update;

src/main/java/rocks/zipcode/quiz3a/objectorientation/account/BankAccount.java

  * @author leon on 27/12/2018.
  */
 public class BankAccount {
-    public void increaseBalance(Double amountToIncreaseBy) {
+    public void deposit(Double amountToIncreaseBy) {
 
     }
 
-    public void decreaseBalance(Double amountToIncreaseBy) {
+    public void withdrawal(Double amountToDecreaseBy) {
 
     }
 
     public Double getBalance() {
         return null;
     }
+
+    public void setBalance(Double val) {
+    }
 }

src/test/java/rocks/zipcode/quiz3a/objectorientation/bankaccount/DecreaseBalanceTest.java

-package rocks.zipcode.quiz3a.objectorientation.bankaccount;
-
-/**
- * @author leon on 30/12/2018.
- */
-public class DecreaseBalanceTest {
-}

src/test/java/rocks/zipcode/quiz3a/objectorientation/bankaccount/DepositTest.java

+package rocks.zipcode.quiz3a.objectorientation.bankaccount;
+
+import org.junit.Assert;
+import org.junit.Test;
+import rocks.zipcode.quiz3a.objectorientation.account.BankAccount;
+
+/**
+ * @author leon on 30/12/2018.
+ */
+public class DepositTest {
+    @Test
+    public void test1() {
+        test(100.0, 80.0);
+    }
+
+    @Test
+    public void test2() {
+        test(150.0, 70.0);
+    }
+
+    @Test
+    public void test3() {
+        test(100.0, 180.0);
+    }
+
+    @Test
+    public void test4() {
+        test(10.0, 50.0);
+    }
+
+    public void test(Double initialBalance, Double withdrawalAmount) {
+        // given
+        Double expected = initialBalance + withdrawalAmount;
+        BankAccount bankAccount = new BankAccount();
+        bankAccount.setBalance(initialBalance);
+
+        // when
+        bankAccount.withdrawal(withdrawalAmount);
+        Double actual = bankAccount.getBalance();
+
+        // then
+        Assert.assertEquals(expected, actual);
+    }
+}

src/test/java/rocks/zipcode/quiz3a/objectorientation/bankaccount/IncreaseBalanceTest.java

-package rocks.zipcode.quiz3a.objectorientation.bankaccount;
-
-/**
- * @author leon on 30/12/2018.
- */
-public class IncreaseBalanceTest {
-}

src/test/java/rocks/zipcode/quiz3a/objectorientation/bankaccount/WithdrawalTest.java

+package rocks.zipcode.quiz3a.objectorientation.bankaccount;
+
+import org.junit.Assert;
+import org.junit.Test;
+import rocks.zipcode.quiz3a.objectorientation.account.BankAccount;
+
+/**
+ * @author leon on 30/12/2018.
+ */
+public class WithdrawalTest {
+    @Test
+    public void test1() {
+        test(100.0, 80.0);
+    }
+
+    @Test
+    public void test2() {
+        test(150.0, 70.0);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void test3() {
+        test(100.0, 180.0);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void test4() {
+        test(10.0, 50.0);
+    }
+
+    public void test(Double initialBalance, Double withdrawalAmount) {
+        // given
+        Double expected = initialBalance - withdrawalAmount;
+        BankAccount bankAccount = new BankAccount();
+        bankAccount.setBalance(initialBalance);
+
+        // when
+        bankAccount.withdrawal(withdrawalAmount);
+        Double actual = bankAccount.getBalance();
+
+        // then
+        Assert.assertEquals(expected, actual);
+    }
+}

src/test/java/rocks/zipcode/quiz3a/objectorientation/employee/EmployeeConstructorTest.java

         Double expectedBankAccountBalance = expectedBalance;
         Double expectedMoneyEarned = expectedHourlyWage * expectedHoursWorked;
         BankAccount bankAccount = new BankAccount();
-        bankAccount.increaseBalance(expectedBankAccountBalance);
+        bankAccount.setBalance(expectedBankAccountBalance);
 
         // when
         Employee employee = new Employee(bankAccount);