Merge pull request #2 from WB3Tech-Java/add-money-comparators

Add money comparators

Author: WB3Tech

src/main/java/com/wb3tech/kernel/valueobject/Money.java

@@ -44,6 +44,21 @@ public Money Minus(Money money) {
         return new Money(totalAmount, this.currency);
     }
 
+    public boolean LessThan(Money money) {
+        this.validateDifferentCurrencyForAmountComparators(money);
+        return this.getAmount() < money.getAmount();
+    }
+
+    public boolean GreaterThan(Money money) {
+        this.validateDifferentCurrencyForAmountComparators(money);
+        return this.getAmount() > money.getAmount();
+    }
+
+    public boolean Equals(Money money) {
+        this.validateDifferentCurrencyForAmountComparators(money);
+        return this.getAmount() == money.getAmount();
+    }
+
     public double getAmount() {
         return this.amount.doubleValue();
     }
@@ -80,4 +95,8 @@ private boolean isDifferentCurrency(Money money) {
         return !this.isSameCurrency(money);
     }
 
+    private void validateDifferentCurrencyForAmountComparators(Money money) {
+        if(this.isDifferentCurrency(money)) { throw new ArithmeticException("Cannot compare of two different currencies."); }
+    }
+
 }

src/test/java/com/wb3tech/kernel/valueobject/MoneyTests.java

@@ -87,6 +87,39 @@ public void SubtractTwoMonies() {
 
     }
 
+    @Test @Tag("Small") @DisplayName("Money with amount of 13.00 USD should be less than Money with amount 15.00 USD")
+    public void CompareAmountLessThan() {
+
+        var thirteen = Money.Of(13.00, "USD");
+        var fifteen = Money.Of(15.00, "USD");
+        var isLessThan = thirteen.LessThan(fifteen);
+
+        assertTrue(isLessThan);
+
+    }
+
+    @Test @Tag("Small") @DisplayName("Money with amount of 15.00 USD should be greater than Money with amount 13.00 USD")
+    public void CompareAmountGreaterThan() {
+
+        var thirteen = Money.Of(13.00, "USD");
+        var fifteen = Money.Of(15.00, "USD");
+        var isGreaterThan = fifteen.GreaterThan(thirteen);
+
+        assertTrue(isGreaterThan);
+
+    }
+
+    @Test @Tag("Small") @DisplayName("Money with amount of 13.00 USD should equal money with amount 13.00 USD")
+    public void CompareAmountEquals() {
+
+        var fifteenInstanceOne = Money.Of(15.00, "USD");
+        var fifteenInstanceTwo = Money.Of(15.00, "USD");
+        var isGreaterThan = fifteenInstanceOne.Equals(fifteenInstanceTwo);
+
+        assertTrue(isGreaterThan);
+
+    }
+
     @Test @Tag("Small") @DisplayName("Should get a Money with amount of -5 when you subtract a money instance of 10 " +
             "and a second instance o 15")
     public void ShouldGetNegativeMoney() {
@@ -99,7 +132,7 @@ public void ShouldGetNegativeMoney() {
 
     }
 
-    @Test @Tag("Small") @DisplayName("Should throw an ArithmeticExceptionn" +
+    @Test @Tag("Small") @DisplayName("Should throw an ArithmeticException" +
             "with message 'Cannot subtract monies of two different currencies'")
     public void SubtractShouldThrowArithmeticExceptionForNotSameCurrency() {
 
@@ -125,6 +158,45 @@ public void AddShouldThrowArithmeticExceptionForNotSameCurrency() {
 
     }
 
+    @Test @Tag("Small") @DisplayName("Should throw an ArithmeticException " +
+            "with message 'Cannot compare of two different currencies.' " +
+            "when comparing amount-less-than for two different currencies.")
+    public void AmountLessThanThrowArithmeticExceptionForNotSameCurrency() {
+
+        var thirteen = Money.Of(13.00, "USD");
+        var fifteen = Money.Of(15.00, "GBP");
+
+        var exception = assertThrows(ArithmeticException.class, () -> thirteen.LessThan(fifteen));
+        Assertions.assertEquals("Cannot compare of two different currencies.", exception.getMessage());
+
+    }
+
+    @Test @Tag("Small") @DisplayName("Should throw an ArithmeticException " +
+            "with message 'Cannot compare of two different currencies.' " +
+            "when comparing amount-greater-than for two different currencies.")
+    public void AmountGreaterThanArithmeticExceptionForNotSameCurrency() {
+
+        var thirteen = Money.Of(13.00, "USD");
+        var fifteen = Money.Of(15.00, "GBP");
+
+        var exception = assertThrows(ArithmeticException.class, () -> fifteen.GreaterThan(thirteen));
+        Assertions.assertEquals("Cannot compare of two different currencies.", exception.getMessage());
+
+    }
+
+    @Test @Tag("Small") @DisplayName("Should throw an ArithmeticException " +
+            "with message 'Cannot compare of two different currencies.' " +
+            "when comparing amount-equals for two different currencies.")
+    public void AmountEqualsArithmeticExceptionForNotSameCurrency() {
+
+        var fifteenInstanceOne = Money.Of(15.00, "USD");
+        var fifteenInstanceTwo = Money.Of(15.00, "GBP");
+
+        var exception = assertThrows(ArithmeticException.class, () -> fifteenInstanceOne.Equals(fifteenInstanceTwo));
+        Assertions.assertEquals("Cannot compare of two different currencies.", exception.getMessage());
+
+    }
+
     @Test @Tag("Small") @DisplayName("A money instance of $1 should equal the second instance of $1")
     public void ShouldEqual() {