test: fix MavenLauncherTest to find paths using File separator (#2129)

src/test/java/spoon/MavenLauncherTest.java

@@ -3,6 +3,8 @@
 import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
 
+import java.io.File;
+import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.List;
 
@@ -63,7 +65,8 @@ public void mavenLauncherTestMultiModulesAndVariables() {
 		List<String> classpath = Arrays.asList(launcher.getEnvironment().getSourceClasspath());
 		// in order to work on CI, make sure the version is the same in Spoon pom.xml
 		// else, we cannot guarantee that the dependency is present in .m2 cache and the test might fail
-		String lookingFor = "junit/junit/4.12/junit-4.12.jar";
+
+		String lookingFor = Paths.get("junit","junit", "4.12", "junit-4.12.jar").toString();
 
 		boolean findIt = false;
 		for (String s : classpath) {