infra: convert assertions to AssertJ

Tests are way more readable and specific with AssertJ assertions.

* add assertj and dependencies to target
* add assertj as compile time dependency, so it doesn't become part of
the released plugin
* use IllegalImport to avoid plain JUnit assertions

Author: Bananeweizen

config/checkstyle_checks.xml

@@ -389,7 +389,12 @@
         <!-- Imports -->
         <module name="AvoidStarImport"/>
         <module name="AvoidStaticImport"/>
-        <module name="IllegalImport"/>
+        <module name="IllegalImport">
+            <property name="illegalClasses"
+                      value="org.junit.jupiter.api.Assertions"/>
+            <message key="import.illegal"
+                     value="Use org.assertj.core.api.Assertions instead."/>
+        </module>
         <module name="ImportControl">
             <property name="id" value="ImportControlMain"/>
             <property name="file" value="${checkstyle.importcontrol.file}"/>

net.sf.eclipsecs.checkstyle/build.properties

@@ -6,3 +6,5 @@ bin.includes = META-INF/,\
 jars.compile.order = .
 source.. = metadata/
 javacDefaultEncoding.. = UTF-8
+additional.bundles = assertj-core,\
+                     net.bytebuddy.byte-buddy

net.sf.eclipsecs.checkstyle/test/net/sf/eclipsecs/checkstyle/ChecksTest.java

@@ -21,8 +21,7 @@
 package net.sf.eclipsecs.checkstyle;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -56,13 +55,13 @@ public void testMetadataFiles() throws Exception {
 
     final Set<String> packages = CheckUtil.getPackages(modules);
 
-    assertTrue(modules.size() > 0, "no modules");
+    assertThat(modules).as("modules").isNotEmpty();
 
     for (String p : packages) {
-      assertTrue(new File(getEclipseCsPath(p, "")).exists(), "folder " + p + " must exist in eclipsecs");
+      assertThat(new File(getEclipseCsPath(p, ""))).exists();
 
       final Set<Class<?>> packgeModules = CheckUtil.getModulesInPackage(modules, p);
-      assertTrue(packgeModules.size() > 0, "package must have modules");
+      assertThat(packgeModules).as("package modules").isNotEmpty();
 
       validateEclipseCsMetaXmlFile(new File(getEclipseCsPath(p, "/checkstyle-metadata.xml")), p);
 
@@ -72,36 +71,48 @@ public void testMetadataFiles() throws Exception {
   }
 
   private static void validateEclipseCsMetaXmlFile(File file, String packge) throws Exception {
-    assertTrue(file.exists(), "'checkstyle-metadata.xml' must exist in eclipsecs inside " + packge);
+    assertThat(file)
+            .withFailMessage(
+                    () -> "'checkstyle-metadata.xml' must exist in eclipsecs inside " + packge)
+            .exists();
 
     final String input = new String(Files.readAllBytes(file.toPath()), UTF_8);
     final Document document = XmlUtil.getRawXml(file.getAbsolutePath(), input, input);
 
     final NodeList ruleGroups = document.getElementsByTagName("rule-group-metadata");
 
-    assertEquals(1, ruleGroups.getLength(), packge + " checkstyle-metadata.xml must contain only one rule group");
+    assertThat(ruleGroups.getLength())
+            .withFailMessage(
+                    () -> packge + " checkstyle-metadata.xml must contain only one rule group")
+            .isEqualTo(1);
 
     for (int position = 0; position < ruleGroups.getLength(); position++) {
       final Node ruleGroup = ruleGroups.item(position);
       final Set<Node> children = XmlUtil.getChildrenElements(ruleGroup);
 
-      assertEquals(0, children.size(), packge + " checkstyle-metadata.xml must contain no rules");
+      assertThat(children)
+              .withFailMessage(() -> packge + " checkstyle-metadata.xml must contain no rules")
+              .isEmpty();
     }
   }
 
   private static void validateEclipseCsMetaPropFile(File file, String packge) throws Exception {
-    assertTrue(file.exists(), "'checkstyle-metadata.properties' must exist in eclipsecs inside " + packge);
+    assertThat(file).withFailMessage(
+            () -> "'checkstyle-metadata.properties' must exist in eclipsecs inside " + packge)
+            .exists();
 
     final Properties prop = new Properties();
     prop.load(new FileInputStream(file));
 
     final Set<Object> properties = new HashSet<>(Collections.list(prop.keys()));
 
