How to assert an actual value against 2 or more expected values?

Question

I'm testing a method to see if it returns the correct string. This string is made up of a lot of lines whose order might change, thus usually giving 2 possible combinations. That order is not important for my application.

However, because the order of the lines might change, writing just an Assert statement will not work, since sometimes it will pass the test, and sometimes it will fail the test.

So, is it possible to write a test that will assert an actual string value against 2 or more expected string values and see if it is equal to any of them?

Solution 1

Using the Hamcrest CoreMatcher (included in JUnit 4.4 and later) and assertThat():

assertThat(myString, anyOf(is("value1"), is("value2")));

Solution 2

I would use AssertJ for this:

import static org.assertj.core.api.Assertions.*;

assertThat("hello").isIn("hello", "world");

It's more concise and it will give you a descriptive message when the assertion fails.

Solution 3

I am using the following, I hope this would help:

String expectedTitles[] = {"Expected1","Expected2"};
List<String> expectedTitlesList = Arrays.asList(expectedTitles);

assertTrue(expectedTitlesList.contains((actualTitle)));

Solution 4

You can use Hamcrest for this:

assertThat(testString, anyOf(
    containsString("My first string"), 
    containsString("My other string")));

(I see Joachim just answered very similarly (+1)... i'll add this as another example.)

Solution 5

I read all answers, but the one that seems most compact and expressive to me is using Hamcrest's isOneOf which is already included in JUnit

assertThat(result, isOneOf("value1", "value2"));

which gives you a nice error message when failing.

java.lang.AssertionError: 
Expected: one of {"value1", "value2"}
     but: was "value"
    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
[...]

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Comments

[Alex]

I managed to fix this eventually, but for some reason, for me, JUnit 4 doesn't have an 'assertThat' method in CoreMatcher. I ended up combining the main Hamcrest library with the JUnit library in order to get it to work.

[Alex]

Not for me...I just see assertTrue

[Joachim Sauer]

@Andrei: are you sure you checked org.junit.Assert and not junit.framework.Assert? The later only exist for backwards compatibility with JUnit 3 and doesn't support assertThat. In org.junit.Assert` was introduced in JUnit 4.4. So if you have an earlier version, it will be missing.

[likejudo]

but in Android studio, I am finding that asserts are not evaluated in my instrumented tests. I need to use assertTrue instead

[Vishy]

@likejiujitsu you need to ensure -ea is a command line option. assertEquals is best for testing but only use assert in production so it can be turned off.

[Extreme]

for who use junit Assert String expectedTitles[] = {"In-Progress","Completed"}; List<String> expectedTitlesList = Arrays.asList(expectedTitles); Assert.assertTrue(expectedTitlesList.contains((transferReque‌​st.getRequestStatus(‌​))));

[Sanchit]

assert.assertequals(expected, actual) doesn't allow || operator

[Vishy]

@Sanchit assetTrue does.

[Franz See]

This is a bad practice in testing. Though logically, it will pass and fail when it's supposed to, the problem is that if it fails, you will not have a descriptive error message. instead, you will get something like "expected true but was false" which tells you nothing about the problem. But by using hamcrest matchers or assertj, you will get something like this on failure : expected to be one of the following : "Value1", "Value2" but was "XYZ"

[Franz See]

But this will not show you any meaningful error message when it fails. Using hamcrest or assertj provides you with something like "expected values X, Y but was Z"

[Paulo Merson]

What import statement do you have for isOneOf? What JUnit version?

[fglez]

JUnit 4 using Hamcrest 1.3 - hamcrest.org/JavaHamcrest/javadoc/1.3/org/hamcrest/…

[sergeyan]

For those who is forced to use junit 3 this is a good solution.

[JiaHao Xu]

You missed one ')' at the end of assertThat statement.

[Joachim Sauer]

@JiaHaoXu: indeed, fixed now. Note that you can edit (or suggest an edit) the answer yourself for typos like this.

[Jacob van Lingen]

Deprecated: use is(oneOf(...)) instead.

[user2081279]

Please add the relevant import statements to the example, to make it more clear.

[user2081279]

Please add the relevant import statements to the example, to make it more clear.