I am trying to implement Parameterized test in which I have a set of input and expected values which I want to test using assertEquals method of JUnit. I'm using JUnit version 5.x for this I am passing the input value to my custom method defined in other package (that I'm testing) and I am checking it with an expected value with assertEquals method.
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.Arrays;
import java.util.Collection;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.runners.Parameterized.Parameters;
class StringHelperTest {
private StringHelper helper = new StringHelper();
private String input;
private String expectedOutput;
public String getInput() {
return input;
}
public void setInput(String input) {
this.input = input;
}
public String getExpectedOutput() {
return expectedOutput;
}
public void setExpectedOutput(String expectedOutput) {
this.expectedOutput = expectedOutput;
}
#Parameters
public static Collection<String[]> testConditions() {
String[][] expectedOutputs = { { "AACD", "CD" }, { "ACD", "CD" }, { "CDEF", "CDEF" }, { "CDAA", "CDAA" } };
return Arrays.asList(expectedOutputs);
}
#ParameterizedTest
#Test
public void truncateAInFirst2Positions_A_atStart() {
assertEquals(expectedOutput, helper.truncateAInFirst2Positions(input));
}
}
In the method testConditions() the actual and expected values are given as a 2 dimensinonal String array expectedOutputs {{<actual_value>,<expected_value>},{...}}.
How do I pass expectedOutputs array to the truncateAInFirst2Positions_A_atStart() method to test all conditions mentioned in expectedOutputs array
With JUnit 5 you have ParameterizedTest and a Source for the input parameters, which are simple the parameters of the method.
So you want a Method with this signature:
#ParameterizedTest
//Source Annotation
void truncateAInFirst2Positions_A_atStart(String actual, String expected) {
And now you look up a for your use case matching source. When you want to proivde your test data with your method you could use #MethodSource("testConditions"). The String in the annotation points to the static method providing your test data. The test will be executed x times where x is the count of pairs in your collection. The elements in your String Array will be used as method arguments.
For simple types like Strings a CSV source can be simpler and easier to read:
#CsvSource({
"AACD, CD",
"ACD, CD"
})
You can check all possible sources and possiblites in the offcial documentation:
https://junit.org/junit5/docs/current/user-guide/#writing-tests-parameterized-tests
Just for reference as the question is already answered, but if you need something else than strings (e.g. your own objects) you can use org.junit.jupiter.params.provider.Arguments.arguments, e.g.:
#ParameterizedTest
#MethodSource("provideMyObject")
void myTestMethod(ActualObject actual, ExpectedObject expected) {
// ...
}
static Stream<Arguments> provideMyObject() {
return Stream.of(
org.junit.jupiter.params.provider.Arguments.arguments(new ActualObject("foo"), new ExpectedObject("foo")),
org.junit.jupiter.params.provider.Arguments.arguments(new ActualObject("bar"), new ExpectedObject("bar))
);
}
see also: https://junit.org/junit5/docs/current/user-guide/#writing-tests-parameterized-tests-sources-MethodSource
I mostly write Selenium WebDriver tests in Java but I recently had to work on some Selenium tests written in Python using nose. I noticed a great nose tool that generates separate test cases while iterating over a set of values (e.g. for testing every item in a drop-down list and getting a result entry for each).
http://swordstyle.com/func_test_tutorial/part_one/extra_generative_tests.html
Is there something similar that I could use in junit?
