read only and tests

CoreUnitTests/Infrastructure/Model/TestDocument.cs

@@ -4,23 +4,21 @@ using MongoDbGenericRepository.Models;
 
 namespace CoreUnitTests.Infrastructure.Model;
 
-
 public class TestDocument : Document
 {
     public TestDocument()
     {
         Version = 2;
-        Nested = new Nested
-        {
-            SomeDate = DateTime.UtcNow
-        };
+        Nested = new Nested {SomeDate = DateTime.UtcNow};
         Children = new List<Child>();
     }
 
     public int SomeValue { get; set; }
 
     public string SomeContent { get; set; }
+
     public string SomeContent2 { get; set; }
+
     public string SomeContent3 { get; set; }
 
     public int GroupingKey { get; set; }
@@ -29,4 +27,3 @@ public class TestDocument : Document
 
     public List<Child> Children { get; set; }
 }
-

CoreUnitTests/Infrastructure/Model/TestProjection.cs

@@ -7,4 +7,6 @@ public class TestProjection
     public Guid TestDocumentId { get; set; }
 
     public DateTime NestedData { get; set; }
+
+    public int Count { get; set; }
 }

CoreUnitTests/Infrastructure/TestKeyedMongoRepository.cs

@@ -16,23 +16,11 @@ public class TestKeyedMongoRepository<TKey> : BaseMongoRepository<TKey>
     {
     }
 
-    public void SetIndexHandler(IMongoDbIndexHandler indexHandler)
-    {
-        MongoDbIndexHandler = indexHandler;
-    }
+    public void SetIndexHandler(IMongoDbIndexHandler indexHandler) => MongoDbIndexHandler = indexHandler;
 
-    public void SetDbCreator(IMongoDbCreator creator)
-    {
-        MongoDbCreator = creator;
-    }
+    public void SetDbCreator(IMongoDbCreator creator) => MongoDbCreator = creator;
 
-    public void SetReader(IMongoDbReader reader)
-    {
-        MongoDbReader = reader;
-    }
+    public void SetReader(IMongoDbReader reader) => MongoDbReader = reader;
 
-    public void SetEraser(IMongoDbEraser eraser)
-    {
-        MongoDbEraser = eraser;
-    }
+    public void SetEraser(IMongoDbEraser eraser) => MongoDbEraser = eraser;
 }

CoreUnitTests/Infrastructure/TestKeyedMongoRepositoryContext.cs

@@ -12,13 +12,13 @@ namespace CoreUnitTests.Infrastructure;
 public class TestKeyedMongoRepositoryContext<TKey>
     where TKey : IEquatable<TKey>
 {
-    private readonly Mock<IMongoDatabase> _mongoDatabase;
+    private readonly Mock<IMongoDatabase> mongoDatabase;
 
-    private TestKeyedMongoRepository<TKey> _sut;
+    private TestKeyedMongoRepository<TKey> sut;
 
     protected TestKeyedMongoRepositoryContext()
     {
-        _mongoDatabase = new Mock<IMongoDatabase>();
+        mongoDatabase = new Mock<IMongoDatabase>();
         Fixture = new Fixture();
     }
 
@@ -28,33 +28,33 @@ public class TestKeyedMongoRepositoryContext<TKey>
     {
         get
         {
-            if (_sut != null)
+            if (sut != null)
             {
-                return _sut;
+                return sut;
             }
 
-            _sut = new TestKeyedMongoRepository<TKey>(_mongoDatabase.Object);
+            sut = new TestKeyedMongoRepository<TKey>(mongoDatabase.Object);
             if (IndexHandler != null)
             {
-                _sut.SetIndexHandler(IndexHandler.Object);
+                sut.SetIndexHandler(IndexHandler.Object);
             }
 
             if (Creator != null)
             {
-                _sut.SetDbCreator(Creator.Object);
+                sut.SetDbCreator(Creator.Object);
             }
 
             if (Reader != null)
             {
-                _sut.SetReader(Reader.Object);
+                sut.SetReader(Reader.Object);
             }
 
             if (Eraser != null)
             {
-                _sut.SetEraser(Eraser.Object);
+                sut.SetEraser(Eraser.Object);
             }
 
