/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.documentsui.testing;

import static junit.framework.Assert.assertFalse;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import com.android.documentsui.base.EventHandler;

import javax.annotation.Nullable;

/**
 * Test {@link EventHandler} that can be used to spy on,  control responses from,
 * and make assertions against values tested.
 */
public class TestEventHandler<T> implements EventHandler<T> {

    private @Nullable T lastValue;
    private boolean nextReturnValue;
    private boolean called;

    @Override
    public boolean accept(T event) {
        called = true;
        lastValue = event;
        return nextReturnValue;
    }

    public void assertLastArgument(@Nullable T expected) {
        assertEquals(expected, lastValue);
    }

    public void assertCalled() {
        assertTrue(called);
    }

    public void assertNotCalled() {
        assertFalse(called);
    }

    public void nextReturn(boolean value) {
        nextReturnValue = value;
    }

    public @Nullable T getLastValue() {
        return lastValue;
    }

    public void reset() {
        called = false;
        lastValue = null;
        nextReturnValue = false;
    }
}