Spy an already initialized Java object Mockito - java

I am using the Mocktio library to write some test cases, since I have an elaborate inhertance structure, I have a few objects which are instantiated in the parent class, and I would like to mock one of its function call. Does Mockito library provide any way to spy on a already initialized object?
Also, the object is not directly instantiable.
Similar to the following -
public class A {
protected static MyObject a;
public static void someMethod() {
a = myObjectBuilder.createObj();
}
}
And another class B looks something similar to
class B extends A {
#BeforeClass
public static void setUpBeforeClass() {
someMethod();
}
#Test
public void mockTest() {
// now mock behavior of some method of MyObject a
// Missing line to spy object a.
Mockito.doReturn(false).when(a).xyz();
/* Now call some method that triggers a.xyz()
again, it is not a direct call,
there are multiple layer of abstraction
*/
}
}
Edit: I have tried the following and it does not work
MyObject mock_object = Mockito.spy(a);
Mockito.doReturn(false).when(mock_object).xyz();


Basically, don't do initialisation in BeforeClass, it runs only once but
you need to have new spy in each test, or you must "reinitialise" spy object
before each test.
Please examine this code:
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.mockito.Mockito;
import static org.assertj.core.api.Assertions.assertThat;
class MyObject{
public String cos;
public MyObject(String cos) {
this.cos = cos;
}
public boolean xyz() {
return true;
}
}
class A {
protected static MyObject a;
public void someMethod() {
a = new MyObject("cccc");
}
}
public class B extends A {
#Before
public void setUpBeforeTest() {
someMethod();
}
#Test
public void mockTest() {
MyObject mock_object = Mockito.spy(a);
Mockito.doReturn(false).when(mock_object).xyz();
assertThat(mock_object.xyz()).isFalse();
}
#Test
public void mockTest2() {
MyObject mock_object = Mockito.spy(a);
Mockito.doReturn(true).when(mock_object).xyz();
assertThat(mock_object.xyz()).isTrue();
}
}
If you want it your way, please change:
public void someMethod() {
a = myObjectBuilder.createObj();
}
into:
public static void someMethod() {
a = myObjectBuilder.createObj();
}
You can't call non static method from static initialiser #BeforeClass:
class A {
protected static MyObject a;
public static void someMethod() {
a = new MyObject("cccc");
}
}
public class B extends A {
#BeforeClass
public static void setUpBeforeClass() {
someMethod();
}
#Test
public void mockTest() {
MyObject mock_object = Mockito.spy(a);
Mockito.doReturn(false).when(mock_object).xyz();
assertThat(mock_object.xyz()).isFalse();
}
#Test
public void mockTest2() {
MyObject mock_object = Mockito.spy(a);
// Here we replace original object with our spy
A.a = mock_object;
Mockito.doReturn(false).when(mock_object).xyz();
assertThat(a.xyz()).isFalse();
}
}
Another example (in this case we replace object a with mock (spy is not needed):
class MyObject{
public String cos;
public MyObject(String cos) {
this.cos = cos;
}
public boolean xyz() {
return true;
}
}
class A {
protected MyObject a;
public A() {
a = new MyObject("ggggg");
}
public String doSomethingWithA(){
if(a.xyz()){
return a.cos;
}
else{
return "aaaa";
}
}
}
#RunWith(MockitoJUnitRunner.class)
public class B {
#Mock
MyObject mock_object;
#InjectMocks
A systemUnderTest = new A();
#Test
public void mockTest1() {
Mockito.doReturn(false).when(mock_object).xyz();
assertThat(systemUnderTest.doSomethingWithA()).isEqualTo("aaaa");
}
#Test
public void mockTest2() {
Mockito.doReturn(true).when(mock_object).xyz();
assertThat(systemUnderTest.doSomethingWithA()).isNull();
}
}

Related

How to verify a method was called inside another method with Mockito

I'm fairly new to Mockito, and I've been looking for a way to verify that if I call the filter() method with the right string, that the foo method will get called once.
public class A
{
private final Config _config;
public A(Config config) { _config = config; }
public void filter(String str)
{
if(str.startsWith("a"))
{
if(str.contains("z"))
{
foo(config.getName());
}
}
}
private void foo(String bar)
{
(...)
}
}
Here is my current code:
#Test
public void testOne()
{
Config config = new Config(configFile);
A a = Mockito.spy(new A(config));
a.filter("abcz");
verify(a, times(1)).foo(someString);
}

