From a672685c9be7c78c5d556525bb1ba95adc407c07 Mon Sep 17 00:00:00 2001
From: Ivan Ivon <ivan.ivon@zerto.com>
Date: Mon, 8 Mar 2021 01:17:02 +0200
Subject: [PATCH] Add single class generation for the similar CSV files.

---
 README.md                                     |  9 ++--
 .../CodeGen/CsvCSharpCodeGenerator.cs         | 52 +++++++++++++------
 Src/CsvLINQPadDriver/ConnectionDialog.xaml    | 19 +++----
 .../CsvDataContextDriverProperties.cs         |  6 +++
 Src/CsvLINQPadDriver/CsvLINQPadDriver.csproj  |  2 +-
 .../DataModel/CsvDataModelGenerator.cs        | 50 ++++++++++++------
 Src/CsvLINQPadDriver/DataModel/CsvTable.cs    |  8 +++
 Src/CsvLINQPadDriver/Helpers/FileUtils.cs     |  4 +-
 .../ICsvDataContextDriverProperties.cs        |  7 ++-
 Src/CsvLINQPadDriver/SchemaBuilder.cs         | 37 ++++++++++---
 .../CsvLINQPadDriverTest/SchemaBuilderTest.cs | 13 +++--
 11 files changed, 146 insertions(+), 61 deletions(-)

diff --git a/README.md b/README.md
index 54c8806..f839823 100644
--- a/README.md
+++ b/README.md
@@ -7,10 +7,10 @@ CsvLINQPadDriver For LINQPad 6
 
 CsvLINQPadDriver is LINQPad 6 data context dynamic driver for querying CSV files.
 
-You can query data in CSV files with LINQ, just like it would be regular database. No need to write custom data model, mappings etc.
-
-Driver automatically generates new data types for every CSV file with corresponding properties and mappings for all columns.
-Based on column and file names, possible relations between CSV tables are detected and generated.
+- You can query data in CSV files with LINQ, just like it would be regular database. No need to write custom data model, mappings, etc.
+- Driver automatically generates new data types for every CSV file with corresponding properties and mappings for all columns.
+- Based on column and file names, possible relations between CSV tables are detected and generated.
+- Single class generation allows to join similar files and query over them. Might not work well for files with relations.
 
 Website
 --
@@ -154,6 +154,7 @@ Known Issues
 --
 - Some strange Unicode characters in column names may cause errors in generated data context source code.
 - Writing changed objects back to CSV is not directly supported, there is no `.SubmitChanges()` . But you can use LINQPad's `Util.WriteCsv`.
+- Similar files single class generation might not work well for files with relations.
 
 Author
 --
diff --git a/Src/CsvLINQPadDriver/CodeGen/CsvCSharpCodeGenerator.cs b/Src/CsvLINQPadDriver/CodeGen/CsvCSharpCodeGenerator.cs
index a89a210..df80827 100644
--- a/Src/CsvLINQPadDriver/CodeGen/CsvCSharpCodeGenerator.cs
+++ b/Src/CsvLINQPadDriver/CodeGen/CsvCSharpCodeGenerator.cs
@@ -1,5 +1,6 @@
 using System;
 using System.CodeDom;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Security;
@@ -29,11 +30,21 @@ private CsvCSharpCodeGenerator(string contextNameSpace, string contextTypeName,
         }
 
         // ReSharper disable once RedundantAssignment
-        public static string GenerateCode(CsvDatabase db, ref string nameSpace, ref string typeName, ICsvDataContextDriverProperties props) =>
+        public static (string Code, IReadOnlyCollection<IGrouping<string, (string Type, string Code, string CodeName)>> CodeGroups)
+            GenerateCode(CsvDatabase db, ref string nameSpace, ref string typeName, ICsvDataContextDriverProperties props) =>
             new CsvCSharpCodeGenerator(nameSpace, typeName = DefaultContextTypeName, props).GenerateSrcFile(db);
 
