sigonasr2/tdd-mortgage-lender
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Implement core features

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Joshua Sigona 2020-08-06 03:52:59 +09:00
commit aabda6aafb
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3
bin/.gitignore vendored Normal file
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/main/
/test/
/default/

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plugins {
id 'org.springframework.boot' version '2.3.1.RELEASE'
id 'io.spring.dependency-management' version '1.0.9.RELEASE'
id 'java'
}
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
testImplementation('org.springframework.boot:spring-boot-starter-test') {
exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
}
compile('org.springframework.boot:spring-boot-starter-data-jpa:2.0.0.RELEASE')
runtime('mysql:mysql-connector-java:8.0.21')
}
test {
useJUnitPlatform()
}

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gradle/wrapper/gradle-wrapper.properties vendored Normal file
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distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-bin.zip
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists

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gradlew vendored Normal file
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#!/usr/bin/env sh
#
# Copyright 2015 the original author or authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
##############################################################################
##
## Gradle start up script for UN*X
##
##############################################################################
# Attempt to set APP_HOME
# Resolve links: $0 may be a link
PRG="$0"
# Need this for relative symlinks.
while [ -h "$PRG" ] ; do
ls=`ls -ld "$PRG"`
link=`expr "$ls" : '.*-> \(.*\)$'`
if expr "$link" : '/.*' > /dev/null; then
PRG="$link"
else
PRG=`dirname "$PRG"`"/$link"
fi
done
SAVED="`pwd`"
cd "`dirname \"$PRG\"`/" >/dev/null
APP_HOME="`pwd -P`"
cd "$SAVED" >/dev/null
APP_NAME="Gradle"
APP_BASE_NAME=`basename "$0"`
# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
# Use the maximum available, or set MAX_FD != -1 to use that value.
MAX_FD="maximum"
warn () {
echo "$*"
}
die () {
echo
echo "$*"
echo
exit 1
}
# OS specific support (must be 'true' or 'false').
cygwin=false
msys=false
darwin=false
nonstop=false
case "`uname`" in
CYGWIN* )
cygwin=true
;;
Darwin* )
darwin=true
;;
MINGW* )
msys=true
;;
NONSTOP* )
nonstop=true
;;
esac
CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
# Determine the Java command to use to start the JVM.
if [ -n "$JAVA_HOME" ] ; then
if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
# IBM's JDK on AIX uses strange locations for the executables
JAVACMD="$JAVA_HOME/jre/sh/java"
else
JAVACMD="$JAVA_HOME/bin/java"
fi
if [ ! -x "$JAVACMD" ] ; then
die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi
else
JAVACMD="java"
which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi
# Increase the maximum file descriptors if we can.
if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
MAX_FD_LIMIT=`ulimit -H -n`
if [ $? -eq 0 ] ; then
if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
MAX_FD="$MAX_FD_LIMIT"
fi
ulimit -n $MAX_FD
if [ $? -ne 0 ] ; then
warn "Could not set maximum file descriptor limit: $MAX_FD"
fi
else
warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
fi
fi
# For Darwin, add options to specify how the application appears in the dock
if $darwin; then
GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
fi
# For Cygwin or MSYS, switch paths to Windows format before running java
if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
APP_HOME=`cygpath --path --mixed "$APP_HOME"`
CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
JAVACMD=`cygpath --unix "$JAVACMD"`
# We build the pattern for arguments to be converted via cygpath
ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
SEP=""
for dir in $ROOTDIRSRAW ; do
ROOTDIRS="$ROOTDIRS$SEP$dir"
SEP="|"
done
OURCYGPATTERN="(^($ROOTDIRS))"
# Add a user-defined pattern to the cygpath arguments
if [ "$GRADLE_CYGPATTERN" != "" ] ; then
OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
fi
# Now convert the arguments - kludge to limit ourselves to /bin/sh
i=0
for arg in "$@" ; do
CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option
if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition
eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
else
eval `echo args$i`="\"$arg\""
fi
i=`expr $i + 1`
done
case $i in
0) set -- ;;
1) set -- "$args0" ;;
2) set -- "$args0" "$args1" ;;
3) set -- "$args0" "$args1" "$args2" ;;
4) set -- "$args0" "$args1" "$args2" "$args3" ;;
5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
esac
fi
# Escape application args
save () {
for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
echo " "
}
APP_ARGS=`save "$@"`
# Collect all arguments for the java command, following the shell quoting and substitution rules
eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
exec "$JAVACMD" "$@"