Sure, take a look at the JUNIT Data Provider library
From the docs:
import static org.junit.Assert.*;
import org.junit.Test;
import org.junit.runner.RunWith;
import com.tngtech.java.junit.dataprovider.DataProvider;
import com.tngtech.java.junit.dataprovider.DataProviderRunner;
import com.tngtech.java.junit.dataprovider.UseDataProvider;
#RunWith(DataProviderRunner.class)
public class DataProviderTest {
#DataProvider
public static Object[][] dataProviderAdd() {
// #formatter:off
return new Object[][] {
{ 0, 0, 0 },
{ 1, 1, 2 },
/* ... */
};
// #formatter:on
}
#Test
#UseDataProvider("dataProviderAdd")
public void testAdd(int a, int b, int expected) {
// Given:
// When:
int result = a + b;
// Then:
assertEquals(expected, result);
}
}
Instead of constantly creating identical debug configuraitons for my test cases, I would like to be able to simply save a few arguments common across all my Junit tests, right click on a specific test, then run that single run config. IE I would like a single debug configuration that can take as an argument the current selected test case instead of requiring me to manually specify it every time in the JUnit run configuration. My only options in the dialog appear to be either to specify a single test class or run all the tests in the project. As a result, Eclipse is littered with dozens of run configurations for all my test cases.
Instead of specifying a specific test class, I'd like it to specify a variable like ${container_loc} or ${resource_loc} for the class to run as in this question. Is there a variable in Eclipse that specifies the current selected Java class that I could place in the test class field in the dialog?
A specific example where this is useful is when running the Lucene unit tests. There's lots of arguments you can specify to customize the tests, some of which like -ea are required. Everytime I want to test a specific test case in Lucene in Eclipse, I have to manually setup these variables in the Eclipse debug config dialog :-/.
Have you looked at Parameterized Tests in JUnit? Here is an example:
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
#RunWith(Parameterized.class)
public class ParamTest {
#Parameters(name = "{index}: fib({0})={1}")
public static Iterable<Object[]> data() {
return Arrays.asList(new Object[][] {
{ 0, 0 }, { 1, 1 }, { 2, 1 }, { 3, 2 }, { 4, 3 }, { 5, 5 }, { 6, 8 }
});
}
private int input;
private int expected;
public ParamTest(int input, int expected) {
this.input = input;
this.expected = expected;
}
#Test
public void test() {
Assert.assertEquals(expected, input);
}
}
If you just want to run one test at a time you can use private variables as in:
public class MultipleTest {
private int x;
private int y;
public void test1(){
Assert.assertEquals(x, y);
}
public void test2(){
Assert.assertTrue(x >y);
}
public void args1(){
x=10; y=1;
}
public void args2(){
x=1;y=1;
}
public void args3(){
x=1;y=10;
}
#Test
public void testArgs11(){
args1();
test1();
}
#Test
public void testArgs21(){
args2();
test1();
}
#Test
public void testArgs31(){
args3();
test1();
}
#Test
public void testArgs12(){
args1();
test2();
}
#Test
public void testArgs22(){
args2();
test2();
}
#Test
public void testArgs32(){
args3();
test2();
}
}
Is there a way to set my own custom test case names when using parameterized tests in JUnit4?
I'd like to change the default — [Test class].runTest[n] — to something meaningful.
This feature has made it into JUnit 4.11.
To use change the name of parameterized tests, you say:
#Parameters(name="namestring")
namestring is a string, which can have the following special placeholders:
{index} - the index of this set of arguments. The default namestring is {index}.
{0} - the first parameter value from this invocation of the test.
{1} - the second parameter value
and so on
The final name of the test will be the name of the test method, followed by the namestring in brackets, as shown below.
For example (adapted from the unit test for the Parameterized annotation):
#RunWith(Parameterized.class)
static public class FibonacciTest {
#Parameters( name = "{index}: fib({0})={1}" )
public static Iterable<Object[]> data() {
return Arrays.asList(new Object[][] { { 0, 0 }, { 1, 1 }, { 2, 1 },
{ 3, 2 }, { 4, 3 }, { 5, 5 }, { 6, 8 } });
}
private final int fInput;
private final int fExpected;
public FibonacciTest(int input, int expected) {
fInput= input;
fExpected= expected;
}
#Test
public void testFib() {
assertEquals(fExpected, fib(fInput));
}
private int fib(int x) {
// TODO: actually calculate Fibonacci numbers
return 0;
}
}
will give names like testFib[1: fib(1)=1] and testFib[4: fib(4)=3]. (The testFib part of the name is the method name of the #Test).
