Quick Prep Java Interview Archives | Page 28 of 28

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Unit Testing Servlet filter with Mockito

This assumes that you have gone through the basic JUnit & Mockito tutorials. Here is test class to “Unit Testing Servlet Filter”. The “HttpServletRequest“, “HttpServletResponse“, “FilterChain“, etc are mocked with Mockito. The Spring also provides classes like “

…

Unit testing Spring Transaction Management

Unit testing Spring transaction management –> i.e. commit & rollback scenarios as shown below. On a separate post, will do an integration test for the Spring transaction manager. The test class defines the transactional boundaries. Transaction Commit scenario

package com.myapp.dao;

import java.util.List;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.transaction.AfterTransaction;
import org.springframework.test.context.transaction.BeforeTransaction;
import org.springframework.test.context.transaction.TransactionConfiguration;
import org.springframework.transaction.annotation.Transactional;

import com.myapp.config.AppConfig;
import com.myapp.config.AppTestConfig;
import com.myapp.model.EventControl;
import com.myapp.model.common.MyAppType;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = { AppConfig.class, AppTestConfig.class })
@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)
public class EventControlDaoTxnCommitTest extends AbstractTransactionalJUnit4SpringContextTests {

    @Autowired
    EventControlDao eventControlDao;

    private static final String USER_ID = "AYYYY";
    private static final String EVENT_DATE = "20/10/2015";
    

    @BeforeTransaction
    public void beforeTransaction() {
        testEventControl(0);
    }

    @AfterTransaction
    public void afterTransaction() {
        testEventControl(1);
    }

    @Test
    @Transactional
    public void testEventControlCommit() {
        eventControlDao.create(getFsEventControl(USER_ID, EVENT_DATE));
    }
    
    private void testEventControl(int count) {
        List<EventControl> listEventControl = eventControlDao.findByValue(getPendingEventControl());
        Assert.assertEquals(count, listEventControl.size());
    }

    private EventControl getFsEventControl(String client, String eventKey) {
        EventControl fsEventControl = new EventControl();
        fsEventControl.setEventType(EventControl.EventType.BASIC);
        fsEventControl.setEventKey(EventControl.EventKey.USER_DATE);
        fsEventControl.setEventValue1(client);
        fsEventControl.setEventValue2(EVENT_DATE);
        return fsEventControl;
    }

    private EventControl getPendingEventControl() {
        EventControl ec = new EventControl();
        ec.setEventType(EventControl.EventType.BASIC);
        ec.setEventValue1(USER_ID);
        ec.setEventValue2(EVENT_DATE);
        ec.setEventStatus(EventControl.EventStatus.PENDING);
        return ec;
    }
}

package com.myapp.dao;

import java.util.List;

import org.junit.Assert;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.SpringApplicationConfiguration;

import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import org.springframework.test.context.transaction.AfterTransaction;

import org.springframework.test.context.transaction.BeforeTransaction;

import org.springframework.test.context.transaction.TransactionConfiguration;

import org.springframework.transaction.annotation.Transactional;

import com.myapp.config.AppConfig;

import com.myapp.config.AppTestConfig;

import com.myapp.model.EventControl;

import com.myapp.model.common.MyAppType;

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(classes = { AppConfig.class, AppTestConfig.class })

@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)

public class EventControlDaoTxnCommitTest extends AbstractTransactionalJUnit4SpringContextTests {

@Autowired

EventControlDao eventControlDao;

private static final String USER_ID = "AYYYY";

private static final String EVENT_DATE = "20/10/2015";

@BeforeTransaction

public void beforeTransaction() {

testEventControl(0);

}

@AfterTransaction

public void afterTransaction() {

testEventControl(1);

}

@Test

@Transactional

public void testEventControlCommit() {

eventControlDao.create(getFsEventControl(USER_ID, EVENT_DATE));

}

private void testEventControl(int count) {

List<EventControl> listEventControl = eventControlDao.findByValue(getPendingEventControl());

Assert.assertEquals(count, listEventControl.size());

