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Mokito/Java - Static Methods Mock

For example I have the following classes below:
public class TesteEstatico {
public static String teste(){
return "FOO";
}
}
And I have a class that uses her method:
public class UsaTesteEstatico {
public String metodoParaTeste1 (){
return TesteEstatico.teste() + " BAR ";
}
public String metodoParaTeste2 (){
return "FOO "+TesteEstatico.teste() + " BAR ";
}
}
Test class:
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mockito;
import org.mockito.junit.jupiter.MockitoExtension;
#ExtendWith(MockitoExtension.class) public class UsaTesteEstaticoTest {
#InjectMocks
UsaTesteEstatico usaTesteEstatico;
#Test
void teste1(){
Mockito.mockStatic(TesteEstatico.class);
Mockito.when(TesteEstatico.teste())
.thenReturn("BANANA");
String res = usaTesteEstatico.metodoParaTeste1();
System.out.println(res);
}
#Test
void teste2(){
Mockito.mockStatic(TesteEstatico.class);
Mockito.when(TesteEstatico.teste())
.thenReturn("LARANJA");
String res = usaTesteEstatico.metodoParaTeste2();
System.out.println(res);
}
}
Error I get when trying to run the tests:
org.mockito.exceptions.base.MockitoException:
For TesteEstatico, static mocking is already registered in the current thread
To create a new mock, the existing static mock registration must be deregistered
Versions of the libs that are in the project:
junit-jupiter 5.5.2
mockito-junit-jupiter 3.2.14
mockito-inline 3.2.14
Any idea how to solve this, i've tried a few things but nothing successful.
NOTE: I cannot change or add any new libraries as it is a restricted project.

You should use try-with-resources block in each of the tests to close the mockStatic.
public class UsaTesteEstaticoTest {
UsaTesteEstatico usaTesteEstatico = new UsaTesteEstatico();
#Test
void teste1(){
try (var ms = Mockito.mockStatic(TesteEstatico.class)) {
Mockito.when(TesteEstatico.teste()).thenReturn("BANANA");
String res = usaTesteEstatico.metodoParaTeste1();
System.out.println(res);
}
}
#Test
void teste2(){
try (var ms = Mockito.mockStatic(TesteEstatico.class)) {
Mockito.when(TesteEstatico.teste()).thenReturn("LARANJA");
String res = usaTesteEstatico.metodoParaTeste2();
System.out.println(res);
}
}
}
Note on mockStatic in #BeforeAll
Using #BeforeAll is a trap and bad advice.
You should strive for independent tests that don't affect each other.
This is not the case for mockStatic called in #BeforeAll, as stubbing from test methods outlive the test methods.
For example
// BAD CODE DONT USE
public class UsaTesteEstaticoTest {
UsaTesteEstatico usaTesteEstatico = new UsaTesteEstatico();
static MockedStatic<TesteEstatico> ms;
#BeforeAll
public static void init() {
ms = Mockito.mockStatic(TesteEstatico.class);
}
#AfterAll
public static void close() {
ms.close();
}
#Test
void teste1() {
Mockito.when(TesteEstatico.teste()).thenReturn("BANANA");
String res = usaTesteEstatico.metodoParaTeste1();
System.out.println(res);
}
#Test
void teste2() {
String res = usaTesteEstatico.metodoParaTeste2();
System.out.println(res);
}
}
teste2 prints:
FOO BANANA BAR if run after teste1
FOO null BAR if run separately
This is precisely what you want to avoid.

you need to use static block to mock it.
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mockito;
import org.mockito.junit.jupiter.MockitoExtension;
#ExtendWith(MockitoExtension.class)
public class UsaTesteEstaticoTest {
#InjectMocks
UsaTesteEstatico usaTesteEstatico;
#BeforeAll
public static void init(){
Mockito.mockStatic(TesteEstatico.class);
}
#Test
void teste1(){
Mockito.when(TesteEstatico.teste())
.thenReturn("BANANA");
String res = usaTesteEstatico.metodoParaTeste1();
System.out.println(res);
}
#Test
void teste2(){
Mockito.when(TesteEstatico.teste())
.thenReturn("LARANJA");
String res = usaTesteEstatico.metodoParaTeste2();
System.out.println(res);
}
}