Looking at JUnit 4.5, its runner clearly doesn't support that, as that logic is buried inside a private class inside the Parameterized class. You could not use the JUnit Parameterized runner, and create your own instead which would understand the concept of names (which leads to the question of how you might set a name ...).
From a JUnit perspective, it would be nice if instead of (or in addition to) just passing an increment, they would pass the comma delimited arguments. TestNG does this. If the feature is important to you, you can comment on the yahoo mailing list referenced at www.junit.org.
I recently came across the same problem when using JUnit 4.3.1. I implemented a new class which extends Parameterized called LabelledParameterized. It has been tested using JUnit 4.3.1, 4.4 and 4.5. It reconstructs the Description instance using the String representation of the first argument of each parameter array from the #Parameters method. You can see the code for this at:
http://code.google.com/p/migen/source/browse/trunk/java/src/.../LabelledParameterized.java?r=3789
and an example of its use at:
http://code.google.com/p/migen/source/browse/trunk/java/src/.../ServerBuilderTest.java?r=3789
The test description formats nicely in Eclipse which is what I wanted since this makes failed tests a lot easier to find! I will probably further refine and document the classes over the next few days/weeks. Drop the '?' part of the URLs if you want the bleeding edge. :-)
To use it, all you have to do is copy that class (GPL v3), and change #RunWith(Parameterized.class) to #RunWith(LabelledParameterized.class) assuming the first element of your parameter list is a sensible label.
I don't know if any later releases of JUnit address this issue but even if they did, I can't update JUnit since all my co-developers would have to update too and we have higher priorities than re-tooling. Hence the work in the class to be compilable by multiple versions of JUnit.
Note: there is some reflection jiggery-pokery so that it runs across the different JUnit versions as listed above. The version specifically for JUnit 4.3.1 can be found here and, for JUnit 4.4 and 4.5, here.
With Parameterized as a model, I wrote my own custom test runner / suite -- only took about half an hour. It's slightly different from darrenp's LabelledParameterized in that it lets you specify a name explicitly rather than relying on the first parameter's toString().
It also doesn't use arrays because I hate arrays. :)
public class PolySuite extends Suite {
// //////////////////////////////
// Public helper interfaces
/**
* Annotation for a method which returns a {#link Configuration}
* to be injected into the test class constructor
*/
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public static #interface Config {
}
public static interface Configuration {
int size();
Object getTestValue(int index);
String getTestName(int index);
}
// //////////////////////////////
// Fields
private final List<Runner> runners;
// //////////////////////////////
// Constructor
/**
* Only called reflectively. Do not use programmatically.
* #param c the test class
* #throws Throwable if something bad happens
*/
public PolySuite(Class<?> c) throws Throwable {
super(c, Collections.<Runner>emptyList());
TestClass testClass = getTestClass();
Class<?> jTestClass = testClass.getJavaClass();
Configuration configuration = getConfiguration(testClass);
List<Runner> runners = new ArrayList<Runner>();
for (int i = 0, size = configuration.size(); i < size; i++) {
SingleRunner runner = new SingleRunner(jTestClass, configuration.getTestValue(i), configuration.getTestName(i));
runners.add(runner);
}
this.runners = runners;
}
// //////////////////////////////
// Overrides
#Override
protected List<Runner> getChildren() {
return runners;
}
// //////////////////////////////
// Private
private Configuration getConfiguration(TestClass testClass) throws Throwable {
return (Configuration) getConfigMethod(testClass).invokeExplosively(null);
}
private FrameworkMethod getConfigMethod(TestClass testClass) {
List<FrameworkMethod> methods = testClass.getAnnotatedMethods(Config.class);
if (methods.isEmpty()) {
