### Question:
AlternateMixParametersBuilder extends AbstractPdfOutputParametersBuilder<AlternateMixMultipleInputParameters> implements SingleOutputTaskParametersBuilder<AlternateMixMultipleInputParameters> { @Override public AlternateMixMultipleInputParameters build() { AlternateMixMultipleInputParameters params = new AlternateMixMultipleInputParameters(); params.setCompress(isCompress()); params.setExistingOutputPolicy(existingOutput()); params.setVersion(getVersion()); params.setOutput(output); inputs.forEach(params::addInput); return params; }  @Override void output(FileTaskOutput output); @Override AlternateMixMultipleInputParameters build();  }### Answer:
@Test public void build() throws IOException { AlternateMixParametersBuilder victim = new AlternateMixParametersBuilder(); victim.compress(true); PdfMixInput first = new PdfMixInput(PdfFileSource.newInstanceNoPassword(folder.newFile("first.pdf")), true, 2); victim.addInput(first); FileTaskOutput output = mock(FileTaskOutput.class); victim.output(output); victim.existingOutput(ExistingOutputPolicy.OVERWRITE); PdfMixInput second = new PdfMixInput(PdfFileSource.newInstanceNoPassword(folder.newFile("second.pdf")), false, 4); victim.addInput(second); PdfMixInput third = new PdfMixInput(PdfFileSource.newInstanceNoPassword(folder.newFile("third.pdf"))); victim.addInput(third); victim.version(PdfVersion.VERSION_1_7); assertTrue(victim.hasInput()); AlternateMixMultipleInputParameters params = victim.build(); assertTrue(params.isCompress()); assertEquals(ExistingOutputPolicy.OVERWRITE, params.getExistingOutputPolicy()); assertEquals(PdfVersion.VERSION_1_7, params.getVersion()); assertEquals(3, params.getInputList().size()); assertEquals(first, params.getInputList().get(0)); assertEquals(second, params.getInputList().get(1)); assertEquals(third, params.getInputList().get(2)); assertTrue(params.getInputList().get(0).isReverse()); assertFalse(params.getInputList().get(1).isReverse()); assertFalse(params.getInputList().get(2).isReverse()); assertEquals(2, params.getInputList().get(0).getStep()); assertEquals(4, params.getInputList().get(1).getStep()); assertEquals(1, params.getInputList().get(2).getStep()); assertEquals(output, params.getOutput()); }