BAEL-3960

testing-modules/pom.xml

@@ -33,6 +33,7 @@
         <module>selenium-junit-testng</module>
         <module>spring-testing</module>
         <module>test-containers</module>
+        <module>testing-assertions</module>
         <module>testng</module>
         <module>junit-5-basics</module>
         <module>easymock</module>

testing-modules/testing-assertions/pom.xml

@@ -0,0 +1,28 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>testing-assertions</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.2.3</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.15.0</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

testing-modules/testing-assertions/src/main/java/com/baeldung/junit/log/BusinessWorker.java

@@ -0,0 +1,16 @@
+package com.baeldung.junit.log;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class BusinessWorker {
+    private static Logger LOGGER = LoggerFactory.getLogger(BusinessWorker.class);
+
+    public void generateLogs(String msg) {
+        LOGGER.trace(msg);
+        LOGGER.debug(msg);
+        LOGGER.info(msg);
+        LOGGER.warn(msg);
+        LOGGER.error(msg);
+    }
+}

testing-modules/testing-assertions/src/main/resources/logback.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <layout class="ch.qos.logback.classic.PatternLayout">
+            <Pattern>
+                %d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n
+            </Pattern>
+        </layout>
+    </appender>
+    <logger name="com.baeldung.junit.log" level="debug" additivity="false">
+        <appender-ref ref="CONSOLE"/>
+    </logger>
+    <root level="error">
+        <appender-ref ref="CONSOLE"/>
+    </root>
+</configuration>

testing-modules/testing-assertions/src/test/java/com/baeldung/junit/log/BusinessWorkerUnitTest.java

@@ -0,0 +1,48 @@
+package com.baeldung.junit.log;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.LoggerFactory;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.LoggerContext;
+
+public class BusinessWorkerUnitTest {
+    private static MemoryAppender memoryAppender;
+    private static final String LOGGER_NAME = "com.baeldung.junit.log";
+    private static final String MSG = "This is a test message!!!";
+
+    @Before
+    public void setup() {
+        Logger logger = (Logger) LoggerFactory.getLogger(LOGGER_NAME);
+        memoryAppender = new MemoryAppender();
+        memoryAppender.setContext((LoggerContext) LoggerFactory.getILoggerFactory());
+        logger.setLevel(Level.DEBUG);
+        logger.addAppender(memoryAppender);
+        memoryAppender.start();
+
+    }
+
+    @After
+    public void cleanUp() {
+        memoryAppender.reset();
+        memoryAppender.stop();
+    }
+
+    @Test
+    public void test() {
+        BusinessWorker worker = new BusinessWorker();
+        worker.generateLogs(MSG);
+
+        // I check that I only have 4 messages (all but trace)
+        assertThat(memoryAppender.countEventsForLogger(LOGGER_NAME)).isEqualTo(4);
+        // I look for a specific message at a specific level, and I only have 1
+        assertThat(memoryAppender.search(MSG, Level.INFO).size()).isEqualTo(1);
+        // I check that the entry that is not present is the trace level
+        assertThat(memoryAppender.contains(MSG, Level.TRACE)).isFalse();
+    }
+}

testing-modules/testing-assertions/src/test/java/com/baeldung/junit/log/MemoryAppender.java

@@ -0,0 +1,51 @@
+package com.baeldung.junit.log;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+
+/**
+ * In memory slf4j appender<br/>
+ * Convenient appender to be able to check slf4j invocations
+ */
+public class MemoryAppender extends ListAppender<ILoggingEvent> {
+    public void reset() {
+        this.list.clear();
+    }
+
+    public boolean contains(String string, Level level) {
+        return this.list.stream()
+          .anyMatch(event -> event.getMessage().toString().contains(string) 
+            && event.getLevel().equals(level));
+    }
+
+    public int countEventsForLogger(String loggerName) {
+        return (int) this.list.stream()
+          .filter(event -> event.getLoggerName().contains(loggerName)).count();
+    }
+
+    public List<ILoggingEvent> search(String string) {
+        return this.list.stream()
+          .filter(event -> event.getMessage().toString().contains(string))
+          .collect(Collectors.toList());
+    }
+
+    public List<ILoggingEvent> search(String string, Level level) {
+        return this.list.stream()
+          .filter(event -> event.getMessage().toString().contains(string) 
+            && event.getLevel().equals(level))
+          .collect(Collectors.toList());
+    }
+
+    public int getSize() {
+        return this.list.size();
+    }
+
+    public List<ILoggingEvent> getLoggedEvents() {
+        return Collections.unmodifiableList(this.list);
+    }
+}

testing-modules/testing-assertions/src/test/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <layout class="ch.qos.logback.classic.PatternLayout">
+            <Pattern>
+                %d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n
+            </Pattern>
+        </layout>
+    </appender>
+    <root level="error">
+        <appender-ref ref="CONSOLE"/>
+    </root>
+</configuration>