1 package org.hamcrest.core; 2 3 import org.hamcrest.Matcher; 4 import org.junit.Test; 5 6 import static org.hamcrest.AbstractMatcherTest.*; 7 import static org.hamcrest.core.IsNull.notNullValue; 8 import static org.hamcrest.core.IsNull.nullValue; 9 10 11 public final class IsNullTest { 12 13 private final Matcher<Object> nullMatcher = nullValue(); 14 private final Matcher<Object> notNullMatcher = notNullValue(); 15 16 @Test public void copesWithNullsAndUnknownTypes()17 copesWithNullsAndUnknownTypes() { 18 assertNullSafe(nullMatcher); 19 assertUnknownTypeSafe(nullMatcher); 20 21 assertNullSafe(notNullMatcher); 22 assertUnknownTypeSafe(notNullMatcher); 23 } 24 25 @Test public void evaluatesToTrueIfArgumentIsNull()26 evaluatesToTrueIfArgumentIsNull() { 27 assertMatches(nullMatcher, null); 28 assertDoesNotMatch(nullMatcher, new Object()); 29 30 assertMatches(notNullMatcher, new Object()); 31 assertDoesNotMatch(notNullMatcher, null); 32 } 33 34 @Test public void supportsStaticTyping()35 supportsStaticTyping() { 36 requiresStringMatcher(nullValue(String.class)); 37 requiresStringMatcher(notNullValue(String.class)); 38 } 39 requiresStringMatcher(@uppressWarnings"unused") Matcher<String> arg)40 private void requiresStringMatcher(@SuppressWarnings("unused") Matcher<String> arg) { 41 // no-op 42 } 43 } 44