Calling a Async method inside a for loop

I have a model:
package com.example.asyncmethod;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
#JsonIgnoreProperties(ignoreUnknown=true)
public class User {
private String name;
private String blog;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getBlog() {
return blog;
}
public void setBlog(String blog) {
this.blog = blog;
}
#Override
public String toString() {
return "User [name=" + name + ", blog=" + blog + "]";
}
}
a service call like below
package com.example.asyncmethod;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import java.util.concurrent.CompletableFuture;
#Service
public class GitHubLookupService {
private static final Logger logger = LoggerFactory.getLogger(GitHubLookupService.class);
private final RestTemplate restTemplate;
public GitHubLookupService(RestTemplateBuilder restTemplateBuilder) {
this.restTemplate = restTemplateBuilder.build();
}
#Async
public CompletableFuture<User> findUser(Integer user) throws InterruptedException {
logger.info("Looking up " + user);
String url = String.format("https://api.github.com/users/%s", user);
User results = restTemplate.getForObject(url, User.class);
Thread.sleep(1000L);
return CompletableFuture.completedFuture(results);
}
}
Async runner class:
package com.example.asyncmethod;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;
import java.util.concurrent.CompletableFuture;
#Component
public class AppRunner implements CommandLineRunner {
private static final Logger logger = LoggerFactory.getLogger(AppRunner.class);
private final GitHubLookupService gitHubLookupService;
public AppRunner(GitHubLookupService gitHubLookupService) {
this.gitHubLookupService = gitHubLookupService;
}
#Override
public void run(String... args) throws Exception {
// Start the clock
long start = System.currentTimeMillis();
// in real use case before the for loop I will have a database call to get the number of records and based on the size I need to call that many number of times.
for(int i=0; i <= 10; i++){
CompletableFuture<User> page1 = gitHubLookupService.findUser(1);
}
// Wait until they are all done
CompletableFuture.allOf(page1).join();
// Print results, including elapsed time
logger.info("Elapsed time: " + (System.currentTimeMillis() - start));
logger.info("--> " + page1.get());
}
}
So in the above for loop, I might call the findUser as per the number of records returned by DB.
Also in the future I might need to add few more async calls like findOrders, findInventory, findAccess etc which will call another services over http.
Considering the async call may succeed for one record and fail for another record, how can I approach here to call the async in the best possible way?

If you want to realize complete advantage of Async calls, I will suggest to avoid using CompletableFuture.get() or CompletableFuture.join().
Using this calls blocks your main thread till the time all the tasks (as part of CompletableFuture.allOf() ) are completed.
Instead you can use various functions that are provided to run a Lamba function on completion of all the futures (Also allows to handle failure in any of the Future).
Please refer the Java Docs for more details and check which method is more convenient in your implementation:
https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html

how to resolve NullPointerException in Junit for NeticaJ?

//This is my Main Class here when i call methodTwo in this class i got numnodes=4 but when i tried to access methodTwo in testclass i got NullPointerException.
package Netica;
import norsys.netica.Environ;
import norsys.netica.Net;
import norsys.netica.NodeList;
import norsys.netica.Streamer;
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
import NeticaTestCases.HNetTest;
public class HNet {
private static long startTime = System.currentTimeMillis();
private static Net net;
private static NodeList nodes;
int numNodes;
public int methodOne() {
System.out.println("we are in first methodOne");
return 1;
}
public int methodTwo() {
numNodes = nodes.size();
System.out.println("we are in 2nd methodTwo");
return numNodes;
}
public static void main(String[] args) {
try {
// Read in the net file and get list of all nodes and also Total
// number of nodes:
net = new Net(neStreamer("DataFiles/KSA_4_Nodes_noisySum.dne"));
nodes = net.getNodes();
HNet temp = new HNet();
temp.methodOne();
System.out.println("numNodes========>"+temp.methodTwo());//get 4
} catch (Exception e) {
}
}
}
//this is my testclass
package NeticaTestCases;
import static org.junit.Assert.assertEquals;
import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.fail;
import Netica.HNet;
public class HNetTest {
HNet temp;
#Before
public void setUp() {
temp = new HNet ();
}
#Test
public void CheckNumNodes() {
temp.methodOne();
System.out.println("numNodes========>"+temp.methodTwo());
}
}
please help me out how to resolve NullPointerException in junit testcases.

Adding a statement initialising the nodes should get you rid of the exception -
#Before
public void setUp() {
temp = new HNet ();
temp.nodes = new NodeList();
}
Also, would suggest you to try and improve on few points -
Debug the difference between your main method and CheckNumNodes() test method.
Use of getters and setters

Is it possible to use partial mocking for private static methods in PowerMock?

