add log capture for verifying the logs in our code

.gitignore

@@ -6,7 +6,12 @@ build/
 !**/src/test/**/build/
 
 ### IntelliJ IDEA ###
-.idea/
+!.idea/
+.idea/*
+!.idea/google-java-format.xml
+!.idea/codeStyles/
+.idea/codeStyles/*
+!.idea/codeStyles/codeStyleConfig.xml
 *.iml
 *.ipr
 *.iws

build.gradle.kts

@@ -54,6 +54,7 @@ dependencies {
 
     testImplementation(platform("org.junit:junit-bom:$junitVersion"))
     testImplementation("org.junit.jupiter:junit-jupiter")
+    implementation("io.github.hakky54:logcaptor:2.12.7")
     testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }
 

config/pmd/ruleset.xml

@@ -13,6 +13,8 @@
     <rule ref="category/java/bestpractices.xml">
         <!-- slf4j's parameterized logging ({}) makes isDebugEnabled()-style guards unnecessary. -->
         <exclude name="GuardLogStatement"/>
+        <exclude name="UnitTestContainsTooManyAsserts"/>
+        <exclude name="UnitTestAssertionsShouldIncludeMessage"/>
     </rule>
     <rule ref="category/java/errorprone.xml"/>
     <rule ref="category/java/design.xml">

src/int-test/java/com/example/app/AppIntegrationTest.java

@@ -1,13 +1,30 @@
 package com.example.app;
 
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import nl.altindag.log.LogCaptor;
 import org.junit.jupiter.api.Test;
 
 class AppIntegrationTest {
 
+  private final LogCaptor logCaptor = LogCaptor.forClass(App.class);
+
   @Test
   void mainRunsWithoutThrowing() {
     assertDoesNotThrow(() -> App.main(new String[] {}));
   }
+
+  @Test
+  void mainLogsGreeting() {
+    App.main(new String[] {});
+    assertEquals("Hello, world!", logCaptor.getInfoLogs().getFirst());
+  }
+
+  @Test
+  void mainNoErrorMessages() {
+    App.main(new String[] {});
+    assertTrue(logCaptor.getErrorLogs().isEmpty());
+  }
 }