-        private string GenerateSrcFile(CsvDatabase csvDatabase) =>
-                $@"using System;
+        private (string, IReadOnlyCollection<IGrouping<string, (string Type, string Code, string CodeName)>>) GenerateSrcFile(CsvDatabase csvDatabase)
+        {
+            var (_, csvTables) = csvDatabase;
+
+            var groups = csvTables
+                    .Select(table => GenerateTableRowDataTypeClass(table, _properties.HideRelationsFromDump))
+                    .GroupBy(typeCode => typeCode.Type)
+                    .ToList();
+
+            return ($@"
+using System;
 using System.Linq;
 using System.Collections.Generic;
 
@@ -41,17 +52,17 @@ namespace {_contextNameSpace}
 {{
     /// <summary>CSV Data Context</summary>
     public class {_contextTypeName} : {typeof(CsvDataContextBase).GetCodeTypeClassName()}
-    {{ {string.Join(string.Empty, csvDatabase.Tables.Select(table => $@"
+    {{ {string.Join(string.Empty, csvTables.Select(table => $@"
         /// <summary>File: {SecurityElement.Escape(table.FilePath)}</summary>
         public {typeof(CsvTableBase<>).GetCodeTypeClassName(table.GetCodeRowClassName())} {table.CodeName} {{ get; private set; }}")
                 )}
 
         public {_contextTypeName}()
         {{
-            //Init tables data {string.Join(string.Empty, csvDatabase.Tables.Select(table => $@"
+            //Init tables data {string.Join(string.Empty, csvTables.Select(table => $@"
             this.{table.CodeName} = {typeof(CsvTableFactory).GetCodeTypeClassName()}.CreateTable<{table.GetCodeRowClassName()}>(
-                {(_properties.IsStringInternEnabled ? "true" : "false")},
-                {(_properties.IsCacheEnabled ? "true" : "false")},
+                {GetBoolConst(_properties.IsStringInternEnabled)},
+                {GetBoolConst(_properties.IsCacheEnabled)},
                 {table.CsvSeparator.AsValidCSharpCode()},
                 {table.FilePath.AsValidCSharpCode()},
                 new {typeof(CsvColumnInfoList<>).GetCodeTypeClassName(table.GetCodeRowClassName())}() {{
@@ -66,12 +77,16 @@ public class {_contextTypeName} : {typeof(CsvDataContextBase).GetCodeTypeClassNa
         }}
     }}//context class
 
-    //Data types {string.Join(string.Empty, csvDatabase.Tables.Select(table => GenerateTableRowDataTypeClass(table, _properties.HideRelationsFromDump)))}
+    //Data types {string.Join(string.Empty, groups.Select(grouping => grouping.First().Code))}
 }}//namespace
-";
+", groups);
 
-        private static string GenerateTableRowDataTypeClass(CsvTable table, bool hideRelationsFromDump) =>
-            $@"
+            static string GetBoolConst(bool val) =>
+                val ? "true" : "false";
+        }
+
+        private static (string Type, string Code, string CodeName) GenerateTableRowDataTypeClass(CsvTable table, bool hideRelationsFromDump) =>
+            (table.GetCodeRowClassName(), $@"
     public class {table.GetCodeRowClassName()} : {typeof(ICsvRowBase).GetCodeTypeClassName()}
     {{{string.Join(string.Empty, table.Columns.Select(c => $@"
         public string {c.CodeName} {{ get; set; }} ")
@@ -80,16 +95,23 @@ public class {table.GetCodeRowClassName()} : {typeof(ICsvRowBase).GetCodeTypeCla
         [{typeof(HideFromDumpAttribute).GetCodeTypeClassName()}]" : string.Empty)}
         public IEnumerable<{csvRelation.TargetTable.GetCodeRowClassName()}> {csvRelation.CodeName} {{ get; set; }} ")
             )}
-    }} ";
+    }} ", table.CodeName!);
     }
 
     internal static class CsvCSharpCodeGeneratorExtensions
     {
-        public static string GetCodeRowClassName(this CsvTable table) =>
-            $"T{table.CodeName}";
+        public static string GetCodeRowClassName(this CsvTable table)
+        {
+            return ToClassName(table.ClassName);
+
+            static string ToClassName(string? name) =>
+                string.IsNullOrEmpty(name)
+                    ? throw new ArgumentNullException(nameof(name), "Name is null or empty")
+                    : $"T{name}";
+        }
 
