@Test
    public void testNullExpectedValueNull() {
        Matcher matcher = new HeaderMatcher(NAME, null);
        val context = MockWebContext.create();
        assertTrue(matcher.matches(new CallContext(context, new MockSessionStore())));
    }
Tests {@link HeaderMatcher}.

@author Jerome Leleu
@since 1.9.3
pac4j-core/src/test/java/org/pac4j/core/matching/matcher/HeaderMatcherTests.java