Try to be more generic while such a test. If you don't need to specify what exactly argument should by passed then just use any():
import static org.mockito.ArgumentMatchers.any;
verify(a).foo(any(String.class));

Use an object in other methods of a test class

I have a test class in Android test package. There is a class that I've create an object in it. But other method of this test class can not use this object and can not recognize the result of that method. Why and what should I do? I used static too but can't...
#RunWith(AndroidJUnit4.class)
public class PatientDaoTest {
private static int newRowId;
public static PatientRecordEntity newPatient1;
public void generationRecord(){
newRowId = 0;
PatientRecordEntity newPatient1 = new PatientRecordEntity();
newPatient1.setPatient_db_ID("23456");
newPatient1.setPatient_race("Chines");
newRowId = (int) patientDao.addNewPatient(newPatient1);
newPatient1.setPid(newRowId);
}
#Test
public void addNewPatient() throws Exception {
boolean pin = false;
if (0 != newRowId) {
pin = true;
}
assertTrue("addNewPatient is not true", pin);
}

use the annotation #Before.
like:
public class HTest {
public static Integer i;
#Before
public void before(){
i = 10;
}
#Test
public void print() {
System.out.println(i);
}
}
This before method will be executed before print and i will be Initialized.

How to test given code using mockito

I want to test that fan.setState method is called or not
class OffState implements State {
#Override
public void changeState(Fan fan) {
fan.setState(new OnState());
}
}

Like this:
#RunWith(MockitoJUnitRunner.class)
public class OffStateTest {
#Mock
private Fan fan;
#Test
public void testChangeState() {
//Arrange
OffState offState = new OffState();
//Act
offState.changeState(fan);
//Assert
Mockito.verify(fan).setState(Mockito.any(OnState.class));
}
}

Unable to mock while implementing builder pattern

I'm having hard time to test a class(TestClass) which uses builder pattern(BuilderClass) in logic . I'm unable to mock builder class(BuilderClass). The following is simplified version of my logic.
public class TestClass {
public int methodA() {
ExternalDependency e = BuilerClass.builder().withName("xyz").withNumber(10).build();
return e.callExternalFunction();
}
}
And here is my builder class
public class BuilderClass {
public static BuilderClass builder() { return new BuilderClass(); }
int number;
String name;
public BuilderClass withName(String name) {
this.name = name;
return this;
}
public BuilderClass withNumber(int number) {
this.number = number;
return this;
}
public ExternalDependency build() {
return new ExternalDependency(name,number);
}
}
For my test class, I'm using Mockito with Dataprovider.
#RunWith(DataProviderRunner.class)
class TestClassTest {
#Mock private ExternalDependency e;
#Mock private BuilderClass b;
#InjectMocks private TestClass t;
#Before public void setUp() { MockitoAnnotations.initMocks(this); }
#Test public void testMethodA() {
when(b.withName(any(String.class)).thenReturn(b); //This is not mocking
when(b.withNumber(10)).thenReturn(b); //This is not mocking
Assert.notNull(this.t.methodA()); //Control while execution is going to implementation of withName and withNumber, which should not happen right.
}
Help me if I miss anything. Thanks
}

Similar to what kryger said in a comment above, you probably need to do a refactor like this:
In your class under test, create a seam to replace e by a mock:
public class TestClass {
public int methodA() {
ExternalDependency e = buildExternalDependency("xyz", 10);
return e.callExternalFunction();
}
protected ExternalDependency buildExternalDependency(String name, int number) {
return BuilerClass.builder().withName(name).withNumber(number).build();
}
}
In the test code, override the test class to replace e with a mock and to validate the inputs to the builder:
#RunWith(DataProviderRunner.class)
class TestClassTest {
#Mock private ExternalDependency e;
private TestClass t;
#Before public void setUp() {
MockitoAnnotations.initMocks(this);
t = new TestClass() {
#Override
protected ExternalDependency buildExternalDependency(String name, int number) {
// validate inputs:
Assert.assertEquals(10, number);
Assert.assertEquals("xyz", name);
return e; // provide the mock
}
}
}
#Test public void testMethodA() {
// TODO: mock behavior of callExternalFunction() here
Assert.notNull(this.t.methodA());
}
}
You may want to go further with the refactor to move buildExternalDependency() into a another class which could be mocked and injected in the constructor of TestClass.

