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?

Joachim Sauer · Accepted Answer · 2020-08-27T12:20:00.730

69

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

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

edited Aug 27 '20 at 12:20

answered May 17 '11 at 09:30

Joachim Sauer

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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 May 17 '11 at 13:37
Not for me...I just see assertTrue – Alex May 17 '11 at 13:43
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@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. – Joachim Sauer May 17 '11 at 13:47
You missed one ')' at the end of `assertThat` statement. – JiaHao Xu Aug 27 '20 at 11:21
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@JiaHaoXu: indeed, fixed now. Note that you can edit (or suggest an edit) the answer yourself for typos like this. – Joachim Sauer Aug 27 '20 at 12:20
Please add the relevant import statements to the example, to make it more clear. – Thomas Schütt Jul 09 '21 at 09:43

Jonathan · Answer 2 · 2021-08-03T10:41:04.283

34

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.

edited Aug 03 '21 at 10:41

answered Jul 05 '13 at 08:55

Jonathan

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score 16 · Answer 3 · answered Apr 05 '16 at 05:02

16

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

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

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

answered Apr 05 '16 at 05:02

Barun Kumar

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for who use junit Assert `String expectedTitles[] = {"In-Progress","Completed"};` `List expectedTitlesList = Arrays.asList(expectedTitles);` `Assert.assertTrue(expectedTitlesList.contains((transferRequest.getRequestStatus())));` – Extreme Jun 25 '17 at 21:58
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For those who is forced to use junit 3 this is a good solution. – sergeyan Nov 26 '19 at 13:21

alpian · Answer 4 · 2016-08-17T21:51:46.017

7

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.)

edited Aug 17 '16 at 21:51

answered May 17 '11 at 09:32

alpian

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Please add the relevant import statements to the example, to make it more clear. – Thomas Schütt Jul 09 '21 at 09:42

fglez · Answer 5 · 2017-08-01T22:14:42.247

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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)
[...]

edited Aug 01 '17 at 22:14

answered Aug 01 '17 at 22:08

fglez

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What import statement do you have for isOneOf? What JUnit version? – Paulo Merson Aug 24 '18 at 18:07
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JUnit 4 using Hamcrest 1.3 - http://hamcrest.org/JavaHamcrest/javadoc/1.3/org/hamcrest/Matchers.html#isOneOf(T...) – fglez Aug 27 '18 at 07:39
Deprecated: use is(oneOf(...)) instead. – Jacob van Lingen Mar 30 '21 at 07:50

score 4 · Answer 6 · answered May 17 '11 at 09:23

4

If your using junit I'd just do something like the following:

assertTrue(myString.equals("Value1") || myString.equals("Value"));

answered May 17 '11 at 09:23

Tom Jefferys

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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 Mar 16 '18 at 17:43

score 2 · Answer 7 · edited Jul 05 '13 at 08:56

2

Consider writing a custom hamcrest matcher returned by a method, in this case containsOneOf, i.e.:

assertThat(myString, containsOneOf("value1", "value2"));

In keeping with the "xUnit patterns" you should avoid conditional logic in your matcher, a loop with a break statement should suffice.

Have a look at Hamcrest and xUnit Patterns for more information.

edited Jul 05 '13 at 08:56

Jonathan

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answered May 17 '11 at 09:37

murungu

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score 1 · Answer 8 · answered Aug 07 '18 at 01:40

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I think you can just use assertTrue:

assertTrue(testString.matches("string1|string2"));

answered Aug 07 '18 at 01:40

OSrookie

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joe776 · Answer 9 · 2011-05-17T09:29:11.303

If the content for a line is fixed you can split it at line endings before comparing. Then simply compare each line to a set of expected values. Something like this:

   Set<String> expectedValues = ...
   String[] split = text.split("\n");
   for(String str : split) {
      assert(expectedValues.contains(str));
   }

If you want to check that all expected values are present you can assert that expectedValue.remove(str) == true and assert after the loop that the Set is empty. If some lines may occur multiple times you have to use a Bag instead of a Set.

score 1 · Answer 10 · answered May 17 '11 at 09:43

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The simplest/most efficient might be

assert str.equals(result1) || str.equals(result2);

This will effectively have no overhead when you don't have assertions turned on.

answered May 17 '11 at 09:43

Peter Lawrey

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but in Android studio, I am finding that asserts are not evaluated in my instrumented tests. I need to use assertTrue instead – likejudo Aug 26 '16 at 17:28
@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. – Peter Lawrey Aug 26 '16 at 22:21
`assert.assertequals(expected, actual)` doesn't allow `||` operator – Sanchit Mar 07 '18 at 05:10
@Sanchit assetTrue does. – Peter Lawrey Mar 07 '18 at 23:26
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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" – Franz See Mar 16 '18 at 17:45

score 0 · Answer 11 · answered Jan 01 '15 at 09:06

Assuming the method under test returns an array, you could test using Hamcrest's arrayContainingInAnyOrder.

assertThat(result, is(arrayContainingInAnyOrder("value1", "value2", "value")))

Note: use of is wrapper is purely optional, used only as readability sugar.

score 0 · Answer 12 · answered Mar 02 '22 at 12:30

0

Simple solution using AssertTrue.
Just create a List.of() the expected values and check is it contains the expected value.

assertTrue(List.of("expected_1", "expected_2").contains("actual))

answered Mar 02 '22 at 12:30

Neel Alex

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score 0 · Answer 13 · answered Apr 21 '22 at 17:01

If you do not have or can't use third-party libraries except junit core, you can use this small helper method:

public static void assertListContains(List<Object> expected, Object actual) {
    if (!expected.contains(actual)) {
        fail("Expected: " + expected + " Actual: " + actual);
    }
}

Advantage, in contrast to other workaround answers, is that you can see what was expected and what was actual:

org.opentest4j.AssertionFailedError: Expected: [1, 2] Actual: 3

score -1 · Answer 14 · answered Aug 03 '18 at 08:33

It's an old post, but I wanted to have an native easy answer, without having extra libraries to add. :)

So I did :

String e
e = "ear"
j = "jars"

assert (j == "jar" || e == "ear")

or if you want them to be both true

assert (j == "jar" && e == "ear")

score -1 · Answer 15 · answered Aug 28 '20 at 15:17

-1

This seems to me like the simplest solution ...

assert obtainedValue in [acceptedValue1, acceptedValue2]

answered Aug 28 '20 at 15:17

Albion

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

15 Answers15