Github user jburwell commented on a diff in the pull request:
https://github.com/apache/cloudstack/pull/1331#discussion_r60742145
--- Diff:
services/secondary-storage/server/test/org/apache/cloudstack/storage/resource/TestAppender.java
---
@@ -0,0 +1,173 @@
+/*
+* 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.cloudstack.storage.resource;
+
+import com.google.common.base.Joiner;
+import com.google.common.base.Objects;
+import com.google.common.collect.ImmutableMap;
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.log4j.spi.LoggingEvent;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.regex.Pattern;
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.base.Strings.isNullOrEmpty;
+import static java.lang.String.format;
+import static org.apache.log4j.Level.ALL;
+import static org.apache.log4j.Level.DEBUG;
+import static org.apache.log4j.Level.ERROR;
+import static org.apache.log4j.Level.FATAL;
+import static org.apache.log4j.Level.INFO;
+import static org.apache.log4j.Level.OFF;
+import static org.junit.Assert.fail;
+
+/**
+*
+* Tracks one or more patterns to determine whether or not they have been
+* logged. It uses a streaming approach to determine whether or not a
message
+* has a occurred to prevent unnecessary memory consumption. Instances of
this
+* of this class are created using the {@link TestAppenderBuilder}.
+*
+* To use this class, register a one or more expected patterns by level as
part
+* of the test setup and retain an reference to the appender instance.
After the
+* expected logging events have occurred in the test case, call
+* {@link TestAppender#assertMessagesLogged()} which will fail the test if
any of the
+* expected patterns were not logged.
+*
+*/
+public final class TestAppender extends AppenderSkeleton {
+ private final static String APPENDER_NAME = "test_appender";
+ private final ImmutableMap<Level, Set<PatternResult>>
expectedPatternResults;
+ private TestAppender(final Map<Level, Set<PatternResult>>
expectedPatterns) {
+ super();
+ expectedPatternResults = ImmutableMap.copyOf(expectedPatterns);
+ }
+ protected void append(LoggingEvent loggingEvent) {
+ checkArgument(loggingEvent != null, "append requires a non-null
loggingEvent");
+ final Level level = loggingEvent.getLevel();
+ checkState(expectedPatternResults.containsKey(level), "level " +
level + " not supported by append");
+ for (final PatternResult patternResult :
expectedPatternResults.get(level)) {
+ if
(patternResult.getPattern().matcher(loggingEvent.getRenderedMessage()).matches())
{
+ patternResult.markFound();
+ }
+ }
+ }
+ public void close() {
+// Do nothing ...
+ }
+ public boolean requiresLayout() {
+ return false;
+ }
+ public void assertMessagesLogged() {
+ final List<String> unloggedPatterns = new ArrayList<>();
+ for (final Map.Entry<Level, Set<PatternResult>>
expectedPatternResult : expectedPatternResults.entrySet()) {
+ for (final PatternResult patternResults :
expectedPatternResult.getValue()) {
+ if (!patternResults.isFound()) {
+ unloggedPatterns.add(format("%1$s was not logged for
level %2$s",
+ patternResults.getPattern().toString(),
expectedPatternResult.getKey()));
+ }
+ }
+ }
+ if (!unloggedPatterns.isEmpty()) {
+ fail(Joiner.on(",").join(unloggedPatterns));
+ }
+ }
+ private static final class PatternResult {
+ private final Pattern pattern;
+ private boolean foundFlag = false;
+ private PatternResult(Pattern pattern) {
+ super();
+ this.pattern = pattern;
+ }
+ public Pattern getPattern() {
+ return pattern;
+ }
+ public void markFound() {
+ // This operation is thread-safe because the value will only ever
be switched from false to true. Therefore,
+ // multiple threads mutating the value for a pattern will not
corrupt the value ...
+ foundFlag = true;
+ }
+ public boolean isFound() {
+ return foundFlag;
+ }
+ @Override
+ public boolean equals(Object thatObject) {
+ if (this == thatObject) {
+ return true;
+ }
+ if (thatObject == null || getClass() != thatObject.getClass())
{
+ return false;
+ }
+ PatternResult thatPatternResult = (PatternResult) thatObject;
+ return foundFlag == thatPatternResult.foundFlag &&
+ Objects.equal(pattern, thatPatternResult.pattern);
+ }
+ @Override
+ public int hashCode() {
+ return Objects.hashCode(pattern, foundFlag);
+ }
+ @Override
+ public String toString() {
+ return format("Pattern Result [ pattern: %1$s, markFound: %2$s
]", pattern.toString(), foundFlag);
+ }
+ }
+
+ public static final class TestAppenderBuilder {
--- End diff --
Minor Nit: I should have named this class ``Builder`` since it is already
namespaced ``TestAppender``. I would recommend that change since ``new
TestAppender.Builder()`` is cleaner than
``newTestAppender.TestAppenderBuilder()``. (Cosmetic I know, but it hits my
naming OCD)
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