Add test rule and property for better handling JNA if not available o…

…r in need of custom extension.

byte-buddy-agent/pom.xml

@@ -18,6 +18,7 @@
  <packages.list>net.bytebuddy.agent,net.bytebuddy.agent.utility.nullability</packages.list>
  <native.compiler.32>i686-w64-mingw32-gcc</native.compiler.32>
  <native.compiler.64>x86_64-w64-mingw32-gcc</native.compiler.64>
+ <net.bytebuddy.test.jnapath/>
  </properties>
 
  <name>Byte Buddy agent</name>
@@ -89,6 +90,15 @@
  </resource>
  </resources>
  <plugins>
+ <!-- Allow for specifying a custom library path for JNA. -->
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-surefire-plugin</artifactId>
+ <version>${version.plugin.surefire}</version>
+ <configuration combine.children="append">
+ <argLine>-Djna.library.path=${net.bytebuddy.test.jnapath}</argLine>
+ </configuration>
+ </plugin>
  <!-- Create manifest file which is required for creating an OSGi bundle. -->
  <plugin>
  <groupId>org.apache.maven.plugins</groupId>

byte-buddy-agent/src/test/java/net/bytebuddy/agent/VirtualMachineAttachmentTest.java

@@ -1,9 +1,12 @@
 package net.bytebuddy.agent;
 
 import net.bytebuddy.dynamic.ClassFileLocator;
+import net.bytebuddy.test.utility.JnaRule;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TestRule;
 
 import java.io.File;
 import java.io.FileOutputStream;
@@ -20,6 +23,9 @@ public class VirtualMachineAttachmentTest {
 
  private static final String FOO = "foo";
 
+ @Rule
+ public TestRule jnaRule = new JnaRule();
+
  private File agent;
 
  @Before

byte-buddy-agent/src/test/java/net/bytebuddy/test/utility/JnaRule.java

@@ -0,0 +1,46 @@
+package net.bytebuddy.test.utility;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import java.util.logging.Logger;
+
+public class JnaRule implements TestRule {
+
+ private final boolean available;
+
+ @SuppressWarnings("deprecation")
+ public JnaRule() {
+ boolean available;
+ try {
+ Native.loadLibrary((Platform.isWindows() ? "msvcrt" : "c"), CLibrary.class);
+ available = true;
+ } catch (Throwable ignored) {
+ available = false;
+ }
+ this.available = available;
+ }
+
+ public Statement apply(Statement base, Description description) {
+ return available
+ ? base
+ : new NoOpStatement();
+ }
+
+ private static class NoOpStatement extends Statement {
+
+ public void evaluate() {
+ Logger.getLogger("net.bytebuddy").info("Omitting test case: JNA not available");
+ }
+ }
+
+ public interface CLibrary extends Library {
+
+ @SuppressWarnings("unused")
+ void printf(String format, Object... args);
+ }
+}