-            return _sut;
+            return sut;
         }
     }
 

CoreUnitTests/Infrastructure/TestKeyedReadOnlyMongoRepository.cs

@@ -0,0 +1,30 @@
+using System;
+using MongoDB.Driver;
+using MongoDbGenericRepository;
+using MongoDbGenericRepository.DataAccess.Read;
+
+namespace CoreUnitTests.Infrastructure;
+
+public class TestKeyedReadOnlyMongoRepository<TKey> : ReadOnlyMongoRepository<TKey>
+    where TKey : IEquatable<TKey>
+{
+    /// <inheritdoc />
+    public TestKeyedReadOnlyMongoRepository(string connectionString, string databaseName = null)
+        : base(connectionString, databaseName)
+    {
+    }
+
+    /// <inheritdoc />
+    public TestKeyedReadOnlyMongoRepository(IMongoDatabase mongoDatabase)
+        : base(mongoDatabase)
+    {
+    }
+
+    /// <inheritdoc />
+    public TestKeyedReadOnlyMongoRepository(IMongoDbContext mongoDbContext)
+        : base(mongoDbContext)
+    {
+    }
+
+    public void SetReader(IMongoDbReader reader) => MongoDbReader = reader;
+}

CoreUnitTests/Infrastructure/TestKeyedReadOnlyMongoRepositoryContext.cs

@@ -0,0 +1,45 @@
+using System;
+using AutoFixture;
+using MongoDB.Driver;
+using MongoDbGenericRepository.DataAccess.Read;
+using Moq;
+
+namespace CoreUnitTests.Infrastructure;
+
+public class TestKeyedReadOnlyMongoRepositoryContext<TKey>
+    where TKey : IEquatable<TKey>
+{
+    private readonly Mock<IMongoDatabase> mongoDatabase;
+
+    private TestKeyedReadOnlyMongoRepository<TKey> sut;
+
+    protected TestKeyedReadOnlyMongoRepositoryContext()
+    {
+        mongoDatabase = new Mock<IMongoDatabase>();
+        Fixture = new Fixture();
+    }
+
+    protected Fixture Fixture { get; set; }
+
+    protected TestKeyedReadOnlyMongoRepository<TKey> Sut
+    {
+        get
+        {
+            if (sut != null)
+            {
+                return sut;
+            }
+
+            sut = new TestKeyedReadOnlyMongoRepository<TKey>(mongoDatabase.Object);
+
+            if (Reader != null)
+            {
+                sut.SetReader(Reader.Object);
+            }
+
+            return sut;
+        }
+    }
+
+    protected Mock<IMongoDbReader> Reader { get; set; }
+}