throw new IllegalStateException("#" + Config.class.getSimpleName() + " method not found");
}
if (methods.size() > 1) {
throw new IllegalStateException("Too many #" + Config.class.getSimpleName() + " methods");
}
FrameworkMethod method = methods.get(0);
int modifiers = method.getMethod().getModifiers();
if (!(Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))) {
throw new IllegalStateException("#" + Config.class.getSimpleName() + " method \"" + method.getName() + "\" must be public static");
}
return method;
}
// //////////////////////////////
// Helper classes
private static class SingleRunner extends BlockJUnit4ClassRunner {
private final Object testVal;
private final String testName;
SingleRunner(Class<?> testClass, Object testVal, String testName) throws InitializationError {
super(testClass);
this.testVal = testVal;
this.testName = testName;
}
#Override
protected Object createTest() throws Exception {
return getTestClass().getOnlyConstructor().newInstance(testVal);
}
#Override
protected String getName() {
return testName;
}
#Override
protected String testName(FrameworkMethod method) {
return testName + ": " + method.getName();
}
#Override
protected void validateConstructor(List<Throwable> errors) {
validateOnlyOneConstructor(errors);
}
#Override
protected Statement classBlock(RunNotifier notifier) {
return childrenInvoker(notifier);
}
}
}
And an example:
#RunWith(PolySuite.class)
public class PolySuiteExample {
// //////////////////////////////
// Fixture
#Config
public static Configuration getConfig() {
return new Configuration() {
#Override
public int size() {
return 10;
}
#Override
public Integer getTestValue(int index) {
return index * 2;
}
#Override
public String getTestName(int index) {
return "test" + index;
}
};
}
// //////////////////////////////
// Fields
private final int testVal;
// //////////////////////////////
// Constructor
public PolySuiteExample(int testVal) {
this.testVal = testVal;
}
// //////////////////////////////
// Test
#Ignore
#Test
public void odd() {
assertFalse(testVal % 2 == 0);
}
#Test
public void even() {
assertTrue(testVal % 2 == 0);
}
}
You may also want to try JUnitParams: https://github.com/Pragmatists/JUnitParams
from junit4.8.2, you can create your own MyParameterized class by simply copy Parameterized class. change the getName() and testName() methods in TestClassRunnerForParameters.
None of it was working for me, so I got the source for Parameterized and modified it create a a new test runner. I didn't have to change much but IT WORKS!!!
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import org.junit.Assert;
import org.junit.internal.runners.ClassRoadie;
import org.junit.internal.runners.CompositeRunner;
import org.junit.internal.runners.InitializationError;
import org.junit.internal.runners.JUnit4ClassRunner;
import org.junit.internal.runners.MethodValidator;
import org.junit.internal.runners.TestClass;
import org.junit.runner.notification.RunNotifier;
public class LabelledParameterized extends CompositeRunner {
static class TestClassRunnerForParameters extends JUnit4ClassRunner {
private final Object[] fParameters;
private final String fParameterFirstValue;
private final Constructor<?> fConstructor;
TestClassRunnerForParameters(TestClass testClass, Object[] parameters, int i) throws InitializationError {
super(testClass.getJavaClass()); // todo
fParameters = parameters;
if (parameters != null) {
fParameterFirstValue = Arrays.asList(parameters).toString();
} else {
fParameterFirstValue = String.valueOf(i);
}
fConstructor = getOnlyConstructor();
}
#Override
protected Object createTest() throws Exception {
return fConstructor.newInstance(fParameters);
}
#Override
protected String getName() {
return String.format("%s", fParameterFirstValue);
}
#Override
protected String testName(final Method method) {
return String.format("%s%s", method.getName(), fParameterFirstValue);
}
private Constructor<?> getOnlyConstructor() {
Constructor<?>[] constructors = getTestClass().getJavaClass().getConstructors();
Assert.assertEquals(1, constructors.length);
return constructors[0];
}
#Override
protected void validate() throws InitializationError {
// do nothing: validated before.