From the examples on the PowerMock homepage, I see the following example for partially mocking a private method with Mockito:
#RunWith(PowerMockRunner.class)
// We prepare PartialMockClass for test because it's final or we need to mock private or static methods
#PrepareForTest(PartialMockClass.class)
public class YourTestCase {
#Test
public void privatePartialMockingWithPowerMock() {
PartialMockClass classUnderTest = PowerMockito.spy(new PartialMockClass());
// use PowerMockito to set up your expectation
PowerMockito.doReturn(value).when(classUnderTest, "methodToMock", "parameter1");
// execute your test
classUnderTest.execute();
// Use PowerMockito.verify() to verify result
PowerMockito.verifyPrivate(classUnderTest, times(2)).invoke("methodToMock", "parameter1");
}
However, this approach does not seem to work when the private method we wish to mock is static. I wish to create a partial mock of the below class, with the readFile method mocked:
package org.rich.powermockexample;
import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.List;
import static com.google.common.io.Files.readLines;
public class DataProvider {
public static List<String> getData() {
List<String> data = null;
try {
data = readFile();
} catch (IOException e) {
e.printStackTrace();
}
return data;
}
private static List<String> readFile() throws IOException {
File file = new File("/some/path/to/file");
List<String> lines = readLines(file, Charset.forName("utf-8"));
return lines;
}
}
Please could someone let me know how this can be achieved?

After doing a bit more research, it seems that PowerMockito.spy() and PowerMockito.doReturn() are what is required here:
package com.richashworth.powermockexample;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.util.ArrayList;
import java.util.List;
import static org.junit.Assert.assertEquals;
#RunWith(PowerMockRunner.class)
#PrepareForTest({DataProvider.class})
public class ResultsWriterTest {
private static List<String> mockData = new ArrayList<String>();
private ResultsWriter resultsWriter;
#BeforeClass
public static void setUpOnce() {
final String firstLine = "Line 1";
final String secondLine = "Line 2";
mockData.add(firstLine);
mockData.add(secondLine);
}
#Before
public void setUp() {
resultsWriter = new ResultsWriter();
}
#Test
public void testGetDataAsString() throws Exception {
PowerMockito.spy(DataProvider.class);
PowerMockito.doReturn(mockData).when(DataProvider.class, "readFile");
final String expectedData = "Line 1\nLine 2\n";
final String returnedString = resultsWriter.getDataAsString();
assertEquals(expectedData, returnedString);
}
}
For further details and the complete code listing, check out my blog post here: https://richashworth.com/post/turbocharge-your-mocking-framework-with-powermock/

Test class:
#RunWith(PowerMockRunner.class)
#PrepareForTest(DataProvider.class)
public class DataProviderTest {
#Test
public void testGetDataWithMockedRead() throws Exception {
mockStaticPartial(DataProvider.class, "readFile");
Method[] methods = MemberMatcher.methods(DataProvider.class, "readFile");
expectPrivate(DataProvider.class, methods[0]).andReturn(Arrays.asList("ohai", "kthxbye"));
replay(DataProvider.class);
List<String> theData = DataProvider.getData();
assertEquals("ohai", theData.get(0));
assertEquals("kthxbye", theData.get(1));
}
}
Class being tested (basically yours):
public class DataProvider {
public static List<String> getData() {
try {
return readFile();
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
private static List<String> readFile() throws IOException {
File file = new File("/some/path/to/file");
return readLines(file, Charset.forName("utf-8"));
}
}

In general, only use static mocking for classes that are beyond your control (e.g. java.io.File). Since DataProvider and readFile are your own, refactor DataProvider into a proper class (i.e. make its methods non-static), pull out readFile into a helper object and then mock that. See this answer https://stackoverflow.com/a/8819339/116509.