CoreUnitTests/ReadOnlyMongoRepositoryTests/GetSortedPaginatedAsyncTests.cs

@@ -0,0 +1,246 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Threading;
+using System.Threading.Tasks;
+using AutoFixture;
+using CoreUnitTests.Infrastructure;
+using CoreUnitTests.Infrastructure.Model;
+using FluentAssertions;
+using MongoDB.Driver;
+using MongoDbGenericRepository.DataAccess.Read;
+using Moq;
+using Xunit;
+
+namespace CoreUnitTests.ReadOnlyMongoRepositoryTests;
+
+public class GetSortedPaginatedAsyncTests : TestKeyedReadOnlyMongoRepositoryContext<Guid>
+{
+    private readonly Expression<Func<TestDocument, bool>> filter = document => document.GroupingKey == 1;
+    private readonly Expression<Func<TestDocument, object>> selector = document => document.GroupingKey;
+    private readonly SortDefinition<TestDocument> sortDefinition = Builders<TestDocument>.Sort.Ascending(document => document.GroupingKey);
+
+    private const bool DefaultAscending = true;
+    private const int DefaultSkipNumber = 0;
+    private const int DefaultTakeNumber = 50;
+
+    [Fact]
+    public async Task WithFilterAndSortSelector_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector);
+
+        // Assert
+        VerifySelector(result, documents, DefaultAscending, DefaultSkipNumber, DefaultTakeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortSelectorAndAscending_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+        var ascending = Fixture.Create<bool>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector, ascending);
+
+        // Assert
+        VerifySelector(result, documents, ascending, DefaultSkipNumber, DefaultTakeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortSelectorAndSkipNumber_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+        var skipNumber = Fixture.Create<int>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector, skipNumber: skipNumber);
+
+        // Assert
+        VerifySelector(result, documents, DefaultAscending, skipNumber, DefaultTakeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortSelectorAndTakeNumber_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+        var ascending = Fixture.Create<bool>();
+        var takeNumber = Fixture.Create<int>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector, ascending, takeNumber: takeNumber);
+
+        // Assert
+        VerifySelector(result, documents, ascending, DefaultSkipNumber, takeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortSelectorAndPartitionKey_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+        var partitionKey = Fixture.Create<string>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector, partitionKey: partitionKey);
+
+        // Assert
+        VerifySelector(result, documents, DefaultAscending, DefaultSkipNumber, DefaultTakeNumber, partitionKey, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortSelectorAndCancellationToken_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortSelector();
+        var cancellationToken = new CancellationToken(true);
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, selector, cancellationToken: cancellationToken);
+
+        // Assert
+        VerifySelector(result, documents, DefaultAscending, DefaultSkipNumber, DefaultTakeNumber, null, cancellationToken);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortDefinition_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortDefinition();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, sortDefinition);
+
+        // Assert
+        VerifyDefinition(result, documents, DefaultSkipNumber, DefaultTakeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortDefinitionAndSkipNumber_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortDefinition();
+        var skipNumber = Fixture.Create<int>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, sortDefinition, skipNumber);
+
+        // Assert
+        VerifyDefinition(result, documents, skipNumber, DefaultTakeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortDefinitionAndTakeNumber_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortDefinition();
+        var takeNumber = Fixture.Create<int>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, sortDefinition, takeNumber: takeNumber);
+
+        // Assert
+        VerifyDefinition(result, documents, DefaultSkipNumber, takeNumber, null, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortDefinitionAndPartitionKey_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortDefinition();
+        var partitionKey = Fixture.Create<string>();
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, sortDefinition, partitionKey: partitionKey);
+
+        // Assert
+        VerifyDefinition(result, documents, DefaultSkipNumber, DefaultTakeNumber, partitionKey, CancellationToken.None);
+    }
+
+    [Fact]
+    public async Task WithFilterAndSortDefinitionAndCancellationToken_GetsResults()
+    {
+        // Arrange
+        var documents = SetupReaderWithSortDefinition();
+        var token = new CancellationToken(true);
+
+        // Act
+        var result = await Sut.GetSortedPaginatedAsync(filter, sortDefinition, cancellationToken: token);
+
+        // Assert
+        VerifyDefinition(result, documents, DefaultSkipNumber, DefaultTakeNumber, null, token);
+    }
+
+    private List<TestDocument> SetupReaderWithSortSelector()
+    {
+        var documents = Fixture.CreateMany<TestDocument>().ToList();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GetSortedPaginatedAsync<TestDocument, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, bool>>>(),
+                    It.IsAny<Expression<Func<TestDocument, object>>>(),
+                    It.IsAny<bool>(),
+                    It.IsAny<int>(),
+                    It.IsAny<int>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .ReturnsAsync(documents);
+        return documents;
+    }
+
+    private void VerifySelector(List<TestDocument> result, List<TestDocument> documents, bool ascending, int skipNumber, int takeNumber, string partitionKey, CancellationToken cancellationToken)
+    {
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(documents);
+        Reader.Verify(
+            x => x.GetSortedPaginatedAsync<TestDocument, Guid>(
+                filter,
+                selector,
+                ascending,
+                skipNumber,
+                takeNumber,
+                partitionKey,
+                cancellationToken),
+            Times.Once);
+    }
+
+    private List<TestDocument> SetupReaderWithSortDefinition()
+    {
+        var documents = Fixture.CreateMany<TestDocument>().ToList();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GetSortedPaginatedAsync<TestDocument, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, bool>>>(),
+                    It.IsAny<SortDefinition<TestDocument>>(),
+                    It.IsAny<int>(),
+                    It.IsAny<int>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .ReturnsAsync(documents);
+        return documents;
+    }
+
+    private void VerifyDefinition(List<TestDocument> result, List<TestDocument> documents, int skipNumber, int takeNumber, string partitionKey, CancellationToken cancellationToken)
+    {
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(documents);
+        Reader.Verify(
+            x => x.GetSortedPaginatedAsync<TestDocument, Guid>(
+                filter,
+                sortDefinition,
+                skipNumber,
+                takeNumber,
+                partitionKey,
+                cancellationToken),
+            Times.Once);
+    }
+}

