Added a test for issue qos-ch#39 (missing configuration files).

pom.xml

@@ -90,6 +90,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
     <logback.version>1.1.1</logback.version>
+    <slf4j.version>1.7.6</slf4j.version>
 
     <!-- JDK properties that can be overridden from the command line
          to build under a different JDKs (continuous integration) -->

spring/pom.xml

@@ -72,6 +72,20 @@
       <optional>true</optional>
     </dependency>
 
+    <!-- Testing -->
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-test</artifactId>
+      <version>${spring.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>jcl-over-slf4j</artifactId>
+      <version>${slf4j.version}</version>
+      <scope>test</scope>
+    </dependency>
+
   </dependencies>
 
   <build>

spring/src/test/java/ch/qos/logback/ext/spring/MissingConfigurationTest.java

@@ -0,0 +1,145 @@
+/**
+ * Copyright (C) 2016 The MITRE Corporation
+ *
+ * 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 ch.qos.logback.ext.spring;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.UnsynchronizedAppenderBase;
+import ch.qos.logback.core.joran.spi.JoranException;
+import ch.qos.logback.ext.spring.web.WebLogbackConfigurer;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Random;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.slf4j.impl.StaticLoggerBinder;
+import org.springframework.mock.web.MockServletContext;
+
+/**
+ * Tests the behavior of the logging configuration if the configuration files are missing.
+ * @author John Gibson
+ */
+public class MissingConfigurationTest {
+    /**
+     * Parameter specifying the location of the logback config file
+     */
+    private static final String CONFIG_LOCATION_PARAM = "logbackConfigLocation";
+
+    private static Random rng = new Random();
+
+    @ClassRule
+    public static final TemporaryFolder PLAYGROUND = new TemporaryFolder();
+
+    @Before
+    public void clearFakeLogs() {
+        FakeAppender.logs.clear();
+    }
+
+    /**
+     * Aside from printing the test name this also ensures that the logging system is in the known default state.
+     */
+    @Rule
+    public TestRule ensureLoggingInitialized = new TestWatcher() {
+        @Override
+        protected void starting(Description description) {
+            Logger log = LoggerFactory.getLogger(MissingConfigurationTest.class);
+            log.info("Starting test: " + description.getMethodName());
+        }
+    };
+
+    @After
+    public void cleanupLogging() {
+        LoggerContext loggerContext = (LoggerContext) StaticLoggerBinder.getSingleton().getLoggerFactory();
+        loggerContext.reset();
+    }
+
+    @Test(timeout = 1000L)
+    public void testMissingConfiguration() throws Exception {
+        MockServletContext context = new MockServletContext();
+        File missingConfig = null;
+        do {
+            missingConfig = new File("missingConfigTest" + rng.nextInt() + ".xml");
+        } while (missingConfig.exists());
+
+        context.addInitParameter(CONFIG_LOCATION_PARAM, missingConfig.toURI().toURL().toString());
+
+        WebLogbackConfigurer.initLogging(context);
+    }
+
+    @Test
+    public void testInvalidConfiguration() throws Exception {
+        MockServletContext context = new MockServletContext();
+        File empty = PLAYGROUND.newFile("empty.xml");
+        context.addInitParameter(CONFIG_LOCATION_PARAM, empty.toURI().toURL().toString());
+        try {
+            WebLogbackConfigurer.initLogging(context);
+            fail("Error expected.");
+        } catch (RuntimeException e) {
+            assertEquals("Unexpected error while configuring logback", e.getMessage());
+            assertTrue("Expected a RuntimeException wrapping a JoranException, but it was a different cause: " + e.getCause(), e.getCause() instanceof JoranException);
+        }
+    }
+
+    @Test(timeout = 1000L)
+    public void testMissingFollowedByNormalConfiguration() throws Exception {
+        MockServletContext context = new MockServletContext();
+        File missingConfig = null;
+        do {
+            missingConfig = new File("missingConfigTest" + rng.nextInt() + ".xml");
+        } while (missingConfig.exists());
+
+        context.addInitParameter(CONFIG_LOCATION_PARAM, missingConfig.toURI().toURL().toString() + "," + getClass().getResource("fakeLogger.xml"));
+        WebLogbackConfigurer.initLogging(context);
+        Logger log = LoggerFactory.getLogger(MissingConfigurationTest.class);
+        String key = "missingConfig" + rng.nextInt();
+        log.error(key);
+        boolean found = false;
+        ArrayList<ILoggingEvent> logs;
+        synchronized (FakeAppender.class) {
+            logs = new ArrayList<ILoggingEvent>(FakeAppender.logs);
+        }
+        for (ILoggingEvent evt : logs) {
+            if (key.equals(evt.getMessage())) {
+                found = true;
+            }
+        }
+        assertTrue("Logging event was not found: " + logs, found);
+    }
+
+    public static class FakeAppender extends UnsynchronizedAppenderBase<ILoggingEvent> {
+        private static final ArrayList<ILoggingEvent> logs = new ArrayList<ILoggingEvent>();
+
+        @Override
+        protected void append(ILoggingEvent eventObject) {
+            synchronized(FakeAppender.class) {
+                logs.add(eventObject);
+            }
+        }
+    }
+}

spring/src/test/resources/ch/qos/logback/ext/spring/fakeLogger.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2012 Ceki Gulcu, Les Hazlewood, et. al.
+  ~
+  ~ 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.
+  -->
+<configuration debug="true">
+
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg %throwable{5}%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="springTest" class="ch.qos.logback.ext.spring.MissingConfigurationTest$FakeAppender"/>
+    <root level="WARN">
+        <appender-ref ref="springTest"/>
+    </root>
+
+    <root level="warn">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>