Asserting Guice Servlet Module Binding

gistfile1.java

    @VisibleForTesting
    Injector createInjector() {
        return Guice.createInjector(new ServletModule() {
            @Override
            protected void configureServlets() {
                serve("/img/*").with(ImageFooServlet.class);
                serve("/rd/*").with(RedirectFooServlet.class);
            }
        });
    }

GuiceServletConfigTest.java

import static com.netflix.beacon.server.ServletModuleAssert.assertBindingToPattern;

import org.junit.Test;

import com.google.inject.Injector;

public class GuiceServletConfigTest {

    @Test
    public void testBinding() {
        Injector injector = new GuiceServletConfig().createInjector();
        assertBindingToPattern(injector, ImageFooServlet.class, "/img/*");
    }

}

ServletModuleAssert.java

import static java.lang.String.format;
import static org.junit.Assert.fail;

import javax.servlet.http.HttpServlet;

import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.servlet.InstanceFilterBinding;
import com.google.inject.servlet.InstanceServletBinding;
import com.google.inject.servlet.LinkedFilterBinding;
import com.google.inject.servlet.LinkedServletBinding;
import com.google.inject.servlet.ServletModuleTargetVisitor;
import com.google.inject.spi.DefaultBindingTargetVisitor;

public class ServletModuleAssert {

    public static void assertBindingToPattern(Injector injector,
            Class<? extends HttpServlet> clazz, String pattern) {
        for (Binding<?> binding: injector.getAllBindings().values()) {
            Visitor visitor = new Visitor(clazz);
            if (binding.acceptTargetVisitor(visitor)) {
                if (!pattern.equals(visitor.pattern)) {
                    fail(format("expected pattern for clazz %s is [%s], actual is [%s]",
                            clazz, pattern, visitor.pattern));
                }
                return;
            }
        }
        fail(format("no binding for clazz %s", pattern));
    }

    private static class Visitor extends
            DefaultBindingTargetVisitor<Object, Boolean> implements
            ServletModuleTargetVisitor<Object, Boolean> {
        private final Class<? extends HttpServlet> clazz;
        private String pattern;

        Visitor(Class<? extends HttpServlet> clazz) {
            this.clazz = clazz;
        }

        @Override
        public Boolean visit(LinkedFilterBinding binding) {
            return false;
        }

        @Override
        public Boolean visit(InstanceFilterBinding binding) {
            return false;
        }

        @Override
        public Boolean visit(LinkedServletBinding binding) {
            if (clazz.equals(binding.getLinkedKey().getTypeLiteral().getRawType())) {
                pattern = binding.getPattern();
                return true;
            }
            return false;
        }

        @Override
        public Boolean visit(InstanceServletBinding binding) {
            if (clazz.equals(binding.getServletInstance().getClass())) {
                pattern = binding.getPattern();
                return true;
            }
            return false;
        }

        @Override
        protected Boolean visitOther(Binding<? extends Object> binding) {
            return false;
        }
    }

}

nice. thx!