AbstractMemberProviderTest.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
 *
 *      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 org.apache.tomcat.cloud;

import org.apache.catalina.tribes.Member;
import org.junit.jupiter.api.Assumptions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.util.Collections;
import java.util.List;
import java.util.Properties;

import static org.junit.jupiter.api.Assertions.*;

class AbstractMemberProviderTest {

    private ConcreteProvider provider;

    @BeforeEach
    void setUp() {
        provider = new ConcreteProvider();
    }

    // -------------------------------------------------------------------------
    // constructor
    // -------------------------------------------------------------------------

    @Test
    void constructor_initializesMd5() {
        // MD5 is guaranteed by the Java Security specification on all compliant JVMs.
        // If the algorithm were unavailable the field would silently remain null, which
        // would cause a NullPointerException the first time digest() is called in a subclass.
        assertNotNull(provider.md5, "md5 digest should be initialized in constructor");
    }

    // -------------------------------------------------------------------------
    // getEnv()
    // -------------------------------------------------------------------------

    @Test
    void getEnv_returnsNullWhenKeyNotFound() {
        assertNull(provider.getEnvForTest("THIS_ENV_KEY_DOES_NOT_EXIST_12345"));
    }

    @Test
    void getEnv_returnsNullWhenAllKeysMissing() {
        assertNull(provider.getEnvForTest("FAKE_KEY_AAA_99999", "FAKE_KEY_BBB_99999"));
    }

    @Test
    void getEnv_noKeys_returnsNull() {
        // Calling getEnv() with an empty varargs array must return null because the loop
        // body never executes.
        assertNull(provider.getEnvForTest());
    }

    @Test
    void getEnv_nullKey_throwsNullPointerException() {
        // System.getenv(null) throws NullPointerException per the Java specification.
        // A null element in the keys array propagates that exception to the caller.
        // This documents that null keys are not supported; callers must ensure all keys
        // are non-null.
        assertThrows(NullPointerException.class,
                () -> provider.getEnvForTest((String) null));
    }

    @Test
    void getEnv_returnsFirstNonNullValue() {
        String pathValue = System.getenv("PATH");
        Assumptions.assumeTrue(pathValue != null, "PATH env var not available, skipping");

        String result = provider.getEnvForTest("THIS_KEY_DOES_NOT_EXIST", "PATH");
        assertEquals(pathValue, result, "Should skip missing keys and return the first found value");
    }

    @Test
    void getEnv_stopsAtFirstFoundKey() {
        String pathValue = System.getenv("PATH");
        Assumptions.assumeTrue(pathValue != null, "PATH env var not available, skipping");

        String result = provider.getEnvForTest("PATH", "THIS_KEY_DOES_NOT_EXIST");
        assertEquals(pathValue, result, "Should return immediately when the first key is found");
    }

    // -------------------------------------------------------------------------
    // Helper: concrete subclass to expose protected members for testing
    // -------------------------------------------------------------------------

    private static class ConcreteProvider extends AbstractMemberProvider {

        String getEnvForTest(String... keys) {
            return getEnv(keys);
        }

        @Override
        public void init(Properties properties) throws Exception {}

        @Override
        public List<? extends Member> getMembers() throws Exception {
            return Collections.emptyList();
        }
    }
}