}
#Override
public void run(RunNotifier notifier) {
runMethods(notifier);
}
}
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public static #interface Parameters {
}
private final TestClass fTestClass;
public LabelledParameterized(Class<?> klass) throws Exception {
super(klass.getName());
fTestClass = new TestClass(klass);
MethodValidator methodValidator = new MethodValidator(fTestClass);
methodValidator.validateStaticMethods();
methodValidator.validateInstanceMethods();
methodValidator.assertValid();
int i = 0;
for (final Object each : getParametersList()) {
if (each instanceof Object[])
add(new TestClassRunnerForParameters(fTestClass, (Object[]) each, i++));
else
throw new Exception(String.format("%s.%s() must return a Collection of arrays.", fTestClass.getName(), getParametersMethod().getName()));
}
}
#Override
public void run(final RunNotifier notifier) {
new ClassRoadie(notifier, fTestClass, getDescription(), new Runnable() {
public void run() {
runChildren(notifier);
}
}).runProtected();
}
private Collection<?> getParametersList() throws IllegalAccessException, InvocationTargetException, Exception {
return (Collection<?>) getParametersMethod().invoke(null);
}
private Method getParametersMethod() throws Exception {
List<Method> methods = fTestClass.getAnnotatedMethods(Parameters.class);
for (Method each : methods) {
int modifiers = each.getModifiers();
if (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))
return each;
}
throw new Exception("No public static parameters method on class " + getName());
}
public static Collection<Object[]> eachOne(Object... params) {
List<Object[]> results = new ArrayList<Object[]>();
for (Object param : params)
results.add(new Object[] { param });
return results;
}
}
You can create a method like
#Test
public void name() {
Assert.assertEquals("", inboundFileName);
}
While I wouldn't use it all the time it would be useful to figure out exactly which test number 143 is.
I make extensive use of static import for Assert and friends, so it is easy for me to redefine assertion:
private <T> void assertThat(final T actual, final Matcher<T> expected) {
Assert.assertThat(editThisToDisplaySomethingForYourDatum, actual, expected);
}
For example, you could add a "name" field to your test class, initialized in the constructor, and display that on test failure. Just pass it in as the first elements of your parameters array for each test. This also helps label the data:
public ExampleTest(final String testLabel, final int one, final int two) {
this.testLabel = testLabel;
// ...
}
#Parameters
public static Collection<Object[]> data() {
return asList(new Object[][]{
{"first test", 3, 4},
{"second test", 5, 6}
});
}
A workaround would be to catch and nest all Throwables into a new Throwable with a custom message that contains all information about the parameters. The message would appear in the stack trace.
This works whenever a test fails for all assertions, errors and exceptions as they are all subclasses of Throwable.
My code looks like this:
#RunWith(Parameterized.class)
public class ParameterizedTest {
int parameter;
public ParameterizedTest(int parameter) {
super();
this.parameter = parameter;
}
#Parameters
public static Collection<Object[]> data() {
return Arrays.asList(new Object[][] { {1}, {2} });
}
#Test
public void test() throws Throwable {
try {
assertTrue(parameter%2==0);
}
catch(Throwable thrown) {
throw new Throwable("parameter="+parameter, thrown);
}
}
}
The stack trace of the failed test is:
java.lang.Throwable: parameter=1
at sample.ParameterizedTest.test(ParameterizedTest.java:34)
Caused by: java.lang.AssertionError
at org.junit.Assert.fail(Assert.java:92)
at org.junit.Assert.assertTrue(Assert.java:43)
at org.junit.Assert.assertTrue(Assert.java:54)
at sample.ParameterizedTest.test(ParameterizedTest.java:31)
... 31 more
When you want the parameter values in test name then you can do something like -
#ParameterizedTest(name="{index} {arguments} then return false" )
#ValueSource(strings = {"false","FALSE"," ","123","abc"})
#DisplayName("When Feature JVM argument is ")
void test_Feature_JVM_Argument_Is_Empty_Or_Blank_Strings_Or_False(String params) {
System.setProperty("FeatureName", params);
assertFalse(Boolean.parseBoolean(System.getProperty("FeatureName")));
}
Test name will look like -
JUnit Test image
Check out JUnitParams as dsaff mentioned, works using ant to build parameterized test method descriptions in the html report.