}

private EventControl getFsEventControl(String client, String eventKey) {

EventControl fsEventControl = new EventControl();

fsEventControl.setEventType(EventControl.EventType.BASIC);

fsEventControl.setEventKey(EventControl.EventKey.USER_DATE);

fsEventControl.setEventValue1(client);

fsEventControl.setEventValue2(EVENT_DATE);

return fsEventControl;

}

private EventControl getPendingEventControl() {

EventControl ec = new EventControl();

ec.setEventType(EventControl.EventType.BASIC);

ec.setEventValue1(USER_ID);

ec.setEventValue2(EVENT_DATE);

ec.setEventStatus(EventControl.EventStatus.PENDING);

return ec;

}

Transaction Rolback scenario

package com.myapp.dao;

import java.util.List;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.transaction.AfterTransaction;
import org.springframework.test.context.transaction.BeforeTransaction;
import org.springframework.test.context.transaction.TransactionConfiguration;
import org.springframework.transaction.annotation.Transactional;

importcom.myappconfig.AppConfig;
importcom.myappconfig.AppTestConfig;
importcom.myappmodel.EventControl;
import com.myapp.model.commonEventType;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = { AppConfig.class, AppTestConfig.class })
@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)
public class EventControlDaoTxnRollbackTest extends AbstractTransactionalJUnit4SpringContextTests {

    @Autowired
    EventControlDao eventControlDao;

    private static final String USER_ID = "AXXX";
    private static final String EVENT_DATE = "20/10/2015";

    @BeforeTransaction
    public void beforeTransaction() {
        testEventControl(0);
    }

    @AfterTransaction
    public void afterTransaction() {
        testEventControl(0);
    }

    @Test
    @Transactional
    @Rollback(true)
    public void testEventControlRollback() {
        eventControlDao.create(getFsEventControl(USER_ID, EVENT_DATE));
    }
    
    private void testEventControl(int count) {
        List<EventControl> listEventControl = eventControlDao.findByValue(getPendingEventControl());
        Assert.assertEquals(count, listEventControl.size());
    }

    private EventControl getFsEventControl(String clientId, String fsDate) {
        EventControl fsEventControl = new EventControl();
        fsEventControl.setEventType(EventControl.EventType.BASIC);
        fsEventControl.setEventKey(EventControl.EventKey.USER_DATE);
        fsEventControl.setEventValue1(clientId);
        fsEventControl.setEventValue2(fsDate);
        fsEventControl.setEventStatus(EventControl.EventStatus.PENDING);
        return fsEventControl;
    }

    private EventControl getPendingEventControl() {
        EventControl ec = new EventControl();
        ec.setEventType(EventControl.EventType.BASIC);
        ec.setEventValue1(USER_ID);
        ec.setEventValue2(EVENT_DATE);
        ec.setEventStatus(EventControl.EventStatus.PENDING);
        return ec;
    }
}

package com.myapp.dao;

import java.util.List;

import org.junit.Assert;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.SpringApplicationConfiguration;

import org.springframework.test.annotation.Rollback;

import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;

import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import org.springframework.test.context.transaction.AfterTransaction;

import org.springframework.test.context.transaction.BeforeTransaction;

import org.springframework.test.context.transaction.TransactionConfiguration;

import org.springframework.transaction.annotation.Transactional;

importcom.myappconfig.AppConfig;

importcom.myappconfig.AppTestConfig;

importcom.myappmodel.EventControl;

import com.myapp.model.commonEventType;

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(classes = { AppConfig.class, AppTestConfig.class })

@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)

public class EventControlDaoTxnRollbackTest extends AbstractTransactionalJUnit4SpringContextTests {

@Autowired

EventControlDao eventControlDao;

private static final String USER_ID = "AXXX";

private static final String EVENT_DATE = "20/10/2015";

@BeforeTransaction

public void beforeTransaction() {

testEventControl(0);

}

@AfterTransaction

public void afterTransaction() {

testEventControl(0);