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@rem
@rem Copyright 2015 the original author or authors.
@rem
@rem Licensed under the Apache License, Version 2.0 (the "License");
@rem you may not use this file except in compliance with the License.
@rem You may obtain a copy of the License at
@rem
@rem https://www.apache.org/licenses/LICENSE-2.0
@rem
@rem Unless required by applicable law or agreed to in writing, software
@rem distributed under the License is distributed on an "AS IS" BASIS,
@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@rem See the License for the specific language governing permissions and
@rem limitations under the License.
@rem
@if "%DEBUG%" == "" @echo off
@rem ##########################################################################
@rem
@rem Gradle startup script for Windows
@rem
@rem ##########################################################################
@rem Set local scope for the variables with windows NT shell
if "%OS%"=="Windows_NT" setlocal
set DIRNAME=%~dp0
if "%DIRNAME%" == "" set DIRNAME=.
set APP_BASE_NAME=%~n0
set APP_HOME=%DIRNAME%
@rem Resolve any "." and ".." in APP_HOME to make it shorter.
for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome
set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if "%ERRORLEVEL%" == "0" goto init
echo.
echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.
goto fail
:findJavaFromJavaHome
set JAVA_HOME=%JAVA_HOME:"=%
set JAVA_EXE=%JAVA_HOME%/bin/java.exe
if exist "%JAVA_EXE%" goto init
echo.
echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.
goto fail
:init
@rem Get command-line arguments, handling Windows variants
if not "%OS%" == "Windows_NT" goto win9xME_args
:win9xME_args
@rem Slurp the command line arguments.
set CMD_LINE_ARGS=
set _SKIP=2
:win9xME_args_slurp
if "x%~1" == "x" goto execute
set CMD_LINE_ARGS=%*
:execute
@rem Setup the command line
set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
@rem Execute Gradle
"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
:end
@rem End local scope for the variables with windows NT shell
if "%ERRORLEVEL%"=="0" goto mainEnd
:fail
rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
rem the _cmd.exe /c_ return code!
if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
exit /b 1
:mainEnd
if "%OS%"=="Windows_NT" endlocal
:omega

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settings.gradle Normal file
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rootProject.name = 'tdd-mortgage-lender'

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src/main/java/com/example/demo/Lender.java Normal file
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package com.example.demo;
public class Lender {
long funds=0l;
public long getAvailableFunds() {
return funds;
}
public void addFunds(long amt) {
if (amt<=0) {
throw new IllegalArgumentException("Amount added must be greater than zero.");
} else {
funds=Math.addExact(funds, amt);
}
}
public boolean checkRequest(LoanApplicant applicant) {
return applicant.getRequestedAmount()<=funds;
}
public double calculateMonthlyPayment(long principal,float annualRate,int numPayments) {
return Math.round(((principal*((annualRate/12)*Math.pow((1+annualRate/12),numPayments)))/(Math.pow(1+(annualRate/12),numPayments)-1)*100))/100d;
}
public boolean isGoodLoanCandidate(LoanApplicant applicant) {
if (applicant.getMonthlyGrossIncome()<=0) {
return false;
}
return applicant.getCreditScore()>=620&&funds>=applicant.getRequestedAmount()*0.25&&(double)applicant.getMonthlyDebtLoad()/applicant.getMonthlyGrossIncome()<0.36;
}
}

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src/main/java/com/example/demo/LoanApplicant.java Normal file
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package com.example.demo;
final class LoanApplicant {
private final int creditScore;
private final int downPayment;
private final int monthlyDebtLoad;
private final int monthlyGrossIncome;
private final long requestedAmount;
LoanApplicant(final int downPayment, final long requestedAmount, final int monthlyGrossIncome, final int monthlyDebtLoad, final int creditScore) {
this.downPayment = downPayment;
this.requestedAmount = requestedAmount;
this.monthlyGrossIncome = monthlyGrossIncome;
this.monthlyDebtLoad = monthlyDebtLoad;
this.creditScore = creditScore;
}
int getCreditScore() {
return creditScore;
}
int getDownPayment() {
return downPayment;
}
int getMonthlyDebtLoad() {
return monthlyDebtLoad;
}
int getMonthlyGrossIncome() {
return monthlyGrossIncome;
}
long getRequestedAmount() {
return requestedAmount;
}
}

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src/main/resources/application.properties Normal file
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spring.datasource.url=jdbc:mysql://localhost/playground?serverTimezone=UTC
spring.datasource.username=sigonasr2
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update
spring.jpa.database-platform=org.hibernate.dialect.MySQL8Dialect

