@Test public void materializedColShouldBeWritten() throws Exception { File textFile = tmpDir.copyResourceFile("shakes.txt"); Pipeline pipeline = new MRPipeline(MRPipelineIT.class, tmpDir.getDefaultConfiguration()); PCollection<String> genericCollection = pipeline.readTextFile(textFile.getAbsolutePath()); pipeline.run(); PCollection<String> filter = genericCollection.filter("Filtering data", FilterFns.<String>ACCEPT_ALL()); filter.materialize(); pipeline.run(); File file = tmpDir.getFile("output.txt"); Target outFile = To.textFile(file.getAbsolutePath()); PCollection<String> write = filter.write(outFile); write.materialize(); pipeline.run(); }