Ensure that .jar files include the correct sources

Now that we use a MiniMaven version that includes sources correctly, we
might just as well ensure that it keeps doing so, even in future versions.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

src/test/java/org/scijava/plugins/scripting/java/MakeJarTest.java

@@ -59,6 +59,10 @@ public void testSingle() throws Exception {
 		engine.makeJar(file, false, output, writer);
 		assertJarEntries(output, "META-INF/MANIFEST.MF",
 				"META-INF/maven/net.imagej/Dummy/pom.xml", "Dummy.class");
+		engine.makeJar(file, true, output, writer);
+		assertJarEntries(output, "META-INF/MANIFEST.MF",
+				"META-INF/maven/net.imagej/Dummy/pom.xml", "Dummy.class",
+				"pom.xml", "src/main/java/Dummy.java");
 	}
 
 	private void assertJarEntries(File output, String... paths) throws IOException {