Easy way to get a test file into JUnit

Question

Can somebody suggest an easy way to get a reference to a file as a String InputStream File etc type object in a junit test class   Obviously I could paste the file  xml in this case  in as a giant String or read it in as a file but is there a shortcut specific to Junit like this   public class MyTestClass    Resource path  something xml   File myTestFile    Test public void toSomeTest

User · Answer

You can try doing   String myResource   IOUtils toString this getClass   getResourceAsStream  yourfile xml    replace   n

User · Answer

If you need to actually get a File object  you could do the following   URL url   this getClass   getResource   test wsdl    File testWsdl   new File url getFile       Which has the benefit of working cross platform  as described in this blog post

User · Answer

If you want to load a test resource file as a string with just few lines of code and without any extra dependencies  this does the trick   public String loadResourceAsString String fileName  throws IOException       Scanner scanner   new Scanner getClass   getClassLoader   getResourceAsStream fileName        String contents   scanner useDelimiter    A   next        scanner close        return contents         A  matches the start of input and there s only ever one  So this parses the entire file contents and returns it as a string  Best of all  it doesn t require any 3rd party libraries  like IOUTils

User · Answer

I know you said you didn t want to read the file in by hand  but this is pretty easy  public class FooTest       private BufferedReader in   null        Before     public void setup           throws IOException               in   new BufferedReader              new InputStreamReader getClass   getResourceAsStream   data txt                  After     public void teardown           throws IOException               if  in    null                        in close                       in   null              Test     public void testFoo           throws IOException               String line   in readLine             assertThat line  notNullValue               All you have to do is ensure the file in question is in the classpath  If you re using Maven  just put the file in src test resources and Maven will include it in the classpath when running your tests  If you need to do this sort of thing a lot  you could put the code that opens the file in a superclass and have your tests inherit from that

User · Answer

You can try  Rule annotation  Here is the example from the docs   public static class UsesExternalResource       Server myServer   new Server          Rule public ExternalResource resource   new ExternalResource              Override         protected void before   throws Throwable               myServer connect                         Override         protected void after                 myServer disconnect                            Test public void testFoo             new Client   run myServer             You just need to create FileResource class extending ExternalResource   Full Example  import static org junit Assert     import org junit Rule  import org junit Test  import org junit rules ExternalResource   public class TestSomething        Rule     public ResourceFile res   new ResourceFile   res txt          Test     public void test   throws Exception               assertTrue res getContent   length    gt  0           assertTrue res getFile   exists                 import java io BufferedReader  import java io File  import java io FileOutputStream  import java io FileReader  import java io IOException  import java io InputStream  import java io InputStreamReader  import java nio charset Charset   import org junit rules ExternalResource   public class ResourceFile extends ExternalResource       String res      File file   null      InputStream stream       public ResourceFile String res                this res   res             public File getFile   throws IOException               if  file    null                        createFile                      return file             public InputStream getInputStream                 return stream             public InputStream createInputStream                 return getClass   getResourceAsStream res              public String getContent   throws IOException               return getContent  utf-8               public String getContent String charSet  throws IOException               InputStreamReader reader   new InputStreamReader createInputStream                Charset forName charSet            char   tmp   new char 4096           StringBuilder b   new StringBuilder            try                       while  true                                int len   reader read tmp                   if  len  lt  0                                        break                                    b append tmp  0  len                             reader close                      finally                       reader close                      return b toString                Override     protected void before   throws Throwable               super before            stream   getClass   getResourceAsStream res               Override     protected void after                 try                       stream close                      catch  IOException e                           ignore                   if  file    null                        file delete                      super after               private void createFile   throws IOException               file   new File     res           InputStream stream   getClass   getResourceAsStream res           try                       file createNewFile                FileOutputStream ostream   null              try                               ostream   new FileOutputStream file                   byte   buffer   new byte 4096                   while  true                                        int len   stream read buffer                       if  len  lt  0                                                break                                            ostream write buffer  0  len                                               finally                               if  ostream    null                                        ostream close                                                      finally                       stream close

[java] Easy way to get a test file into JUnit

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