tests warnings are fixed now and the git workflow is updated

Author: babisque

.github/workflows/dotnet.yml

@@ -26,3 +26,6 @@ jobs:
     - name: Build
       run: dotnet build --no-restore
       working-directory: ./Catalog/
+      - name: Test
+      run: dotnet test --no-build --verbosity normal
+      working-directory: ./Catalog/

Catalog/Catalog.Test/ProductControllerTests.cs

@@ -141,7 +141,7 @@ public async Task GetProduct_NonExistingId_ReturnsNotFound()
     {
         // Arrange
         _productRepositoryMock.Setup(repo => repo.GetByIdAsync(1))
-            .ReturnsAsync((Product)null);
+            .ReturnsAsync((Product)null!);
 
         // Act
         var result = await _controller.GetProduct(1);
@@ -196,7 +196,7 @@ public async Task Delete_NonExistingId_ReturnsNotFound()
     {
         // Arrange
         _productRepositoryMock.Setup(repo => repo.GetByIdAsync(1))
-            .ReturnsAsync((Product)null);
+            .ReturnsAsync((Product)null!);
 
         // Act
         var result = await _controller.Delete(1);