         public static string GetCodeTypeClassName(this Type type, params string[] genericParameters) =>
-            type!.FullName!.Split('`')[0] + (genericParameters.Any() ? $"<{string.Join(",", genericParameters)}>" : string.Empty);
+            type.FullName!.Split('`').First() + (genericParameters.Any() ? $"<{string.Join(",", genericParameters)}>" : string.Empty);
 
         public static string AsValidCSharpCode<T>(this T input)
         {
diff --git a/Src/CsvLINQPadDriver/ConnectionDialog.xaml b/Src/CsvLINQPadDriver/ConnectionDialog.xaml
index df265fb..6ea0c73 100644
--- a/Src/CsvLINQPadDriver/ConnectionDialog.xaml
+++ b/Src/CsvLINQPadDriver/ConnectionDialog.xaml
@@ -35,7 +35,7 @@
             HorizontalScrollBarVisibility="Auto"
             VerticalScrollBarVisibility="Auto"
             Text="{Binding Files, UpdateSourceTrigger=PropertyChanged}" 
-            ToolTip="CSV files. Drag&amp;drop (use Ctrl to add files) or type one file per line. Supports mask '*.csv' or recursive '**.csv'."
+            ToolTip="CSV files. Drag&amp;drop (use Ctrl to add files) or type one file per line. Supports mask '*.csv' or recursive '**.csv'"
             AllowDrop="True"
             PreviewDragEnter="FilesTextBox_DragEnter"
             PreviewDragOver="FilesTextBox_DragEnter"
@@ -48,23 +48,24 @@
             <StackPanel Margin="2" Height="Auto">
                 <DockPanel>
                     <Label Padding="0,0,0,3" Content="CSV separator (autodetect if empty) "/>
-                    <TextBox MaxLength="6" MaxLines="1" Text="{Binding CsvSeparator}" ToolTip="Character used to separate columns in csv file. If empty, separator is auto-detected for each file."/>
+                    <TextBox MaxLength="6" MaxLines="1" Text="{Binding CsvSeparator}" ToolTip="Character used to separate columns in CSV file. If empty, separator is auto-detected for each file"/>
                 </DockPanel>
-                <CheckBox IsChecked="{Binding IgnoreInvalidFiles}" ToolTip="If checked, files with suspicious format will be ignored. (Only one column, variable count of columns in rows...)">Ignore files with invalid format</CheckBox>
+                <CheckBox IsChecked="{Binding IgnoreInvalidFiles}" ToolTip="Ignore files with invalid format">Ignore files with invalid format</CheckBox>
             </StackPanel>
             </GroupBox>
 
