
• Delegates the responsibility for managing scope and lifecycle and clean up to the framework rather than having to remember to manage that yourself.

Failures are when your test cases fail – i.e. your assertions are incorrect.

Errors are when unexpected errors/exceptions occur - i.e. while trying to actually run the test and an unexpected exception is thrown like FileNotFound, etc`.

Let me quote the official documentation:

Important gotcha on spying real objects!

Sometimes it's impossible to use when(Object) for stubbing spies. Example:

List list = new LinkedList();
List spy = spy(list);

// Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty)
when(spy.get(0)).thenReturn("foo");

// You have to use doReturn() for stubbing
doReturn("foo").when(spy).get(0);

In your case it goes something like:

doReturn(resultsIWant).when(myClassSpy).method1();

You should always use .equals() when comparing Strings in Java.

JUnit calls the .equals() method to determine equality in the method assertEquals(Object o1, Object o2).

So, you are definitely safe using assertEquals(string1, string2). (Because Strings are Objects)

Here is a link to a great Stackoverflow question regarding some of the differences between == and .equals().

It depends on the JUnit version and what assert libraries you use.

• For JUnit5 and 4.13 see answer
• If you use AssertJ or google-truth, see answer

The original answer for JUnit <= 4.12 was:

    @Test(expected = IndexOutOfBoundsException.class)
    public void testIndexOutOfBoundsException() {

        ArrayList emptyList = new ArrayList();
        Object o = emptyList.get(0);

    }

Though answer has more options for JUnit <= 4.12.

Reference:

• JUnit Test-FAQ

There are libraries that help with this:

Apache commons-lang

If you have Apache commons-lang on your classpath, you can use DateUtils.truncate to truncate the dates to some field.

assertEquals(DateUtils.truncate(date1,Calendar.SECOND),
             DateUtils.truncate(date2,Calendar.SECOND));

There is a shorthand for this:

assertTrue(DateUtils.truncatedEquals(date1,date2,Calendar.SECOND));

Note that 12:00:00.001 and 11:59:00.999 would truncate to different values, so this might not be ideal. For that, there is round:

assertEquals(DateUtils.round(date1,Calendar.SECOND),
             DateUtils.round(date2,Calendar.SECOND));

AssertJ

Starting with version 3.7.0, AssertJ added an isCloseTo assertions, if you are using the Java 8 Date / Time API.

LocalTime _07_10 = LocalTime.of(7, 10);
LocalTime _07_42 = LocalTime.of(7, 42);
assertThat(_07_10).isCloseTo(_07_42, within(1, ChronoUnit.HOURS));
assertThat(_07_10).isCloseTo(_07_42, within(32, ChronoUnit.MINUTES));

It also works with legacy java Dates as well:

Date d1 = new Date();
Date d2 = new Date();
assertThat(d1).isCloseTo(d2, within(100, ChronoUnit.MILLIS).getValue());