}

@Test

@Transactional

@Rollback(true)

public void testEventControlRollback() {

eventControlDao.create(getFsEventControl(USER_ID, EVENT_DATE));

}

private void testEventControl(int count) {

List<EventControl> listEventControl = eventControlDao.findByValue(getPendingEventControl());

Assert.assertEquals(count, listEventControl.size());

}

private EventControl getFsEventControl(String clientId, String fsDate) {

EventControl fsEventControl = new EventControl();

fsEventControl.setEventType(EventControl.EventType.BASIC);

fsEventControl.setEventKey(EventControl.EventKey.USER_DATE);

fsEventControl.setEventValue1(clientId);

fsEventControl.setEventValue2(fsDate);

fsEventControl.setEventStatus(EventControl.EventStatus.PENDING);

return fsEventControl;

}

private EventControl getPendingEventControl() {

EventControl ec = new EventControl();

ec.setEventType(EventControl.EventType.BASIC);

ec.setEventValue1(USER_ID);

ec.setEventValue2(EVENT_DATE);

ec.setEventStatus(EventControl.EventStatus.PENDING);

return ec;

}

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What is wrong with this Java code? Heap Vs Stack, Thread safety & Synchronized

This post covers must know Java Multithreading basics – Heap Vs Stack, Thread-safety & Synchronization. When you have a multithreaded Java application, you need to code in a thread-safe manner. Java interviewers may ask you to detect thread-safety issues as discussed in here.

1.What is wrong with the following code?…

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Working with a given input string & character processing

Q. Complete the following StringProcessingImpl.java” class ….. so that the unit tests shown below pass?

package com.passing.unittests;

public class StringProcessingImpl implements StringProcessing {

    public int getWordCount(String input) {
        return 0;
    }

    public int getCapitalsCount(String input) {
        return 0;
    }

    public String encode(String input) {
        return null;
    }

    public String removeRepeatedConsecutiveCharacters(String string, int consecutiveAllowedCount) {
        return null;
    }

    public String replaceRepeatedWordsWith(String input, String... replaceWord) {
        return null;
    }
}

package com.passing.unittests;

public class StringProcessingImpl implements StringProcessing {

public int getWordCount(String input) {

return 0;

}

public int getCapitalsCount(String input) {

return 0;

}

public String encode(String input) {

return null;

}

public String removeRepeatedConsecutiveCharacters(String string, int consecutiveAllowedCount) {

return null;

}

public String replaceRepeatedWordsWith(String input, String... replaceWord) {

return null;

}

Unit test

package com.passing.unittests;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;


public class StringProcessingTest {

    private static final String INPUT = "Logic takes you from A to B, but imagination takes you everywhere";

    private StringProcessing sp = null;

    @Before
    public void init() {
        sp = new StringProcessingImpl();
    }

    @Test
    public void testgetWordCount() {
        Assert.assertEquals("Wrong", 12, sp.getWordCount(INPUT));
    }

    @Test
    public void testGetCapitalsCount() {
        Assert.assertEquals("Wrong", 3, sp.getCapitalsCount(INPUT));
    }

    @Test
    public void testEncode() {
        Assert.assertEquals("Wrong", "Ybtvp gnxrf lbh sebz N gb O, ohg vzntvangvba gnxrf lbh rireljurer",
            sp.encode(INPUT));
    }

    @Test
    public void testRemoveRepeatedConsecutiveCharacters() {
        Assert.assertEquals("Wrong", "blah Blah Blah",
            sp.removeRepeatedConsecutiveCharacters("blaah Blaaaah Blahhhh", 1));
        Assert.assertEquals("Wrong", "blaah Blaah Blahh",
            sp.removeRepeatedConsecutiveCharacters("blaah Blaaaah Blahhhh",2));
    }
    
    @Test
    public void testReplaceRepeatedWords() {
        Assert.assertEquals("Wrong", "Logic takes you from A to B, but imagination recognises us everywhere",
            sp.replaceRepeatedWordsWith (INPUT, "recognises", "us")); //takes -> recognises , you -> us
    }