             <GroupBox Header="Memory">
                 <StackPanel Margin="2" Height="Auto">
-                    <CheckBox IsChecked="{Binding IsCacheEnabled}" ToolTip="If checked - Parsed rows from file are cached. This cache survives multiple query runs, even when query is changed. Cache is cleared as soon as LINQPad clears Application Domain of query. If unchecked - disable cache. Multiple enumerations of file content results in multiple reads and parsing of file. Can be significantly slower for complex queries. Significantly reduces memory usage. Useful when reading very large files.">Cache CSV data in memory</CheckBox>
-                    <CheckBox IsChecked="{Binding IsStringInternEnabled}" ToolTip="If checked, all string values are interned. Can significantly reduce memory consumption, when values in CSV are repeated many times.">String interning</CheckBox>
+                    <CheckBox IsChecked="{Binding IsCacheEnabled}" ToolTip="Cache parsed rows. This cache survives multiple query runs, even when query is changed">Cache CSV data in memory</CheckBox>
+                    <CheckBox IsChecked="{Binding IsStringInternEnabled}" ToolTip="Intern strings. Significantly reduce memory consumption when CSV contains repeatable values">Intern CSV strings</CheckBox>
                 </StackPanel>
             </GroupBox>
-            <CheckBox IsChecked="{Binding DetectRelations}" ToolTip="If checked, relations between csv files/tables will be detected and created. (Based on files and column names.)">Detect relations</CheckBox>
-            <CheckBox IsChecked="{Binding HideRelationsFromDump}"  IsEnabled="{Binding DetectRelations}" ToolTip="If checked - LINQPad will not show relations content in .Dump(). This prevents loading too many data." Margin="16,0,0,0">Hide relations from .Dump()</CheckBox>
-            <CheckBox IsChecked="{Binding DebugInfo}" ToolTip="Show/hide additional driver debug info.">Debug info</CheckBox>
+            <CheckBox IsChecked="{Binding UseSingleClassForSameFiles}" ToolTip="Single class generation allows to join similar files and query over them. Might not work well for files with relations">Generate single class for similar files</CheckBox>
+            <CheckBox IsChecked="{Binding DetectRelations}" ToolTip="Detect relations between CSV files/tables (based on files and column names)">Detect relations</CheckBox>
+            <CheckBox IsChecked="{Binding HideRelationsFromDump}" IsEnabled="{Binding DetectRelations}" ToolTip="LINQPad will not show relations content in .Dump(). This prevents from loading too many data" Margin="16,0,0,0">Hide relations from .Dump()</CheckBox>
+            <CheckBox IsChecked="{Binding DebugInfo}" ToolTip="Show additional driver debug info">Debug info</CheckBox>
             <Separator/>
-            <CheckBox IsChecked="{Binding Persist}">Remember this connection</CheckBox>
+            <CheckBox IsChecked="{Binding Persist}" ToolTip="Persist connection">Remember this connection</CheckBox>
             <StackPanel Margin="0,8,0,0" Orientation="Horizontal" HorizontalAlignment="Right">
                 <Button Name="OkButton" Content="OK" Margin="5,0,0,0" Padding="8,3" Width="85" IsDefault="True" Click="OkButton_Click" />
                 <Button Content="Cancel" Margin="5,0,0,0" Padding="8,3" Width="85" IsCancel="True" />
diff --git a/Src/CsvLINQPadDriver/CsvDataContextDriverProperties.cs b/Src/CsvLINQPadDriver/CsvDataContextDriverProperties.cs
index d82c067..d51001d 100644
--- a/Src/CsvLINQPadDriver/CsvDataContextDriverProperties.cs
+++ b/Src/CsvLINQPadDriver/CsvDataContextDriverProperties.cs
@@ -72,6 +72,12 @@ public char? CsvSeparatorChar
             }
         }
 
+        public bool UseSingleClassForSameFiles
+        {
+            get => GetValue(true);
+            set => SetValue(value);
+        }
+
         public bool DetectRelations
         {
             get => GetValue(true);
diff --git a/Src/CsvLINQPadDriver/CsvLINQPadDriver.csproj b/Src/CsvLINQPadDriver/CsvLINQPadDriver.csproj
index e7d5e99..830415a 100644
--- a/Src/CsvLINQPadDriver/CsvLINQPadDriver.csproj
+++ b/Src/CsvLINQPadDriver/CsvLINQPadDriver.csproj
@@ -24,7 +24,7 @@
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <RepositoryUrl>https://github.com/i2van/CsvLINQPadDriver</RepositoryUrl>
     <PackageIcon>NuGetIcon.png</PackageIcon>
-    <PackageReleaseNotes>Updated dependencies.</PackageReleaseNotes>
+    <PackageReleaseNotes>Added single class generation for the similar CSV files.</PackageReleaseNotes>
     <Copyright>Copyright © Martin Dobroucký 2013-2014, Ivan Ivon 2021</Copyright>
     <AssemblyVersion>6.5.0.0</AssemblyVersion>
     <FileVersion>6.5.0.0</FileVersion>
diff --git a/Src/CsvLINQPadDriver/DataModel/CsvDataModelGenerator.cs b/Src/CsvLINQPadDriver/DataModel/CsvDataModelGenerator.cs
index cc59403..98e1301 100644
--- a/Src/CsvLINQPadDriver/DataModel/CsvDataModelGenerator.cs
+++ b/Src/CsvLINQPadDriver/DataModel/CsvDataModelGenerator.cs
@@ -59,6 +59,8 @@ private CsvDatabase CreateModel()
 