-    assertEquals(1, properties.size(),
-            packge + " checkstyle-metadata.properties must contain only the rule group name");
+    assertThat(properties).withFailMessage(
+            () -> packge + " checkstyle-metadata.properties must contain only the rule group name")
+            .hasSize(1);
 
-    assertTrue(properties.iterator().next().toString().endsWith(".group"),
-            packge + " checkstyle-metadata.properties must contain only the rule group name");
+    assertThat(properties.iterator().next().toString()).withFailMessage(
+            () -> packge + " checkstyle-metadata.properties must contain only the rule group name")
+            .endsWith(".group");
   }
 
   private static String getEclipseCsPath(String packageName, String fileName) throws IOException {

net.sf.eclipsecs.checkstyle/test/net/sf/eclipsecs/checkstyle/utils/XmlUtil.java

@@ -20,7 +20,7 @@
 
 package net.sf.eclipsecs.checkstyle.utils;
 
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.io.IOException;
 import java.io.StringReader;

net.sf.eclipsecs.target/net.sf.eclipsecs.target.target

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <?pde?>
 <!-- generated with https://github.com/eclipse-cbi/targetplatform-dsl -->
-<target name="Eclipse Checkstyle" sequenceNumber="1695316836">
+<target name="Eclipse Checkstyle" sequenceNumber="1695470918">
   <locations>
     <location includeMode="slicer" includeAllPlatforms="false" includeSource="true" includeConfigurePhase="true" type="InstallableUnit">
       <unit id="org.eclipse.jdt.feature.group" version="3.18.800.v20210611-1600"/>
@@ -26,26 +26,38 @@
       <unit id="org.junit.platform.suite.api" version="1.7.1.v20210222-1948"/>
       <repository location="https://download.eclipse.org/tools/orbit/downloads/drops/R20210602031627/repository"/>
     </location>
-    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="MavenDependencies">
+    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="SnakeYaml">
     <dependencies>
     	<dependency>
-    		<groupId>org.dom4j</groupId>
-    		<artifactId>dom4j</artifactId>
-    		<version>2.1.3</version>
+    		<groupId>org.yaml</groupId>
+    		<artifactId>snakeyaml</artifactId>
+    		<version>1.33</version>
     		<type>jar</type>
     	</dependency>
+    </dependencies>
+    </location>
+    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="Javassist">
+    <dependencies>
     	<dependency>
     		<groupId>org.javassist</groupId>
     		<artifactId>javassist</artifactId>
     		<version>3.29.2-GA</version>
     		<type>jar</type>
     	</dependency>
+    </dependencies>
+    </location>
+    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="DOM4J">
+    <dependencies>
     	<dependency>
-    		<groupId>org.yaml</groupId>
-    		<artifactId>snakeyaml</artifactId>
-    		<version>1.33</version>
+    		<groupId>org.dom4j</groupId>
+    		<artifactId>dom4j</artifactId>
+    		<version>2.1.3</version>
     		<type>jar</type>
     	</dependency>
+    </dependencies>
+    </location>
+    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="JFreeCharts">
+    <dependencies>
     	<dependency>
     		<groupId>org.jfree</groupId>
     		<artifactId>jcommon</artifactId>
@@ -70,6 +82,20 @@
     		<version>1.1.0</version>
     		<type>jar</type>
     	</dependency>
+    </dependencies>
+    </location>
+    <location includeDependencyDepth="direct" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="AssertJ">
+    <dependencies>
+    	<dependency>
+    		<groupId>org.assertj</groupId>
+    		<artifactId>assertj-core</artifactId>
+    		<version>3.24.2</version>
+    		<type>jar</type>
+    	</dependency>
+    </dependencies>
+    </location>
+    <location includeDependencyDepth="none" includeDependencyScopes="compile" includeSource="true" missingManifest="generate" type="Maven" label="ApacheCommons">
+    <dependencies>
     	<dependency>
     		<groupId>org.apache.commons</groupId>
     		<artifactId>commons-lang3</artifactId>

net.sf.eclipsecs.target/net.sf.eclipsecs.target.tpd

@@ -35,27 +35,36 @@ location "https://download.eclipse.org/tools/orbit/downloads/drops/R202106020316
 