CoreUnitTests/ReadOnlyMongoRepositoryTests/GroupByTests.cs

@@ -0,0 +1,243 @@
+using System;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Threading;
+using AutoFixture;
+using CoreUnitTests.Infrastructure;
+using CoreUnitTests.Infrastructure.Model;
+using FluentAssertions;
+using MongoDbGenericRepository.DataAccess.Read;
+using Moq;
+using Xunit;
+
+namespace CoreUnitTests.ReadOnlyMongoRepositoryTests;
+
+public class GroupByTests : TestKeyedReadOnlyMongoRepositoryContext<Guid>
+{
+    private readonly Expression<Func<TestDocument, int>> grouping = document => document.GroupingKey;
+    private readonly Expression<Func<IGrouping<int, TestDocument>, TestProjection>> projection = documents => new TestProjection {Count = documents.Count()};
+    private readonly Expression<Func<TestDocument, bool>> filter = document => document.GroupingKey == 1;
+
+    [Fact]
+    public void WithGroupingCriteriaAndProjection_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(grouping, projection);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(grouping, projection, null, CancellationToken.None),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithGroupingCriteriaAndProjectionAndCancellationToken_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var token = new CancellationToken(true);
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader
+            .Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(grouping, projection, token);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(grouping, projection, null, token),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithGroupingCriteriaAndProjectionAndPartitionKey_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var partitionKey = Fixture.Create<string>();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader
+            .Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(grouping, projection, partitionKey);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(grouping, projection, partitionKey, CancellationToken.None),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithGroupingCriteriaAndProjectionAndPartitionKeyAndCancellationToken_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var partitionKey = Fixture.Create<string>();
+        var token = new CancellationToken(true);
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader
+            .Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(grouping, projection, partitionKey, token);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(grouping, projection, partitionKey, token),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithFilterAndGroupingCriteriaAndProjection_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument,bool>>>(),
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(filter, grouping, projection);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(filter, grouping, projection, null, CancellationToken.None),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithFilterAndGroupingCriteriaAndProjectionAndCancellationToken_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var token = new CancellationToken(true);
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument,bool>>>(),
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(filter, grouping, projection, token);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(filter, grouping, projection, null, token),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithFilterAndGroupingCriteriaAndProjectionAndPartitionKey_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var partitionKey = Fixture.Create<string>();
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument,bool>>>(),
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(filter, grouping, projection, partitionKey);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(filter, grouping, projection, partitionKey, CancellationToken.None),
+            Times.Once);
+    }
+
+    [Fact]
+    public void WithFilterAndGroupingCriteriaAndProjectionAndPartitionKeyAndCancellationToken_Groups()
+    {
+        // Arrange
+        var projections = Fixture.CreateMany<TestProjection>().ToList();
+        var partitionKey = Fixture.Create<string>();
+        var token = new CancellationToken(true);
+        Reader = new Mock<IMongoDbReader>();
+
+        Reader.Setup(
+                x => x.GroupBy<TestDocument, int, TestProjection, Guid>(
+                    It.IsAny<Expression<Func<TestDocument,bool>>>(),
+                    It.IsAny<Expression<Func<TestDocument, int>>>(),
+                    It.IsAny<Expression<Func<IGrouping<int, TestDocument>, TestProjection>>>(),
+                    It.IsAny<string>(),
+                    It.IsAny<CancellationToken>()))
+            .Returns(projections);
+
+        // Act
+        var result = Sut.GroupBy(filter, grouping, projection, partitionKey, token);
+
+        // Assert
+        result.Should().NotBeNull();
+        result.Should().BeEquivalentTo(projections);
+        Reader.Verify(
+            x => x.GroupBy<TestDocument, int, TestProjection, Guid>(filter, grouping, projection, partitionKey, token),
+            Times.Once);
+    }
+}