Running two same tests with different arguments

I have a test with 15-20 different test cases, I want to run the same test with twice with two different parameters which are supposed to be passed to the test's BeforeClass method, for instance:
public class TestOne {
private static ClassToTest classToTest;
#BeforeClass
public static void setUp() throws Exception {
classToTest = new ClassToTest("Argument1", "Argument2");
}
#Test
public void testOne() {
........roughly 15 - 20 tests here
}
public class TestTwo {
private static ClassToTest classToTest;
#BeforeClass
public static void setUp() throws Exception {
classToTest = new ClassToTest("Argument3", "Argument4");
}
#Test
public void testOne() {
........roughly 15 - 20 tests here, same as in TestOne
}
As you can see the only difference between these two tests is in the setup method, which passes different values to the constructor of the ClassToTest. I don't want to replicate the test methods in both classes, but would prefer either inheritance or some other intelligent way to achieve this in one class.

This seems like a perfect use case for JUnit4's #Parameters; see https://blogs.oracle.com/jacobc/entry/parameterized_unit_tests_with_junit or http://www.mkyong.com/unittest/junit-4-tutorial-6-parameterized-test/ . That said, you'll have to move the initialization from the setUp method to a constructor for the test class.

For what it's worth, here is how you would do it with TestNG:
public class TestFactory {
#Factory
public Object[] createTests() {
return new Object[] {
new ClassToTest("arg1", "arg2"),
new ClassToTest("arg3", "arg4")
};
}
}
public class ClassToTest {
public ClassToTest(String arg1, String arg2) {
this.arg1 = arg1;
this.arg2 = arg2;
}
#Test
public void testOne() {
// use arg1 and arg2
}
}

Thanks all for your quick replies. This is how I did it finally
public abstract class Base {
final HeavyObject heavy;
protected Base(HeavyObject heavy) {
this.param = param;
}
#Test
public void test() {
param.doSomething();
}
#Test
.............More tests here
}
public class FirstTest extends Base{
private static HeavyObject param;
#BeforeClass
public static void init() {
param = new HeavyObject("arg1", "arg2");
}
public FirstTest() {
super(param);
}
}
public class SecondTest extends Base{
private static HeavyObject param;
#BeforeClass
public static void init() {
param = new HeavyObject("arg3", "arg4");
}
public FirstTest() {
super(param);
}
}
Base is an abstract class which has all the tests and FirstTest and SecondTest create their own objects with different parameters and pass it to the abstract class to use it.

As per the documentation (http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html):
A subclass does not inherit the private members of its parent class.
However, if the superclass has public or protected methods for
accessing its private fields, these can also be used by the subclass.

How about this:
public class TestOne {
private static ClassToTest classToTest1, classToTest2;
#BeforeClass
public static void setUp() throws Exception {
classToTest1 = new ClassToTest("Argument1", "Argument2");
classToTest2 = new ClassToTest("Argument3", "Argument4");
}
#Test
public void testOne() {
testOneImpl(classToTest1);
testOneImpl(classToTest2);
}
public void testOneImpl(ClassToTest classToTest) {
// exact samew as whatever your current testOne() test method is
}
....
}
EDIT:
Or to keep method count down:
public class TestOne {
private static List<ClassToTest> classesToTest;
#BeforeClass
public static void setUp() throws Exception {
classesToTest = new ArrayList<>;
classesToTest.add( new ClassToTest("Argument1", "Argument2"));
classesToTest.add( new ClassToTest("Argument3", "Argument4"));
}
#Test
public void testOne() {
for (ClassToTest classToTest: classesToTest) {
... same test content as before
}
}

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