}

package com.passing.unittests;

import org.junit.Assert;

import org.junit.Before;

import org.junit.Test;

public class StringProcessingTest {

private static final String INPUT = "Logic takes you from A to B, but imagination takes you everywhere";

private StringProcessing sp = null;

@Before

public void init() {

sp = new StringProcessingImpl();

}

@Test

public void testgetWordCount() {

Assert.assertEquals("Wrong", 12, sp.getWordCount(INPUT));

}

@Test

public void testGetCapitalsCount() {

Assert.assertEquals("Wrong", 3, sp.getCapitalsCount(INPUT));

}

@Test

public void testEncode() {

Assert.assertEquals("Wrong", "Ybtvp gnxrf lbh sebz N gb O, ohg vzntvangvba gnxrf lbh rireljurer",

sp.encode(INPUT));

}

@Test

public void testRemoveRepeatedConsecutiveCharacters() {

Assert.assertEquals("Wrong", "blah Blah Blah",

sp.removeRepeatedConsecutiveCharacters("blaah Blaaaah Blahhhh", 1));

Assert.assertEquals("Wrong", "blaah Blaah Blahh",

sp.removeRepeatedConsecutiveCharacters("blaah Blaaaah Blahhhh",2));

}

@Test

public void testReplaceRepeatedWords() {

Assert.assertEquals("Wrong", "Logic takes you from A to B, but imagination recognises us everywhere",

sp.replaceRepeatedWordsWith (INPUT, "recognises", "us")); //takes -> recognises , you -> us

}

Solution

package com.passing.unittests;

import java.util.HashSet;
import java.util.Set;

public class StringProcessingImpl implements StringProcessing {

    public int getWordCount(String input) {
        if(input == null || input.length() == 0){
            return 0;
        }
        
        String[] split = input.split("\\s+"); // regex to split on 1 or more spaces
        
        return split.length;
    }

    public int getCapitalsCount(String input) {
        if(input == null || input.length() == 0){
            return 0;
        }
        
        int counter = 0;
        
        char[] charArray = input.toCharArray();
        for (char c : charArray) {
            if(Character.isUpperCase(c)) {
                counter++;
            }
        }
        
        return counter;
    }

    /**
     *  System.out.println((int) ('Y' - 'L')); //13
        System.out.println((int) ('N' - 'A')); //13
     */
    public String encode(String input) {
        
        if(input == null || input.length() == 0){
            return input;
        }
        
        StringBuilder sb = new StringBuilder();

        for (char c : input.toCharArray()) {
            
            if (c >= 'a' && c <= 'm') {
               c += 13;
            }
            else if (c >= 'A' && c <= 'M'){
                c += 13;
            }
            else if (c >= 'n' && c <= 'z'){
                c -= 13;
            }
            else if (c >= 'M' && c <= 'Z'){
                c -= 13;
            }

            //System.out.println(c + " is " + n);
            sb.append(c);
        }

        return sb.toString();
    }

    public String removeRepeatedConsecutiveCharacters(String input, int consecutiveAllowedCount) {
        if(input == null || input.length() == 0){
            return input;
        }
        
        char[] charArray = input.toCharArray();
        char prev_c = ' ', cons_char_seen_count = 0;
        
        StringBuilder sb = new StringBuilder(input.length());
        
        for (char current_c : charArray) {
            if(current_c == prev_c){
                ++cons_char_seen_count;
            }
            else {
                cons_char_seen_count = 0; // resetting the count
                prev_c = current_c;
            }
            
            if(cons_char_seen_count < consecutiveAllowedCount){
              sb.append(current_c);   
            }
        }
        
        return sb.toString();
    }

    /**
     *  varargs is used with ...
     */
    public String replaceRepeatedWordsWith(String input, String... replaceWord) {
        if(input == null || input.length() == 0){
            return input;
        }
        