 // If the following part has errors and no syntax highlighting, then please use Help>About>Installation>Installed Software>Target Platform DSL>Uninstall.
 // After restarting please install the current version from the URL in line 1.
-maven MavenDependencies
+maven ApacheCommons
 	scope=compile
 	dependencyDepth=none
 	missingManifest=generate
 	includeSources
 {
 	dependency {
-		groupId="org.dom4j"
-		artifactId="dom4j"
-		version="2.1.3"
-	}
-	dependency {
-		groupId="org.javassist"
-		artifactId="javassist"
-		version="3.29.2-GA"
+		groupId="org.apache.commons"
+		artifactId="commons-lang3"
+		version="3.12.0"
 	}
+}
+maven AssertJ
+	scope=compile
+	dependencyDepth=direct
+	missingManifest=generate
+	includeSources
+{
 	dependency {
-		groupId="org.yaml"
-		artifactId="snakeyaml"
-		version="1.33"
+		groupId="org.assertj"
+		artifactId="assertj-core"
+		version="3.24.2"
 	}
+}
+maven JFreeCharts
+	scope=compile
+	dependencyDepth=none
+	missingManifest=generate
+	includeSources
+{
 	dependency {
 		groupId="org.jfree"
 		artifactId="jcommon"
@@ -76,9 +85,40 @@ maven MavenDependencies
 		artifactId="swtgraphics2d"
 		version="1.1.0"
 	}
+}
+maven DOM4J
+	scope=compile
+	dependencyDepth=none
+	missingManifest=generate
+	includeSources
+{
 	dependency {
-		groupId="org.apache.commons"
-		artifactId="commons-lang3"
-		version="3.12.0"
+		groupId="org.dom4j"
+		artifactId="dom4j"
+		version="2.1.3"
+	}
+}
+maven Javassist
+	scope=compile
+	dependencyDepth=none
+	missingManifest=generate
+	includeSources
+{
+	dependency {
+		groupId="org.javassist"
+		artifactId="javassist"
+		version="3.29.2-GA"
+	}
+}
+maven SnakeYaml
+	scope=compile
+	dependencyDepth=none
+	missingManifest=generate
+	includeSources
+{
+	dependency {
+		groupId="org.yaml"
+		artifactId="snakeyaml"
+		version="1.33"
 	}
 }

net.sf.eclipsecs.ui/build.properties

@@ -8,5 +8,6 @@ bin.includes = icons/,\
 jars.compile.order = .
 source.. = src/
 additional.bundles = org.eclipse.jdt.core,\
-                     org.eclipse.core.runtime
+                     org.eclipse.core.runtime,\
+                     assertj-core
 javacDefaultEncoding.. = UTF-8

net.sf.eclipsecs.ui/test/net/sf/eclipsecs/ui/quickfixes/AbstractQuickfixTestCase.java

@@ -20,8 +20,7 @@
 
 package net.sf.eclipsecs.ui.quickfixes;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -50,13 +49,10 @@ public abstract class AbstractQuickfixTestCase {
 
   protected void testQuickfix(final String testDataXml, final AbstractASTResolution quickfix)
           throws Exception {
-    InputStream stream = getClass().getResourceAsStream(testDataXml);
-    assertNotNull(stream, "Cannot find resource " + testDataXml + " in package "
-            + getClass().getPackage().getName());
-    try {
+    try (InputStream stream = getClass().getResourceAsStream(testDataXml)) {
+      assertThat(stream).withFailMessage(() -> "Cannot find resource " + testDataXml + " in package "
+            + getClass().getPackage().getName()).isNotNull();
       testQuickfix(stream, quickfix);
-    } finally {
-      stream.close();
     }
   }
 
@@ -88,7 +84,8 @@ protected void testQuickfix(InputStream testdataStream, AbstractASTResolution qu
       TextEdit edit = compUnit.rewrite(doc, options);
       edit.apply(doc);
 
-      assertEquals(testdata[i].result, doc.get().lines().map(String::stripTrailing).collect(Collectors.joining("\n")));
+      String trailingSpaceRemoved = doc.get().lines().map(String::stripTrailing).collect(Collectors.joining("\n"));
+      assertThat(trailingSpaceRemoved).isEqualTo(testdata[i].result);
     }
 
   }