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src/test/java/com/example/demo/LenderTest.java Normal file
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package com.example.demo;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;
final class LenderTest {
@Test
void getAvailableFundsReturnsZeroByDefault() {
//Setup
final Lender lender = new Lender();
final long expected = 0L;
//Exercise
final long actual = lender.getAvailableFunds();
//Assert
assertEquals(expected,actual
,"Test initializing funds.");
//Teardown
}
@Test
void addFundsThrowsAnExceptionForZero(){
//Setup
final Lender lender = new Lender();
final String expected = "Amount added must be greater than zero.";
//Exercise
final Exception actual = assertThrows(IllegalArgumentException.class,
() -> lender.addFunds(0L));
//Assert
assertEquals(expected,actual.getMessage()
,"Test increasing by less than 1");
}
@Test
void addFundsIncreasesAvailableFundsByOne(){
//Setup
final Lender lender = new Lender();
final long expected = 1L;
//Exercise
lender.addFunds(expected);
final long actual = lender.getAvailableFunds();
//Assert
assertEquals(expected,actual
,"Increase available funds by 1");
}
@Test
void addFundsThrowsAnExceptionForNegativeValue(){
//Setup
final Lender lender = new Lender();
final String expected = "Amount added must be greater than zero.";
//Exercise
final Exception actual = assertThrows(IllegalArgumentException.class,
() -> lender.addFunds(Long.MIN_VALUE));
//Assert
assertEquals(expected,actual.getMessage()
,"Test increasing by less than 1");
}
@Test
void addFundsIncreasesAvailableFundsByTwo(){
//Setup
final Lender lender = new Lender();
final long expected = 2L;
//Exercise
lender.addFunds(expected);
final long actual = lender.getAvailableFunds();
//Assert
assertEquals(expected,actual
,"Test Increasing available funds");
}
@Test
void addFundsIncreasesAvailableFundsByThreeThenFour(){
//Setup
final Lender lender = new Lender();
final long expected = 7L;
//Exercise
lender.addFunds(3L);
lender.addFunds(4L);
final long actual = lender.getAvailableFunds();
//Assert
assertEquals(expected,actual
,"Test Increasing available funds multiple times");
}
@Test
void addFundsThrowExceptionIfOverflowWillHappen(){
//Setup
final Lender lender = new Lender();
lender.addFunds(Long.MAX_VALUE);
final String expected = "long overflow";
//Exercise
final Exception actual = assertThrows(ArithmeticException.class,
() -> lender.addFunds(1L));
//Assert
assertEquals(expected,actual.getMessage()
,"Prevent overflow errors");
}
@Test
void rejectHighLoanAmounts(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,7900l,81829,0,860);
//Assert
assertEquals(false,lender.checkRequest(applicant)
,"Deny applicants that offer high loan amounts");
}
@Test
void acceptLowLoanAmounts(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,81829,0,860);
//Assert
assertEquals(true,lender.checkRequest(applicant)
,"Accept applicants that offer low loan amounts");
}
@Test
void calculateMonthlyMortgagePayment(){
//Setup
final Lender lender = new Lender();
//monthlyPayment = principal * ((interestRate/12) * (1+(interestRate/12))^numberOfPayments) / ((1 + (interestRate/12))^numberOfPayments - 1)
long principal = 250000l;
float annualRate = 0.04f;
int numPayments = 360;
//Assert
assertEquals(1193.54d,lender.calculateMonthlyPayment(principal,annualRate,numPayments)
,"Calculate Monthly Mortgage Payments properly");
}
@Test
void isGoodLoanCandidate(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,81829,0,860);
//Assert
assertEquals(true,lender.isGoodLoanCandidate(applicant)
,"Accept good Debt-to-Income applicants");
}
@Test
void denyRequestedMortageDebtToIncomeTooHigh(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,400,200,860);
//Assert
assertEquals(false,lender.isGoodLoanCandidate(applicant)
,"Deny bad Debt-to-Income applicants");
}
@Test
void denyRequestedMortageDebtToIncomeTooHigh2(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,1000,360,860);
//Assert
assertEquals(false,lender.isGoodLoanCandidate(applicant)
,"Deny bad Debt-to-Income applicants");
}
@Test
void acceptRequestedMortageDebtToIncomeGoodEnough(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,1000,359,860);
//Assert
assertEquals(true,lender.isGoodLoanCandidate(applicant)
,"Accept good Debt-to-Income applicants");
}
@Test
void acceptRequestedMortageDebtCreditScoreGoodEnough(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,1000,359,620);
//Assert
assertEquals(true,lender.isGoodLoanCandidate(applicant)
,"Accept good credit scores");
}
@Test
void denyRequestedMortageDebtCreditScoreTooLow(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,3200l,1000,359,619);
//Assert
assertEquals(false,lender.isGoodLoanCandidate(applicant)
,"Deny credit scores that are too low");
}
@Test
void denyRequestedMortageDebtAmountSavedTooLow(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,12801l,1000,359,620);
//Assert
assertEquals(false,lender.isGoodLoanCandidate(applicant)
,"Deny Amount Saved too low.");
}
@Test
void acceptRequestedMortageDebtAmountSavedHighEnough(){
//Setup
final Lender lender = new Lender();
lender.addFunds(3200l);
LoanApplicant applicant = new LoanApplicant(640000,12800l,1000,359,620);
//Assert
assertEquals(true,lender.isGoodLoanCandidate(applicant)
,"Accept Amount Saved is 25% or more of requested amount.");
}
}