How to assert that Set has item with exact property with hamcrest

Question

i've been trying assert that my Set has collection with given property with hamcrest, using this solution, but i have :

java.lang.NoSuchMethodError: org.hamcrest.Matcher.describeMismatch(Ljava/lang/Object;Lorg/hamcrest/Description;)V at org.hamcrest.Condition$Matched.matching(Condition.java:52)

imports:

import static org.hamcrest.Matchers.contains;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.hasProperty;
import static org.junit.Assert.assertThat;

code:

assertThat(mySet, contains(hasProperty("id", equalTo("expectedId"))));

have You any ideas how to assert it well ?

Pothook

Answer 1

Well, you should try to let assertThat do the work for you.

Set<WhateverPropertyTypeYouAreUsing> expectedSet = Collections.singleton( ... create a property object with that id/value);

assertThat(mySet, is(expectedSet))

The restriction here: that assumes that your set contains only that one property value.

Otherwise, you can go for:

assertThat(mySet.contains(someProperty), is(true))

(probably with an additional message to better describe a failing assert).

Prereq: your property class should be implementing equals() in a reasonable manner.

Mahratta

i tought it won't work if I just initiate te same object in test and assert it's in my returned collection, because I tought it would compare if its the same object, if You know what I mean , but well, it works assertThat(mySet.contains(expectedValue), equalTo(true)); thank You :) – Pothook

Answer 2

Another approach will be:

assertTrue(mySet.contains(someProperty);

Symbiosis

Answer 3

Your original code is fine. Your problem is probably due to some version conflict. By the way, you should be using Hamcrest's assertThat (import static org.hamcrest.MatcherAssert.assertThat), instead of JUnit's.

Primero