diff --git a/java/TODO.md b/java/TODO.md
index aec0c21..7ac3e18 100644
--- a/java/TODO.md
+++ b/java/TODO.md
@@ -4,7 +4,7 @@
 We will be using the mikado method to incrementally create the test data builder pattern for the Invoice class.
 Indentation represents dependencies, and should be done first
 
-- [ ] Add a test to highlight the issue in Invoice, using the test data builder pattern
+- [x] Add a test to highlight the issue in Invoice, using the test data builder pattern
   - [x] Create a test data builder for the Invoice class
     - [x] Create a test data builder for the PurchaseBook class
       - [x] Create a test data builder for the Novel class
diff --git a/java/src/test/java/com/murex/tbw/purchase/InvoiceTest.java b/java/src/test/java/com/murex/tbw/purchase/InvoiceTest.java
index 73ee0a9..0495399 100644
--- a/java/src/test/java/com/murex/tbw/purchase/InvoiceTest.java
+++ b/java/src/test/java/com/murex/tbw/purchase/InvoiceTest.java
@@ -1,9 +1,12 @@
 package com.murex.tbw.purchase;
 
+import com.murex.tbw.domain.country.TestCountries;
 import org.junit.jupiter.api.Test;
 
 import static com.murex.tbw.domain.book.NovelTestDataBuilder.aNovel;
+import static com.murex.tbw.purchase.InvoiceTestDataBuilder.anInvoice;
 import static com.murex.tbw.purchase.PurchasedBookTestDataBuilder.aPurchase;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 class InvoiceTest {
     @Test
@@ -32,17 +35,11 @@ void Mikado_Method_Constraint_Applies_tax_rules_when_computing_total_amount() {
     @Test
     void Mikado_Method_And_Test_Data_Builders_Constraint_Applies_tax_rules_when_computing_total_amount() {
         // Using the Mikado method and the Test Data Builder pattern:
-        // Instantiate an Invoice sent to USA
-//        InvoiceBuilder.anInvoice()
-//                .sentTo("USA")
-//                .withItem(aNovel()
-//                        .costing(50))
-//                .build();
-
-        aPurchase().of(aNovel().costing(50)).quantity(1).build();
 
+        Invoice invoice = anInvoice().sentTo(TestCountries.USA)
+                .with(aPurchase().of(aNovel().costing(50))).build();
 
-        // Add it a purchased novel costing 50
         // Assert the total amount of the invoice is 56,35 : 15% of taxes plus a 2% reduction on novels
+        assertEquals(56.35, invoice.computeTotalAmount());
     }
 }