        Set<String> processedWords = new HashSet<String>(20);
        StringBuilder sb = new StringBuilder(50);
        
        int index = 0;
        
        for (String word : input.split("\\s+")) {
            if(!processedWords.contains(word)){
                sb.append(word + " ");
                processedWords.add(word);
            } else {
                sb.append(replaceWord[index] + " ");
                index++;
            }
        }
        
        return sb.toString().trim();
    }
}

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package com.passing.unittests;

import java.util.HashSet;

import java.util.Set;

public class StringProcessingImpl implements StringProcessing {

public int getWordCount(String input) {

if(input == null || input.length() == 0){

return 0;

}

String[] split = input.split("\\s+"); // regex to split on 1 or more spaces

return split.length;

}

public int getCapitalsCount(String input) {

if(input == null || input.length() == 0){

return 0;

}

int counter = 0;

char[] charArray = input.toCharArray();

for (char c : charArray) {

if(Character.isUpperCase(c)) {

counter++;

}

return counter;

}

/**

* System.out.println((int) ('Y' - 'L')); //13

System.out.println((int) ('N' - 'A')); //13

public String encode(String input) {

if(input == null || input.length() == 0){

return input;

}

StringBuilder sb = new StringBuilder();

for (char c : input.toCharArray()) {

if (c >= 'a' && c <= 'm') {

c += 13;

}

else if (c >= 'A' && c <= 'M'){

c += 13;

}

else if (c >= 'n' && c <= 'z'){

c -= 13;

}

else if (c >= 'M' && c <= 'Z'){

c -= 13;

}

//System.out.println(c + " is " + n);

sb.append(c);

}

return sb.toString();

}

public String removeRepeatedConsecutiveCharacters(String input, int consecutiveAllowedCount) {

if(input == null || input.length() == 0){

return input;

}

char[] charArray = input.toCharArray();

char prev_c = ' ', cons_char_seen_count = 0;

StringBuilder sb = new StringBuilder(input.length());

for (char current_c : charArray) {

if(current_c == prev_c){

++cons_char_seen_count;

}

else {

cons_char_seen_count = 0; // resetting the count

prev_c = current_c;

}

if(cons_char_seen_count < consecutiveAllowedCount){

sb.append(current_c);

}

return sb.toString();

}

/**

* varargs is used with ...

public String replaceRepeatedWordsWith(String input, String... replaceWord) {

if(input == null || input.length() == 0){

return input;

}

Set<String> processedWords = new HashSet<String>(20);

StringBuilder sb = new StringBuilder(50);

int index = 0;

for (String word : input.split("\\s+")) {

if(!processedWords.contains(word)){

sb.append(word + " ");

processedWords.add(word);

} else {

sb.append(replaceWord[index] + " ");

index++;

}

return sb.toString().trim();

}

Key points #1. The encode method is using the rot13 encoding that is used for hiding offensive material from accidental viewing, … Read more ›...

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Working with monetary values

Q. Complete the following “MonetaryProcessingImpl.java” class … so that the unit tests shown below pass? Skeleton code

package com.passing.unittests;

public final class Denomination {

    private long _dollarCount;
    private long _50CentCount;
    private long _20CentCount;
    private long _10CentCount;
    private long _5CentCount;

    public Denomination(long _dollarCount, long _50CentCount, 
                       long _20CentCount, long _10CentCount, long _5CentCount) {
        this._dollarCount = _dollarCount;
        this._50CentCount = _50CentCount;
        this._20CentCount = _20CentCount;
        this._10CentCount = _10CentCount;
        this._5CentCount = _5CentCount;
    }
    
    
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (int) (_10CentCount ^ (_10CentCount >>> 32));
        result = prime * result + (int) (_20CentCount ^ (_20CentCount >>> 32));
        result = prime * result + (int) (_50CentCount ^ (_50CentCount >>> 32));
        result = prime * result + (int) (_5CentCount ^ (_5CentCount >>> 32));
        result = prime * result + (int) (_dollarCount ^ (_dollarCount >>> 32));
        return result;
    }


