# Detecting test smells with PMD

In folder [`pmd-documentation`](../pmd-documentation) you will find the documentation of a selection of PMD rules designed to catch test smells.
Identify which of the test smells discussed in classes are implemented by these rules.

Use one of the rules to detect a test smell in one of the following projects:

- [Apache Commons Collections](https://github.com/apache/commons-collections)
- [Apache Commons CLI](https://github.com/apache/commons-cli)
- [Apache Commons Math](https://github.com/apache/commons-math)
- [Apache Commons Lang](https://github.com/apache/commons-lang)

Discuss the test smell you found with the help of PMD and propose here an improvement.
Include the improved test code in this file.

## Answer
On lance la commande 
`pmd check -d ./test_folder/commons-math/ -R category/java/errorprone.xml/DetachedTestCase -r results_q2_tp3.txt -f text`

---
`
./test_folder/commons-math/commons-math-legacy-core/src/test/java/org/apache/commons/math4/legacy/core/MathArraysTest.java:730:	DetachedTestCase:	Probable detached JUnit test case.
./test_folder/commons-math/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/SingularValueDecompositionTest.java:169:	DetachedTestCase:	Probable detached JUnit test case.
./test_folder/commons-math/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/linear/SingularValueDecompositionTest.java:202:	DetachedTestCase:	Probable detached JUnit test case.
./test_folder/commons-math/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/regression/MillerUpdatingRegressionTest.java:559:	DetachedTestCase:	Probable detached JUnit test case.
`
---
On a pris la première erreur : 
```
    public void testConcatenateEmptyArguments() {
        final double[] x = new double[] {0, 1, 2};
        final double[] y = new double[] {3};
        final double[] z = new double[] {};
        final double[] u = new double[] {0, 1, 2, 3};
        Assert.assertArrayEquals(u,  MathArrays.concatenate(x, z, y), 0);
        Assert.assertArrayEquals(u,  MathArrays.concatenate(x, y, z), 0);
        Assert.assertArrayEquals(u,  MathArrays.concatenate(z, x, y), 0);
        Assert.assertEquals(0,  MathArrays.concatenate(z, z, z).length);
    }
```

On peut voir que quand il n'y a pas l'annotation `@Test` au début de la class test
JUnit ne l'exécute donc pas.

Voici la correction: 
```
    @Test
    public void testConcatenateEmptyArguments() {
        final double[] x = new double[] {0, 1, 2};
        final double[] y = new double[] {3};
        final double[] z = new double[] {};
        final double[] u = new double[] {0, 1, 2, 3};
        Assert.assertArrayEquals(u,  MathArrays.concatenate(x, z, y), 0);
        Assert.assertArrayEquals(u,  MathArrays.concatenate(x, y, z), 0);
        Assert.assertArrayEquals(u,  MathArrays.concatenate(z, x, y), 0);
        Assert.assertEquals(0,  MathArrays.concatenate(z, z, z).length);
    }
```