             IEnumerable<CsvTable> CreateTables()
             {
+                var tableCodeNames = new Dictionary<string, string>();
+
                 foreach (var file in files.Where(File.Exists))
                 {
                     var csvSeparator = _csvDataContextDriverProperties.CsvSeparatorChar ?? FileUtils.CsvDetectSeparator(file);
@@ -70,25 +72,41 @@ IEnumerable<CsvTable> CreateTables()
 
                     var fileName = Path.GetFileName(file);
                     var fileDir = (Path.GetDirectoryName($"{file.Remove(0, baseDir.Length)}x") ?? string.Empty).TrimStart(Path.DirectorySeparatorChar);
-
-                    yield return new CsvTable
-                    (
-                        file,
-                        csvSeparator,
-                        FileUtils.CsvReadHeader(file, csvSeparator)
-                            .Select((value, index) => (value, index))
-                            .Select(col => new CsvColumn(col.value ?? string.Empty, col.index)
-                                    {
-                                        CodeName = CodeGenHelper.GetSafeCodeName(col.value),
-                                        DisplayName = string.Empty
-                                    }
-                            ).ToList(),
-                        new List<CsvRelation>()
-                    )
+                    var codeName = CodeGenHelper.GetSafeCodeName(Path.GetFileNameWithoutExtension(fileName) + (string.IsNullOrWhiteSpace(fileDir) ? string.Empty : $"_{fileDir}"));
+
+                    var columns = FileUtils.CsvReadHeader(file, csvSeparator)
+                        .Select((value, index) => (value, index))
+                        .Select(col => new CsvColumn(col.value ?? string.Empty, col.index)
+                        {
+                            CodeName = CodeGenHelper.GetSafeCodeName(col.value),
+                            DisplayName = string.Empty
+                        })
+                        .ToList();
+
+                    yield return new CsvTable(file, csvSeparator, columns, new List<CsvRelation>())
                     {
-                        CodeName    = CodeGenHelper.GetSafeCodeName(Path.GetFileNameWithoutExtension(fileName) + (string.IsNullOrWhiteSpace(fileDir) ? string.Empty : $"_{fileDir}")),
+                        CodeName    = codeName,
+                        ClassName   = GetClassName(),
                         DisplayName = $"{fileName}{(string.IsNullOrWhiteSpace(fileDir) ? string.Empty : $" in {fileDir}")} {FileUtils.GetHumanizedFileSize(file)}"
                     };
+
+                    string? GetClassName()
+                    {
+                        if (!_csvDataContextDriverProperties.UseSingleClassForSameFiles)
+                        {
+                            return null;
+                        }
+
+                        var key = string.Join(string.Empty, columns.Select(c => $"{c.CsvColumnName}\t{c.CsvColumnIndex}\n"));
+
+                        if (!tableCodeNames.TryGetValue(key, out var className))
+                        {
+                            className = codeName;
+                            tableCodeNames.Add(key, className);
+                        }
+
+                        return className;
+                    }
                 }
             }
 
diff --git a/Src/CsvLINQPadDriver/DataModel/CsvTable.cs b/Src/CsvLINQPadDriver/DataModel/CsvTable.cs
index 19d824b..0431fac 100644
--- a/Src/CsvLINQPadDriver/DataModel/CsvTable.cs
+++ b/Src/CsvLINQPadDriver/DataModel/CsvTable.cs
@@ -13,5 +13,13 @@ IList<CsvRelation> Relations
     {
         public string? CodeName { get; set; }
         public string? DisplayName { get; set; }
+        
+        public string? ClassName
+        {
+            get => _className ?? CodeName;
+            init => _className = value;
+        }
+
+        private readonly string? _className;
     }
 }
diff --git a/Src/CsvLINQPadDriver/Helpers/FileUtils.cs b/Src/CsvLINQPadDriver/Helpers/FileUtils.cs
index 6852d49..89a8042 100644
--- a/Src/CsvLINQPadDriver/Helpers/FileUtils.cs
+++ b/Src/CsvLINQPadDriver/Helpers/FileUtils.cs
@@ -89,8 +89,8 @@ public static bool IsCsvFormatValid(string fileName, char csvSeparator)
 
                 var headerRow = csvParser.Record;
 