    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Denomination other = (Denomination) obj;
        if (_10CentCount != other._10CentCount)
            return false;
        if (_20CentCount != other._20CentCount)
            return false;
        if (_50CentCount != other._50CentCount)
            return false;
        if (_5CentCount != other._5CentCount)
            return false;
        if (_dollarCount != other._dollarCount)
            return false;
        return true;
    }

    public long get_dollarCount() {
        return _dollarCount;
    }

    public long get_50CentCount() {
        return _50CentCount;
    }

    public long get_20CentCount() {
        return _20CentCount;
    }

    public long get_10CentCount() {
        return _10CentCount;
    }

    public long get_5CentCount() {
        return _5CentCount;
    }  
}

package com.passing.unittests;

public final class Denomination {

private long _dollarCount;

private long _50CentCount;

private long _20CentCount;

private long _10CentCount;

private long _5CentCount;

public Denomination(long _dollarCount, long _50CentCount,

long _20CentCount, long _10CentCount, long _5CentCount) {

this._dollarCount = _dollarCount;

this._50CentCount = _50CentCount;

this._20CentCount = _20CentCount;

this._10CentCount = _10CentCount;

this._5CentCount = _5CentCount;

}

@Override

public int hashCode() {

final int prime = 31;

int result = 1;

result = prime * result + (int) (_10CentCount ^ (_10CentCount >>> 32));

result = prime * result + (int) (_20CentCount ^ (_20CentCount >>> 32));

result = prime * result + (int) (_50CentCount ^ (_50CentCount >>> 32));

result = prime * result + (int) (_5CentCount ^ (_5CentCount >>> 32));

result = prime * result + (int) (_dollarCount ^ (_dollarCount >>> 32));

return result;

}

@Override

public boolean equals(Object obj) {

if (this == obj)

return true;

if (obj == null)

return false;

if (getClass() != obj.getClass())

return false;

Denomination other = (Denomination) obj;

if (_10CentCount != other._10CentCount)

return false;

if (_20CentCount != other._20CentCount)

return false;

if (_50CentCount != other._50CentCount)

return false;

if (_5CentCount != other._5CentCount)

return false;

if (_dollarCount != other._dollarCount)

return false;

return true;

}

public long get_dollarCount() {

return _dollarCount;

}

public long get_50CentCount() {

return _50CentCount;

}

public long get_20CentCount() {

return _20CentCount;

}

public long get_10CentCount() {

return _10CentCount;

}

public long get_5CentCount() {

return _5CentCount;

}

package com.passing.unittests;

import java.math.BigDecimal;
import java.math.RoundingMode;

public interface MonetaryProcessing {
    
    abstract Denomination getDenominations(long amountInCents);
    
    abstract boolean isPositive(BigDecimal amount);

    abstract BigDecimal less(BigDecimal amount, BigDecimal amountToSubtract, boolean ignoreNegativeValue);
    
    abstract BigDecimal divide (BigDecimal input, BigDecimal divisor, RoundingMode roundingMode);
}

package com.passing.unittests;

import java.math.BigDecimal;

import java.math.RoundingMode;

public interface MonetaryProcessing {

abstract Denomination getDenominations(long amountInCents);

abstract boolean isPositive(BigDecimal amount);

abstract BigDecimal less(BigDecimal amount, BigDecimal amountToSubtract, boolean ignoreNegativeValue);

abstract BigDecimal divide (BigDecimal input, BigDecimal divisor, RoundingMode roundingMode);

}

package com.passing.unittests;

import java.math.BigDecimal;
import java.math.RoundingMode;


public class MonetaryProcessingImpl implements MonetaryProcessing {

    public Denomination getDenominations(long amountInCents) {
       return null;
    }

    public boolean isPositive(BigDecimal amount) {
        return false;
    }

    public BigDecimal less(BigDecimal balance, BigDecimal amountToSubtract, boolean ignoreNegativeValue) {
        return null;
    }

    public BigDecimal divide(BigDecimal input, BigDecimal divisor, RoundingMode roundingMode) {
       return null;
    }
   
}

package com.passing.unittests;

import java.math.BigDecimal;

import java.math.RoundingMode;

public class MonetaryProcessingImpl implements MonetaryProcessing {

public Denomination getDenominations(long amountInCents) {

return null;