This was after trying LabelledParameterized and finding that it although it works with eclipse it does not work with ant as far as the html report is concerned.
Cheers,
Since the parameter accessed (e.g. with "{0}" always returns the toString() representation, one workaround would be to make an anonymous implementation and override toString() in each case. For example:
public static Iterable<? extends Object> data() {
return Arrays.asList(
new MyObject(myParams...) {public String toString(){return "my custom test name";}},
new MyObject(myParams...) {public String toString(){return "my other custom test name";}},
//etc...
);
}
Parameterized test is calling toString() internally.
If you create an object wrapper overiding toString(), it will change the names of the test.
Here is an example, I answered in other post.
https://stackoverflow.com/a/67023556/1839360
For a more complex object you may do the following (example with JUnit 4):
#RunWith(Parameterized.class)
public class MainTest {
private static Object[] makeSample(String[] array, int expectedLength) {
return new Object[]{array, expectedLength, Arrays.toString(array)};
}
#Parameterized.Parameters(name = "for input {2} length should equal {1}")
public static Collection<Object[]> data() {
return Arrays.asList(
makeSample(new String[]{"a"}, 1),
makeSample(new String[]{"a", "b"}, 2)
);
}
private final int expectedLength;
private final String[] array;
public MainTest(String[] array, int expectedLength, String strArray) {
this.array = array;
this.expectedLength = expectedLength;
}
#Test
public void should_have_expected_length() {
assertEquals(expectedLength, array.length);
}
}
The trick here is to use one input parameter as a string describing either some part of input or the whole test case.
Before adding third parameter it looked like this
And after like this
import java.util.regex.Pattern;
public class TestUI {
private static Pattern p = Pattern.compile("^[A-Za-z0-9()+-]+$");
public static void main(String[] args) {
// Test case1
String[] str=test();
System.out.println(str[0]+str.length);
match("Alphanumeric(Text)");
}
private static String[] test() {
boolean res;
String[] array={"a","b","c","d","e"};
for(int i=0;i<array.length;i++){
System.out.println(match(array[i]));
res=match(array[i]);
if(res=true)
calltomethod(array);
}
return array;
}
private static boolean match(String s) {
return p.matcher(s).matches();
}
}
In the above code I need to pass the array as a argument to a JUnit method, the above code will be present in a JUnit class, can I have these kind of methods in a JUnit class and a test =method with argument?
You should take a look at parameterized unit tests (introduced in JUnit 4).
Daniel Mayer's blog has an example of this.
Another, more simple example is on mkyong's webpage
Yes you can with the Theories Runner in JUnit 4.4
#RunWith(Theories.class)
public class TheorieTest {
#DataPoints
public static String[] strings={"a","b","c","d","e"};
private static Pattern p = Pattern.compile("^[A-Za-z0-9()+-]+$");
#Theory
public void stringTest(String x) {
assertTrue("string " + x + " should match but does not", p.matcher(x).matches());
}
}
For more details:
Junit 4.4 Release Notes
Blog
yes, it can. recently i started zohhak project. it lets you write:
#TestWith({
"25 USD",
"38 GBP",
"null"
})
public void testMethod(Money money) {
...
}
You can't directly pass parameters to test methods with JUnit. TestNG allows it, though:
//This method will provide data to any test method that declares that its Data
// Provider is named "test1"
#DataProvider(name = "test1")
public Object[][] createData1() {
return new Object[][] {
{ "Cedric", new Integer(36) },
{ "Anne", new Integer(37)},
};
}
//This test method declares that its data should be supplied by the Data Provider
//named "test1"
#Test(dataProvider = "test1")
public void verifyData1(String n1, Integer n2) {
System.out.println(n1 + " " + n2);
}
will print:
Cedric 36
Anne 37