java TestNG 在@DataProvider 中使用@Parameters 调用方法

Question

I'm trying to get data using @DataProvider , which returns Object[][] , in which I'm pasting value by calling another method. This method, in its turn, using @Parameters to get value from XML.

The problem is that I'm getting NullPointerException , because in @DataProvider calling required method with @Parameters by passing value null , hoping that @Parameters will change this value to appropriate one from XML. At the same time, I cannot call method by not passing any arguments to it.

Code:

Class TestSuite

package blablabla.mainPackage;

import blablabla.framework.*;
import java.io.IOException;
import java.util.ArrayList;
import org.testng.annotations.Test;

public class TestSuite extends Config {
    FilesOperations fOps = new FilesOperations();
    List<String> fileNames = new ArrayList<String>();

    @Test(groups = {"positive"},
          dataProvider = "getRandomFileName",
          priority = 1)
    public void createFileRandom(String fileName) throws IOException {
        fOps.createFile(fileName, tempPath);
        fileNames.add(fileName);
    }   
}

Class Config

package blablabla.mainPackage;

import blablabla.framework.*;

import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.testng.annotations.AfterSuite;
import org.testng.annotations.BeforeSuite;
import org.testng.annotations.Parameters;

public class Config extends DataProviders{
    public static Path tempPath;

    DirectoriesOperations dirOps = new DirectoriesOperations();

    @BeforeSuite(alwaysRun = true)
    @Parameters({"path"})
    public void tearUp(String path) throws IOException {
        tempPath = dirOps.createTempDir(Paths.get(path));
    }

    @AfterSuite(alwaysRun = true, enabled = true)
    public void tearDown() throws IOException {
        dirOps.deleteTempDirOnExit(tempPath);
    }
}

Class DataProviders

package blablabla.framework;

import java.io.IOException;
import org.testng.annotations.DataProvider;

public class DataProviders {
    FilesOperations fOps = new FilesOperations();
    HelpFunctions hf = new HelpFunctions();
    ParametrizedFunctions pf = new ParametrizedFunctions();

    @DataProvider(name = "getRandomFileName")
    public Object[][] getRandomFileName() {
        return new Object[][]{new Object[]{pf.generateRandomFileNameWithExtension(null)}};
    }   
}

Class ParametrizedFunctions

package blablabla.framework;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.testng.annotations.Parameters;

public class ParametrizedFunctions {
    FilesOperations fOps = new FilesOperations();
    HelpFunctions hf = new HelpFunctions();

    @Parameters({"extensionsArray"})
    public String generateRandomFileNameWithExtension(String extensionsArray) {
        return fOps.getFileName(hf.stringToArray(extensionsArray), null);
    }
}

Here, @Parameters({"extensionsArray"}) does't provide a value from XML file. It just takes null , that was passed as an argument for calling method generateRandomFileNameWithExtension() . And, at the same time, I cannot call this method from @DataProvider without passing any argument to method called.

Hope for your suggestions.

Answer 1

I found the solution. The best way to pass parameter from XML into @DataProvider is passing ITestContext context as the argument to the @DataProvider method, and then, get required parameter using:

context.getCurrentXmlTest().getParameter("parameterName");

Full code of @DataProvider :

@DataProvider(name = "getRandomFileName")
    public Object[][] getRandomFileName(ITestContext context) {
        String extensionsArray = context.getCurrentXmlTest().getParameter("extensionsArray");
        return new Object[][]{new Object[]{pf.generateRandomFileNameWithExtension(extensionsArray)}};
    }

Thanks all for your suggestions.