Add initial implementation of product management API

EndavaTask.Tests/InMemoryProductRepositoryTests.cs

@@ -0,0 +1,44 @@
+using EndavaTask.Contracts;
+using EndavaTask.Data;
+using Xunit;
+
+namespace EndavaTask.Tests;
+
+public class InMemoryProductRepositoryTests
+{
+    private readonly InMemoryProductRepository _repository = new();
+
+    [Fact]
+    public void GetFilteredProducts_FiltersByNameCategoryAndPriceRange_WithPagination()
+    {
+        var filter = new ProductFilterQuery
+        {
+            Name = "mon",
+            CategoryId = Guid.Parse("aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"),
+            MinPrice = 200m,
+            MaxPrice = 350m
+        };
+
+        var result = _repository.GetFilteredProducts(filter, new PaginationQuery { PageNumber = 1, PageSize = 10 });
+
+        Assert.Single(result.Items);
+        
+        var product = Assert.Single(result.Items);
+        
+        Assert.Equal("Monitor", product.Name);
+        Assert.Equal(1, result.TotalCount);
+        Assert.Equal(1, result.TotalPages);
+    }
+
+    [Fact]
+    public void GetFilteredProducts_ReturnsPagedData_WhenNoFilters()
+    {
+        var result = _repository.GetFilteredProducts(new ProductFilterQuery(), new PaginationQuery { PageNumber = 2, PageSize = 2 });
+
+        Assert.Equal(2, result.Items.Count);
+        Assert.Equal(5, result.TotalCount);
+        Assert.Equal(3, result.TotalPages);
+        Assert.Equal(2, result.PageNumber);
+        Assert.Equal(2, result.PageSize);
+    }
+}