TestDataBuilders: ValidOrder()/ValidClient() with explicit Build(); After tests migrated

Domain objects in After-side tests are constructed only through the
builders, so the upcoming OrderLines evolution changes builder internals
instead of every test. Before keeps object initializers (legacy world).

yak: testdatabuilders-validordervalidclient-after-test-migration-91vl

tests/BeforeAfter.Tests/DiscountCalculatorTests.cs

@@ -1,4 +1,6 @@
 using After;
+using static BeforeAfter.Tests.TestData.ClientBuilder;
+using static BeforeAfter.Tests.TestData.OrderBuilder;
 
 namespace BeforeAfter.Tests;
 
@@ -16,7 +18,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void A_total_below_the_barrier_gets_no_discount()
     {
-        var order = new Order { Id = Guid.NewGuid(), Description = "small", TotalInCents = 50_00 };
+        var order = ValidOrder().WithTotal(50_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 10);
 
@@ -28,7 +30,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void A_total_exactly_at_the_barrier_gets_no_discount()
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = 100_00 };
+        var order = ValidOrder().WithTotal(100_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 10);
 
@@ -42,7 +44,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void A_total_above_the_barrier_gets_the_percentage_discount()
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = 150_00 };
+        var order = ValidOrder().WithTotal(150_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 10);
 
@@ -54,7 +56,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void A_zero_percentage_discounts_nothing_even_above_the_barrier()
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = 150_00 };
+        var order = ValidOrder().WithTotal(150_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 0);
 
@@ -65,7 +67,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void A_hundred_percent_discount_leaves_nothing()
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = 150_00 };
+        var order = ValidOrder().WithTotal(150_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 100);
 
@@ -83,7 +85,7 @@ public class DiscountCalculatorTests
     [InlineData(151, 15, 136)]   // 15.1 rounds down to 15
     public void The_discount_amount_is_rounded_half_up(int totalInCents, int expectedDiscountCents, int expectedDiscountedTotal)
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = totalInCents };
+        var order = ValidOrder().WithTotal(totalInCents).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100, discountPercentage: 10);
 
@@ -98,7 +100,7 @@ public class DiscountCalculatorTests
     public void The_result_is_correlated_to_the_order_by_id()
     {
         var id = Guid.NewGuid();
-        var order = new Order { Id = id, TotalInCents = 150_00 };
+        var order = ValidOrder().WithId(id).WithTotal(150_00).Build();
 
         var discounted = DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 10);
 
@@ -108,7 +110,7 @@ public class DiscountCalculatorTests
     [Fact]
     public void Calculating_does_not_mutate_the_order()
     {
-        var order = new Order { Id = Guid.NewGuid(), Description = "one", TotalInCents = 150_00 };
+        var order = ValidOrder().WithDescription("one").WithTotal(150_00).Build();
 
         DiscountCalculator.CalculateDiscount(order, discountBarrierCents: 100_00, discountPercentage: 10);
 
@@ -120,13 +122,13 @@ public class DiscountCalculatorTests
     // Input validation: invalid arguments throw (loudly, not silently).
     // ---------------------------------------------------------------------
     [Theory]
-    [InlineData(-1, 100_00, 10)]    // negative total
-    [InlineData(150_00, -1, 10)]    // negative barrier
-    [InlineData(150_00, 100_00, -1)]// percentage below 0
+    [InlineData(-1, 100_00, 10)]     // negative total
+    [InlineData(150_00, -1, 10)]     // negative barrier
+    [InlineData(150_00, 100_00, -1)] // percentage below 0
     [InlineData(150_00, 100_00, 101)]// percentage above 100
     public void Invalid_arguments_throw(int totalInCents, int discountBarrierCents, int discountPercentage)
     {
-        var order = new Order { Id = Guid.NewGuid(), TotalInCents = totalInCents };
+        var order = ValidOrder().WithTotal(totalInCents).Build();
 
         Assert.Throws<ArgumentOutOfRangeException>(
             () => DiscountCalculator.CalculateDiscount(order, discountBarrierCents, discountPercentage));