}

public boolean isPositive(BigDecimal amount) {

return false;

}

public BigDecimal less(BigDecimal balance, BigDecimal amountToSubtract, boolean ignoreNegativeValue) {

return null;

}

public BigDecimal divide(BigDecimal input, BigDecimal divisor, RoundingMode roundingMode) {

return null;

}

The unit test that fails

package com.passing.unittests;

import java.math.BigDecimal;
import java.math.RoundingMode;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

public class MonetaryProcessingTest {

    private MonetaryProcessing mp = null;

    @Before
    public void init() {
        mp = new MonetaryProcessingImpl();
    }

    @Test
    public void testGetDenominations() {
        Denomination denomination = new Denomination(9, 1, 1, 0, 1);
        Assert.assertEquals("Wrong", denomination, mp.getDenominations(975));
    }
    
    @Test(expected=IllegalArgumentException.class)
    public void testNegativeGetDenominations() {
       mp.getDenominations(0);
    }

    
    @Test
    public void testLess() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(875.00),  
            mp.less(BigDecimal.valueOf(900.00), BigDecimal.valueOf(25.00), false)); 
    }
    
    @Test
    public void testLess2() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(-925.00),  
            mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(25.00), false)); 
    }
    
    
    @Test
    public void testLess3() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(-900.00),  
            mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(25.00), true)); 
    }
    
    @Test(expected=IllegalArgumentException.class)
    public void testLessNegativeTest() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(-900.00),  
            mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(-25.00), true)); 
    }
    
    
    @Test
    public void testDevide() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(3.14),  
            mp.divide(BigDecimal.valueOf(22.00), BigDecimal.valueOf(7.00), RoundingMode.HALF_EVEN)); 
    }
    
    
    @Test(expected=IllegalArgumentException.class)
    public void testDevideHegativeTest() {
        Assert.assertEquals("Wrong", BigDecimal.valueOf(3.14),  
            mp.divide(BigDecimal.valueOf(22.00), BigDecimal.valueOf(-7.00), RoundingMode.HALF_EVEN)); 
    }  
}

package com.passing.unittests;

import java.math.BigDecimal;

import java.math.RoundingMode;

import org.junit.Assert;

import org.junit.Before;

import org.junit.Test;

public class MonetaryProcessingTest {

private MonetaryProcessing mp = null;

@Before

public void init() {

mp = new MonetaryProcessingImpl();

}

@Test

public void testGetDenominations() {

Denomination denomination = new Denomination(9, 1, 1, 0, 1);

Assert.assertEquals("Wrong", denomination, mp.getDenominations(975));

}

@Test(expected=IllegalArgumentException.class)

public void testNegativeGetDenominations() {

mp.getDenominations(0);

}

@Test

public void testLess() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(875.00),

mp.less(BigDecimal.valueOf(900.00), BigDecimal.valueOf(25.00), false));

}

@Test

public void testLess2() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(-925.00),

mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(25.00), false));

}

@Test

public void testLess3() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(-900.00),

mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(25.00), true));

}

@Test(expected=IllegalArgumentException.class)

public void testLessNegativeTest() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(-900.00),

mp.less(BigDecimal.valueOf(-900.00), BigDecimal.valueOf(-25.00), true));

}

@Test

public void testDevide() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(3.14),

mp.divide(BigDecimal.valueOf(22.00), BigDecimal.valueOf(7.00), RoundingMode.HALF_EVEN));

}

@Test(expected=IllegalArgumentException.class)

public void testDevideHegativeTest() {

Assert.assertEquals("Wrong", BigDecimal.valueOf(3.14),

mp.divide(BigDecimal.valueOf(22.00), BigDecimal.valueOf(-7.00), RoundingMode.HALF_EVEN));

