How to fix the code to test the case by JUnit and POI?

Question

Why I can't have succeed to test this case?

@Test
public void test_Should_be_0() throws Exception {

    HSSFCell cell = new HSSFWorkbook().createSheet().createRow(0).createCell(0);
    cell.setCellValue(0);

    assertTrue(cell == 0);

Thank you for your help.

how does it even compile, you try to compare a reference with `0`, which cannot work for sure. — Nicolas Filotto, Dec 05 '16 at 19:06
@NicolasFilotto: thank you for the quick reply, but when I wrote cell.setCellValue(0); Haven't I put the value in the cell? — Lost_in_the_code, Dec 05 '16 at 19:10
yes but it is not what you actually test, check my answer for more details — Nicolas Filotto, Dec 05 '16 at 19:11
Apache POI ships with a large number of unit tests, why not [look at some of those and learn from them](https://svn.apache.org/repos/asf/poi/trunk/src/testcases/org/apache/poi/ss)? — Gagravarr, Dec 06 '16 at 08:19

score 1 · Answer 1 · answered Dec 05 '16 at 19:09

1

Your test assertTrue(cell == 0) is not correct, indeed you try to compare an object's reference with 0 which cannot work as they are incompatible types, if you want to check whether the value of the cell is 0, you should rather do something like that:

assertEquals(0.0, cell.getNumericCellValue(), 0.0);

answered Dec 05 '16 at 19:09

Nicolas Filotto

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do you know any book to understand how to test the POI cells or project? – Lost_in_the_code Dec 05 '16 at 19:18
There is something wrong, if I pone: `assertEquals(1, cell.getNumericCellValue(), 3);` the test works correctly again, but this is false! – Lost_in_the_code Dec 05 '16 at 21:39
you set the value to 0, how could it be equal to 1? – Nicolas Filotto Dec 06 '16 at 06:21
maybe I have wrong something in the original code. Your method doesn't work on my eclipse, but works that below posted from me. I don't know why. – Lost_in_the_code Dec 06 '16 at 16:28
@Lost_in_the_codewhat do you mean by "Your method doesn't work"? What does it do? Do you get a little red X to the left of the `assertEquals`? Are your imports correct? – jmarkmurphy Dec 07 '16 at 14:01

Lost_in_the_code · Answer 2 · 2016-12-05T22:25:20.553

0

I think this one way to test the code:

1)

@Test
    public void test_Should_be_0() throws Exception {

        HSSFCell cell = new HSSFWorkbook().createSheet().createRow(0).createCell(0);
        cell.setCellValue(0);
        Assert.assertTrue(cell.getNumericCellValue() == 0);

or 2)

@Test
    public void test_Should_be_0() throws Exception {

        HSSFCell cell = new HSSFWorkbook().createSheet().createRow(0).createCell(0);
        cell.setCellValue(0);
        HSSFCell cell2 = new HSSFWorkbook().createSheet().createRow(0).createCell(0);
        cell2.setCellValue(0);
        Assert.assertTrue(cell.getNumericCellValue() == cell2.getNumericCellValue());

Because if the numbers are different the test doesn't work.

edited Dec 05 '16 at 22:25

answered Dec 05 '16 at 21:57

Lost_in_the_code

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The second example is a bad idea. If you are trying to test `setCellValue()` or `getNumericCellValue()` and one is bad, it will always fail the same way given the same input. So if `cell.setCellValue(0)` puts a `9999` in the cell, `assertTrue(cell.getNumericCellValue() == 0)` should fail because it should return a `9999`. But if you set the value of two cells witn `setCellValue(0)` and then use `getNumericCellValue()` to compare the results, they should be equal and your assert in test 2 will always pass, even if the function are bad. – jmarkmurphy Dec 07 '16 at 13:56

How to fix the code to test the case by JUnit and POI?

2 Answers2