-                // 0 or 1 column.
-                if (headerRow.Length <= 1)
+                // No columns.
+                if (!headerRow.Any())
                 {
                     CsvDataContextDriver.WriteToLog($"{header} CSV header had no columns");
 
diff --git a/Src/CsvLINQPadDriver/ICsvDataContextDriverProperties.cs b/Src/CsvLINQPadDriver/ICsvDataContextDriverProperties.cs
index 85b919e..d84569f 100644
--- a/Src/CsvLINQPadDriver/ICsvDataContextDriverProperties.cs
+++ b/Src/CsvLINQPadDriver/ICsvDataContextDriverProperties.cs
@@ -24,7 +24,12 @@ public interface ICsvDataContextDriverProperties
         char? CsvSeparatorChar { get; }
 
         /// <summary>
-        /// If <c>true</c> - relations between CSV files/tables will be detected and created. (based on files and column names)
+        /// If <c>true</c> - generates single class for similar CSV files.
+        /// </summary>
+        bool UseSingleClassForSameFiles { get; set; }
+
+        /// <summary>
+        /// If <c>true</c> - relations between CSV files/tables will be detected and created. (based on files and column names).
         /// </summary>
         bool DetectRelations { get; set; }
 
diff --git a/Src/CsvLINQPadDriver/SchemaBuilder.cs b/Src/CsvLINQPadDriver/SchemaBuilder.cs
index 5f77d20..751c915 100644
--- a/Src/CsvLINQPadDriver/SchemaBuilder.cs
+++ b/Src/CsvLINQPadDriver/SchemaBuilder.cs
@@ -18,31 +18,52 @@ internal static List<ExplorerItem> GetSchemaAndBuildAssembly(ICsvDataContextDriv
         {
             var csvDatabase = CsvDataModelGenerator.CreateModel(csvDataContextDriverProperties);
 
-            var code = CsvCSharpCodeGenerator.GenerateCode(csvDatabase, ref nameSpace, ref typeName, csvDataContextDriverProperties);
+            var (code, tableCodeGroups) = CsvCSharpCodeGenerator.GenerateCode(csvDatabase, ref nameSpace, ref typeName, csvDataContextDriverProperties);
 
             var compileErrors = BuildAssembly(code, assemblyToBuild);
 
             var schema = GetSchema(csvDatabase);
 
-            var hasCompileErrors = compileErrors.Any();
+            var hasCompilationErrors = compileErrors.Any();
 
-            if (hasCompileErrors || csvDataContextDriverProperties.DebugInfo)
+            var index = 0;
+
+            if (hasCompilationErrors || csvDataContextDriverProperties.DebugInfo)
             {
-                schema.Insert(0, new ExplorerItem("Context Source Code", ExplorerItemKind.Schema, ExplorerIcon.Schema)
+                schema.Insert(index++, new ExplorerItem("Data context source code", ExplorerItemKind.Schema, ExplorerIcon.Schema)
                 {
-                    ToolTipText = "Data Context source code. Drag&drop to text window.",
+                    ToolTipText = "Drag&drop context source code to text window",
                     DragText = code
                 });
             }
 
