ExceptionalFunctionsTest.java

// =================================================================================================
// Copyright 2011 Twitter, Inc.
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or 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.twitter.common.base;

import java.io.IOException;

import org.easymock.EasyMock;
import org.easymock.IMocksControl;
import org.junit.Before;
import org.junit.Test;

import static org.easymock.EasyMock.expect;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertSame;

/**
 * @author John Sirois
 */
public class ExceptionalFunctionsTest {

  private static final String STRING = "jake";

  private IMocksControl control;
  private ExceptionalFunction<String, Integer, IOException> function;

  @Before public void setUp() throws Exception {
    control = EasyMock.createControl();

    @SuppressWarnings("unchecked")
    ExceptionalFunction<String, Integer, IOException> f =
        control.createMock(ExceptionalFunction.class);
    this.function = f;
  }

  @Test
  public void testCurryLazy() throws IOException {
    control.replay();

    ExceptionalFunctions.curry(function, STRING);

    control.verify();
  }

  @Test
  public void testCurryExecution() throws IOException {
    expect(function.apply(STRING)).andReturn(1);
    expect(function.apply(STRING)).andReturn(2);

    control.replay();

    CallableExceptionalSupplier<Integer, IOException> supplier =
        ExceptionalFunctions.curry(function, STRING);

    assertEquals("curried function should be called", Integer.valueOf(1), supplier.get());
    assertEquals("curried function should not be memoized", Integer.valueOf(2), supplier.get());

    control.verify();
  }

  @Test
  public void testCurryException() throws IOException {
    IOException ioException = new IOException();
    expect(function.apply(STRING)).andThrow(ioException);

    RuntimeException runtimeException = new IllegalStateException();
    expect(function.apply(STRING)).andThrow(runtimeException);

    control.replay();

    CallableExceptionalSupplier<Integer, IOException> supplier =
        ExceptionalFunctions.curry(function, STRING);

    try {
      supplier.get();
    } catch (IOException e) {
      assertSame("Expected exception propagation to be transparent", ioException, e);
    }

    try {
      supplier.get();
    } catch (IllegalStateException e) {
      assertSame("Expected exception propagation to be transparent", runtimeException, e);
    }

    control.verify();
  }
}