MvpNullObjectBasePresenterTest.java

/*
 * Copyright 2017 Hannes Dorfmann.
 *
 * 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.hannesdorfmann.mosby3.mvp;

import com.hannesdorfmann.mosby3.mvp.test.data.TestData;
import com.hannesdorfmann.mosby3.mvp.test.presenter.ParameterlessConstructorMvpPresenter;
import com.hannesdorfmann.mosby3.mvp.test.presenter.SubMvpPresenter;
import com.hannesdorfmann.mosby3.mvp.test.presenter.SubParameterlessConstructorMvpPresenter;
import com.hannesdorfmann.mosby3.mvp.test.presenter.UselessGenericParamsMvpPresenter;
import com.hannesdorfmann.mosby3.mvp.test.view.SubMvpView;
import com.hannesdorfmann.mosby3.mvp.test.view.TestMvpView;
import com.hannesdorfmann.mosby3.mvp.test.view.TestMvpViewWithMultipleInterfaces;
import org.junit.Assert;
import org.junit.Test;

/**
 * @author Hannes Dorfmann
 */
public class MvpNullObjectBasePresenterTest {

  @Test public void throwsExceptionWhenInteractingWithPresenterButNoViewHasEverAttached() {

    MvpNullObjectBasePresenter<MvpView> presenter = new MvpNullObjectBasePresenter<MvpView>() {
    };

    try {
      presenter.getView();
      Assert.fail("Exception should be thrown");
    } catch (IllegalStateException e) {
      // Expected exception
    }
  }

  @Test @SuppressWarnings("unchecked") public void uselessGenericsParamsPresenter() {
    TestMvpView view = newTestView();
    UselessGenericParamsMvpPresenter presenter = new UselessGenericParamsMvpPresenter<>();

    testPickingCorrectViewInterface(presenter);
    testAttachDetachView(presenter, view);

    presenter.attachView(view);
    presenter.viewShowThat();
    presenter.detachView(false);
    presenter.viewShowThat();
  }

  @Test public void constructorGenericParameterless() {
    ParameterlessConstructorMvpPresenter<TestData> presenter =
        new ParameterlessConstructorMvpPresenter<>();
    TestMvpView view = newTestView();

    testPickingCorrectViewInterface(presenter);
    testAttachDetachView(presenter, view);

    presenter.attachView(view);
    presenter.viewShowThat();
    presenter.detachView(false);
    presenter.viewShowThat();
  }

  @Test public void constructorDirectlyBaseClass() {
    MvpNullObjectBasePresenter<TestMvpView> presenter =
        new MvpNullObjectBasePresenter<TestMvpView>() {
        };
    TestMvpView view = newTestView();

    testPickingCorrectViewInterface(presenter);
    testAttachDetachView(presenter, view);
  }

  @Test public void constructorSubClass() {
    SubParameterlessConstructorMvpPresenter presenter =
        new SubParameterlessConstructorMvpPresenter();
    TestMvpView view = newTestView();

    testPickingCorrectViewInterface(presenter);
    testAttachDetachView(presenter, view);

    presenter.attachView(view);
    presenter.viewShowThat();
    presenter.detachView(false);
    presenter.viewShowThat();
  }

  @Test public void subviewInterface() {
    SubMvpPresenter presenter = new SubMvpPresenter();
    SubMvpView view = newSubTestView();

    testAttachDetachView(presenter, view);

    presenter.attachView(view);
    presenter.invokeShowThat();
    presenter.detachView(false);
    presenter.invokeShowThat();
  }

  private <V extends MvpView> void testAttachDetachView(
      final MvpNullObjectBasePresenter<V> presenter, final V view) {

    testAttachView(presenter, view);
    testDetachNonRetain(presenter, view);
    testAttachView(presenter, view);
    testDetachRetain(presenter, view);
  }

  private <V extends MvpView> void testAttachView(final MvpNullObjectBasePresenter<V> presenter,
      final V view) {
    presenter.attachView(view);
    Assert.assertNotNull(presenter.getView());
    Assert.assertTrue(presenter.getView() == view);
  }

  private <V extends MvpView> void testDetachNonRetain(
      final MvpNullObjectBasePresenter<V> presenter, final V view) {
    presenter.detachView(false);
    Assert.assertNotNull(presenter.getView());
    Assert.assertTrue(presenter.getView() != view); // Null Object view;
  }

  private <V extends MvpView> void testDetachRetain(final MvpNullObjectBasePresenter<V> presenter,
      final V view) {
    presenter.detachView(true);
    Assert.assertNotNull(presenter.getView());
    Assert.assertTrue(presenter.getView() != view); // Null Object view;
  }

  private void testPickingCorrectViewInterface(
      final MvpNullObjectBasePresenter<TestMvpView> presenter) {
    TestMvpViewWithMultipleInterfaces view = new TestMvpViewWithMultipleInterfaces();

    presenter.attachView(view);
    Assert.assertNotNull(presenter.getView());
    Assert.assertTrue(view == presenter.getView());

    presenter.detachView(false);
    Assert.assertNotNull(presenter.getView());
    Assert.assertFalse(presenter.getView() == view);

    // Invoke methods on null object
    presenter.getView().showFoo(new TestData());
    presenter.getView().showThat();
  }

  private TestMvpView newTestView() {
    return new TestMvpView() {
      @Override public void showFoo(TestData data) {
      }

      @Override public void showThat() {
      }
    };
  }

  private SubMvpView newSubTestView() {
    return new SubMvpView() {
      @Override public void showFoo(TestData data) {
      }

      @Override public void showThat() {

      }
    };
  }
}