-            if (hasCompileErrors)
+            if (hasCompilationErrors)
             {
-                schema.Insert(0, new ExplorerItem("Context Compile ERROR", ExplorerItemKind.Schema, ExplorerIcon.Box)
+                schema.Insert(0, new ExplorerItem("Data context compilation failed", ExplorerItemKind.Schema, ExplorerIcon.Box)
                 {
-                    ToolTipText = "Data context compile failed. Drag&Drop error messages to text window to see them",
+                    ToolTipText = "Drag&drop data context compilation errors to text window",
                     DragText = string.Join(Environment.NewLine, compileErrors)
                 });
             }
+            else
+            {
+                foreach (var tableCodeGroup in tableCodeGroups.Where(codeGroup => codeGroup.Count() > 1))
+                {
+                    var codeNames = tableCodeGroup.Select(g => g.CodeName).ToList();
+
+                    var total = $"({codeNames.Count} total)";
+
+                    schema.Insert(index++, new ExplorerItem($"{codeNames.First()} similar files {total} joined data", ExplorerItemKind.Schema, ExplorerIcon.View)
+                    {
+                        ToolTipText = $"Drag&drop similar files {total} joined data to text window{Environment.NewLine}{Environment.NewLine}" +
+                                      $"{string.Join(Environment.NewLine, codeNames.Count <= 3 ? codeNames : codeNames.Take(2).Concat(new []{ "..." }).Concat(codeNames.Skip(codeNames.Count-1)))}",
+                        DragText = $@"new []
+{{
+{string.Join(Environment.NewLine, codeNames.Select(n => $"\t{n},"))}
+}}.SelectMany(_ => _)"
+                    });
+                }
+            }
 
             if (!csvDatabase.Tables.Any())
             {
diff --git a/Tests/CsvLINQPadDriverTest/SchemaBuilderTest.cs b/Tests/CsvLINQPadDriverTest/SchemaBuilderTest.cs
index 3ad934a..e84b6a9 100644
--- a/Tests/CsvLINQPadDriverTest/SchemaBuilderTest.cs
+++ b/Tests/CsvLINQPadDriverTest/SchemaBuilderTest.cs
@@ -20,7 +20,7 @@ public class SchemaBuilderTest
     {
         [Test]
         [TestCaseSource(nameof(CsvDataContextDriverProperties))]
-        public void GetSchemaAndBuildAssembly_CreatedAssembly_AsExpected((ICsvDataContextDriverProperties, string) testData)
+        public void GetSchemaAndBuildAssembly_CreatedAssembly_AsExpected((ICsvDataContextDriverProperties, int) testData)
         {
             var (properties, id) = testData;
 
@@ -80,7 +80,7 @@ ref contextTypeName
             contextType.Should().NotBeNull("ContextType in assembly");
 
             // Check generated context runtime.
-            var contextInstance = contextType!.GetConstructor(new Type[] {})!
+            var contextInstance = contextType!.GetConstructor(new Type[] {})
                 .Should()
                 .NotBeNull()
                 .And
@@ -97,7 +97,7 @@ static IEnumerable<string> Split(string str) =>
                 str.Split(",");
         }
 
-        private static IEnumerable<(ICsvDataContextDriverProperties, string)> CsvDataContextDriverProperties()
+        private static IEnumerable<(ICsvDataContextDriverProperties, int)> CsvDataContextDriverProperties()
         {
             var files = Path.Combine(Directory.GetCurrentDirectory(), "*.csv");
             var parsedFiles = new[] { files };
@@ -107,24 +107,26 @@ static IEnumerable<string> Split(string str) =>
                 Files = files,
                 ParsedFiles = parsedFiles,
                 DebugInfo = true,
+                UseSingleClassForSameFiles = true,
                 DetectRelations = true,
                 IgnoreInvalidFiles = true,
                 IsCacheEnabled = true,
                 HideRelationsFromDump = true,
                 Persist = true
-            }, "1");
+            }, 1);
 
             yield return (new PropertiesMock
             {
                 Files = files,
                 ParsedFiles = parsedFiles,
                 DebugInfo = true,
+                UseSingleClassForSameFiles = true,
                 DetectRelations = true,
                 IgnoreInvalidFiles = false,
                 IsCacheEnabled = false,
                 HideRelationsFromDump = false,
                 Persist = false
-            }, "2");
+            }, 2);
         }
 
         private class PropertiesMock : ICsvDataContextDriverProperties
@@ -134,6 +136,7 @@ private class PropertiesMock : ICsvDataContextDriverProperties
             public IEnumerable<string> ParsedFiles { get; init; } = null!;
             public string CsvSeparator { get; set; } = null!;
             public char? CsvSeparatorChar { get; } = null;
+            public bool UseSingleClassForSameFiles { get; set; }
             public bool DetectRelations { get; set; }
             public bool HideRelationsFromDump { get; set; }
             public bool DebugInfo { get; set; }