java 如何使用 Hamcrest 验证地图大小
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How to verify Map size using Hamcrest
提问by Ramesh
Map<Integer, Map<String, String>> mapMap = new HashMap<Integer,Map<String, String>>();
Currently asserting like this
目前这样断言
assertThat(mapMap.size(), is(equalTo(1)));
Or
assertThat(mapMap.values(), hasSize(1));
Are there any other methods like one used with Lists.
是否有任何其他方法，例如与 Lists 一起使用的方法。
assertThat(someListReferenceVariable, hasSize(1));
assertThat(someListReferenceVariable, hasSize(1));
回答by eee
The good news
好消息
There is a matcher that does exactly what you want in the current master branch of the JavaHamcrest project. You can call it like so:
有一个匹配器可以在 JavaHamcrest 项目的当前主分支中执行您想要的操作。你可以这样称呼它：
assertThat(mapMap, aMapWithSize(1));
And the bad news
还有坏消息
Unfortunately this matcher is not in the latest release of Hamcrest (1.3).
不幸的是，这个匹配器不在最新版本的 Hamcrest (1.3) 中。
[Update] And finally the very good news
[更新] 最后一个好消息
The aforementioned matcher is includedin the newly released version 2.1.
在上述匹配包括在新发布的2.1版本。
回答by Ruben
There is none in Hamcrest 1.3, but you can very easily create your own:
Hamcrest 1.3 中没有，但您可以非常轻松地创建自己的：
public class IsMapWithSize<K, V> extends FeatureMatcher<Map<? extends K, ? extends V>, Integer> {
public IsMapWithSize(Matcher<? super Integer> sizeMatcher) {
super(sizeMatcher, "a map with size", "map size");
}
@Override
protected Integer featureValueOf(Map<? extends K, ? extends V> actual) {
return actual.size();
}
/**
* Creates a matcher for {@link java.util.Map}s that matches when the
* <code>size()</code> method returns a value that satisfies the specified
* matcher.
* <p/>
* For example:
*
* <pre>
* Map<String, Integer> map = new HashMap<>();
* map.put("key", 1);
* assertThat(map, isMapWithSize(equalTo(1)));
* </pre>
*
* @param sizeMatcher
* a matcher for the size of an examined {@link java.util.Map}
*/
@Factory
public static <K, V> Matcher<Map<? extends K, ? extends V>> isMapWithSize(Matcher<? super Integer> sizeMatcher) {
return new IsMapWithSize<K, V>(sizeMatcher);
}
/**
* Creates a matcher for {@link java.util.Map}s that matches when the
* <code>size()</code> method returns a value equal to the specified
* <code>size</code>.
* <p/>
* For example:
*
* <pre>
* Map<String, Integer> map = new HashMap<>();
* map.put("key", 1);
* assertThat(map, isMapWithSize(1));
* </pre>
*
* @param size
* the expected size of an examined {@link java.util.Map}
*/
@Factory
public static <K, V> Matcher<Map<? extends K, ? extends V>> isMapWithSize(int size) {
Matcher<? super Integer> matcher = equalTo(size);
return IsMapWithSize.<K, V> isMapWithSize(matcher);
}
}
Testing:
测试：
Map<String, Integer> map = new HashMap<>();
map.put("key", 1);
assertThat(map, isMapWithSize(1));
assertThat(map, isMapWithSize(equalTo(1)));
回答by Declow0
You can check this using not and any
您可以使用 not 和 any 进行检查
import static org.hamcrest.Matchers.any;
import static org.hamcrest.Matchers.hasEntry;
import static org.hamcrest.Matchers.not;
not(hasEntry(any(Object.class), any(Object.class)))
