src/test/java/org/apache/commons/configuration2/TestConfigurationLookup.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *     https://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 org.apache.commons.configuration2;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertIterableEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.junit.jupiter.api.Test;

/**
 * Test class for {@code ConfigurationLookup}.
 */
public class TestConfigurationLookup {

    /** Constant for a test variable name. */
    private static final String VAR = "testVariable";

    /** Constant for the value of the test variable. */
    private static final Object VALUE = "SomeTestValue";

    /**
     * Tries to create an instance without a configuration.
     */
    @Test
    void testInitNoConfig() {
        assertThrows(IllegalArgumentException.class, () -> new ConfigurationLookup(null));
    }

    /**
     * Tests lookup() for a complex property value.
     */
    @Test
    void testLookupComplex() {
        final int count = 5;
        final Configuration conf = new BaseConfiguration();
        for (int i = 0; i < count; i++) {
            conf.addProperty(VAR, String.valueOf(VALUE) + i);
        }
        final ConfigurationLookup lookup = new ConfigurationLookup(conf);
        final Collection<?> col = (Collection<?>) lookup.lookup(VAR);

        final List<String> expected = new ArrayList<>();
        for (int i = 0; i < count; i++) {
            expected.add(String.valueOf(VALUE) + i);
        }
        assertIterableEquals(expected, col);
    }

    /**
     * Tests lookup() if the variable cannot be resolved.
     */
    @Test
    void testLookupNotFound() {
        final Configuration conf = new BaseConfiguration();
        final ConfigurationLookup lookup = new ConfigurationLookup(conf);
        assertNull(lookup.lookup(VAR));
    }

    /**
     * Tests lookup() if the variable cannot be resolved, and the configuration throws an exception.
     */
    @Test
    void testLookupNotFoundEx() {
        final BaseConfiguration conf = new BaseConfiguration();
        conf.setThrowExceptionOnMissing(true);
        final ConfigurationLookup lookup = new ConfigurationLookup(conf);
        assertNull(lookup.lookup(VAR));
    }

    /**
     * Tests whether an existing variable can be resolved.
     */
    @Test
    void testLookupSuccess() {
        final Configuration conf = new BaseConfiguration();
        conf.addProperty(VAR, VALUE);
        final ConfigurationLookup lookup = new ConfigurationLookup(conf);
        assertEquals(VALUE, lookup.lookup(VAR));
    }
}