}

A. Code that passes the test cases

package com.passing.unittests;

import java.math.BigDecimal;
import java.math.RoundingMode;


public class MonetaryProcessingImpl implements MonetaryProcessing {

    /**
     * the comments are for input of 975  cents
     */
    public Denomination getDenominations(long amountInCents) {
        
        if(amountInCents <= 0){
            throw new IllegalArgumentException("Invalid amount in cents: " + amountInCents);
        }
        
       long varDollarCount, var50CentCount, var20CentCount, var10CentCount, var5CentCount = 0;
       long balance = amountInCents;
       
       varDollarCount = balance/100; //9
       balance = balance%100; // 75
       
       var50CentCount = balance/50;   //1
       balance = balance%50; //25
       
       var20CentCount = balance/20; //1 
       balance = balance%20; //5
       
       var10CentCount = balance/10; //0
       balance = balance%10; //5
       
       var5CentCount = balance/5; //1
       balance = balance%5; //0
       
        
       return new Denomination(varDollarCount, var50CentCount, var20CentCount, var10CentCount, var5CentCount);
    }

    public boolean isPositive(BigDecimal amount) {
        return amount != null && amount.signum() == 1;
    }

    public BigDecimal less(BigDecimal balance, BigDecimal amountToSubtract, boolean ignoreNegativeValue) {
        
        if(amountToSubtract != null && amountToSubtract.signum() == -1){
            throw new IllegalArgumentException("Amount to sbtract cannot be -ve: " + amountToSubtract);
        }
        
        if (isPositive(balance) || !ignoreNegativeValue) {
            balance = balance.subtract(amountToSubtract);
        }
        
        return balance;
    }

    public BigDecimal divide(BigDecimal input, BigDecimal divisor, RoundingMode roundingMode) {
       if(input == null || divisor == null){
           throw new IllegalArgumentException("Invalid input");
       }
       
       if (divisor.compareTo(BigDecimal.ZERO) == 0 || divisor.compareTo(BigDecimal.ZERO) == -1){
           throw new IllegalArgumentException("Divisor cannot be zero or negative: " +  divisor);
       }
       
        return input.divide(divisor, 2, roundingMode);
    }  
}

package com.passing.unittests;

import java.math.BigDecimal;

import java.math.RoundingMode;

public class MonetaryProcessingImpl implements MonetaryProcessing {

/**

* the comments are for input of 975 cents

public Denomination getDenominations(long amountInCents) {

if(amountInCents <= 0){

throw new IllegalArgumentException("Invalid amount in cents: " + amountInCents);

}

long varDollarCount, var50CentCount, var20CentCount, var10CentCount, var5CentCount = 0;

long balance = amountInCents;

varDollarCount = balance/100; //9

balance = balance%100; // 75

var50CentCount = balance/50; //1

balance = balance%50; //25

var20CentCount = balance/20; //1

balance = balance%20; //5

var10CentCount = balance/10; //0

balance = balance%10; //5

var5CentCount = balance/5; //1

balance = balance%5; //0

return new Denomination(varDollarCount, var50CentCount, var20CentCount, var10CentCount, var5CentCount);

}

public boolean isPositive(BigDecimal amount) {

return amount != null && amount.signum() == 1;

}

public BigDecimal less(BigDecimal balance, BigDecimal amountToSubtract, boolean ignoreNegativeValue) {

if(amountToSubtract != null && amountToSubtract.signum() == -1){

throw new IllegalArgumentException("Amount to sbtract cannot be -ve: " + amountToSubtract);

}

if (isPositive(balance) || !ignoreNegativeValue) {

balance = balance.subtract(amountToSubtract);

}

return balance;

}

public BigDecimal divide(BigDecimal input, BigDecimal divisor, RoundingMode roundingMode) {

if(input == null || divisor == null){

throw new IllegalArgumentException("Invalid input");

}

if (divisor.compareTo(BigDecimal.ZERO) == 0 || divisor.compareTo(BigDecimal.ZERO) == -1){

throw new IllegalArgumentException("Divisor cannot be zero or negative: " + divisor);

}

return input.divide(divisor, 2, roundingMode);

}

Key Points Take note that test cases test for exceptions being thrown as well. … Read...

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