Datastore in GAE Testing environment leaks data between JUnit tests

I want to do some automated datastore tests for the Google App Engine locally with Junit.
I have written a class 'Agent.java' with three Strings 'name', 'owner' and 'url'. The class 'Player' is abstract, but does not provide additional attributes.
public class Agent extends Player implements Serializable {
/** to serialize Agent */
private static final long serialVersionUID = -6859912740484191335L;
/** The name of the Agent is the key-element of the agent-class*/
#Id String name;
/** Url to the Agent */
String url;
#Index String owner;
...
Followed by Setters and Getters.
I have copied the 4 needed library from the sdk 1.6.0 to the projects 'war/WEB-INF/lib' folder and included the Junit4 Container.
My test class looks like this:
import static org.junit.Assert.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.logging.Logger;
import org.junit.BeforeClass;
import org.junit.AfterClass;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.Query;
import com.google.appengine.api.datastore.Query.FilterOperator;
import com.google.appengine.tools.development.testing.LocalDatastoreServiceTestConfig;
import com.google.appengine.tools.development.testing.LocalServiceTestHelper;
import com.google.code.twig.annotation.AnnotationObjectDatastore;
public class AgentContrTest {
private static final Logger log = Logger.getLogger("AgentContrTest.class");
private static UserController uc;
private static GameController gc;
private static AgentController ac;
private static final LocalServiceTestHelper helper =
new LocalServiceTestHelper(new LocalDatastoreServiceTestConfig());
private AnnotationObjectDatastore datastore = new AnnotationObjectDatastore(false);
#BeforeClass
public static void setUpOnce() {
gc = GameController.getInstance();
uc = UserController.getInstance();
ac = AgentController.getInstance();
}
#Before
public void setUp() {
helper.setUp();
try {
uc.register("userForTest", "test", "test#gmail.de", false);
}
catch (NameExistsException ne) {
}
catch (EmailFormatException ee) {
}
}
#After
public void tearDown() {
helper.tearDown();
}
// Testing the raising of NameExistsException in createAgent(String name, String url, String owner)
#Test(expected=NameExistsException.class)
public void testCreateAgentExc1() throws NameExistsException {
Agent ag1 = ac.createAgent("Agent1", "www.agent1.com", "Owner1");
Agent ag2 = ac.createAgent("Agent1", "www.agent2.com", "Owner2");
}
// Testing getAgents()
#Test
public void testGetAgents1() throws NameExistsException {
datastore.disassociateAll();
ArrayList<Agent> agents1 = ac.getAgents();
ac.createAgent("Agent1", "www.agent1.com", "Owner1");
ac.createAgent("Agent2", "www.agent2.com", "Owner2");
ac.createAgent("Agent3", "www.agent3.com", "userForTest");
ArrayList<Agent> agents2 = ac.getAgents();
assertTrue(agents1.size()==0);
assertTrue(agents2.size()==3);
datastore.disassociateAll();
}
// Testing getAgents(String user)
#Test
public void testGetAgents2() throws NameExistsException {
ArrayList<Agent> agents = ac.getAgents();
assertTrue(agents.size()==0);
datastore.disassociateAll();
ac.createAgent("Agent1", "www.agent1.com", "Owner1");
ac.createAgent("Agent2", "www.agent2.com", "Owner2");
ac.createAgent("Agent3", "www.agent3.com", "userForTest");
ArrayList<Agent> agents2 = ac.getAgents("userForTest");
assertTrue(agents2.size()==1);
}
These are the functions in my AgentController that I am testing:
public ArrayList<Agent> getAgents(String user) {
ArrayList<Agent> agents = new ArrayList<Agent>();
Iterator<Agent> agentIterator = datastore.find().type(Agent.class)
.addFilter("owner", FilterOperator.EQUAL, user)
.now();
while (agentIterator.hasNext()) {
agents.add(agentIterator.next());
}
return agents;
}
public Agent createAgent(String name, String url, String owner) throws NameExistsException {
Agent agent = datastore.load(Agent.class, name);
if (agent != null)
throw new NameExistsException();
agent = new Agent();
agent.setName(name);
agent.setUrl(url);
agent.setOwner(owner);
datastore.store(agent);
return agent;
}
The testCreateAgentExc1 is working just fine. But the testGetAgents2() is throwing a NameExistsException, which it should not do. If i rename the agents in this test to 'Agent4' to 'Agent6' it is working just fine.
Due to 'http://code.google.com/intl/de-DE/appengine/docs/java/tools/localunittesting.html'
the Datastore should delete all data between the tests, so the NameExistsException should not be raised.

You are not resetting your datastore object between tests. I'm not sure how twig works, but it (or its configuration) is the cause of the leak.

I don't have experience in testing GAE, but there's one difference between your code and the code on Google's page.
You're using a class variable
private static final LocalServiceTestHelper helper
= new LocalServiceTestHelper(new LocalDatastoreServiceTestConfig());
whereas Google uses a field
private final LocalServiceTestHelper helper
= new LocalServiceTestHelper(new LocalDatastoreServiceTestConfig());