feat: unified Node model & FUnit testing framework

Directory.Build.targets

@@ -24,8 +24,11 @@
     <!-- Add Flowthru ProjectReferences -->
     <ProjectReference Include="$(RepoRoot)src\core\Flowthru\Flowthru.csproj" />
 
-    <!-- Add source generator references directly for local development -->
-    <ProjectReference Include="$(RepoRoot)src\core\Flowthru.SourceGenerators\Flowthru.SourceGenerators.csproj"
+    <!-- Add source generator and code fix references directly for local development -->
+    <ProjectReference Include="$(RepoRoot)src\core\Flowthru.Core.SourceGenerators\Flowthru.Core.SourceGenerators.csproj"
+                      ReferenceOutputAssembly="false"
+                      OutputItemType="Analyzer" />
+    <ProjectReference Include="$(RepoRoot)src\core\Flowthru.Core.CodeFixes\Flowthru.Core.CodeFixes.csproj"
                       ReferenceOutputAssembly="false"
                       OutputItemType="Analyzer" />
 
@@ -50,4 +53,27 @@
     <ProjectReference Include="$(RepoRoot)src\core\Flowthru\Flowthru.csproj" />
   </ItemGroup>
 
+  <!--
+    For projects that explicitly depend on Flowthru.FUnit (opt-in, not universal):
+    remove any PackageReference and wire up the source + analyzer projects directly.
+    FUnit generators emit code that imports Flowthru.FUnit types, so this injection
+    must NOT be applied globally — only for projects that already reference FUnit.
+  -->
+  <ItemGroup Condition="($(MSBuildProjectDirRelativePath.StartsWith('examples')) OR $(MSBuildProjectDirRelativePath.StartsWith('tests'))) AND '$(MSBuildProjectName)' != 'Flowthru.FUnit'">
+    <PackageReference Remove="Flowthru.FUnit" />
+  </ItemGroup>
+
+  <ItemGroup Condition="($(MSBuildProjectDirRelativePath.StartsWith('examples')) OR $(MSBuildProjectDirRelativePath.StartsWith('tests'))) AND Exists('$(RepoRoot)src\core\Flowthru.FUnit\Flowthru.FUnit.csproj') AND '$(MSBuildProjectName)' != 'Flowthru.FUnit'">
+    <!-- Replace PackageReference to Flowthru.FUnit with in-repo sources where applicable.
+         The Exists() on the PackageReference Remove above gates whether any replacement is needed. -->
+    <ProjectReference Include="$(RepoRoot)src\core\Flowthru.FUnit.SourceGenerators\Flowthru.FUnit.SourceGenerators.csproj"
+                      ReferenceOutputAssembly="false"
+                      OutputItemType="Analyzer"
+                      Condition="'$(MSBuildProjectName)' == 'KedroIrisFUnit' OR $(MSBuildProjectDirRelativePath.Contains('FUnit'))" />
+    <ProjectReference Include="$(RepoRoot)src\core\Flowthru.FUnit.CodeFixes\Flowthru.FUnit.CodeFixes.csproj"
+                      ReferenceOutputAssembly="false"
+                      OutputItemType="Analyzer"
+                      Condition="'$(MSBuildProjectName)' == 'KedroIrisFUnit' OR $(MSBuildProjectDirRelativePath.Contains('FUnit'))" />
+  </ItemGroup>
+
 </Project>

Flowthru.slnx

@@ -2,7 +2,11 @@
   <Folder Name="/src/">
     <Project Path="src\core\Flowthru\Flowthru.csproj" />
     <Project Path="src\core\Flowthru.Core\Flowthru.Core.csproj" />
-    <Project Path="src\core\Flowthru.SourceGenerators\Flowthru.SourceGenerators.csproj" />
+    <Project Path="src\core\Flowthru.Core.SourceGenerators\Flowthru.Core.SourceGenerators.csproj" />
+    <Project Path="src\core\Flowthru.FUnit\Flowthru.FUnit.csproj" />
+    <Project Path="src\core\Flowthru.FUnit.SourceGenerators\Flowthru.FUnit.SourceGenerators.csproj" />
+    <Project Path="src\core\Flowthru.Core.CodeFixes\Flowthru.Core.CodeFixes.csproj" />
+    <Project Path="src\core\Flowthru.FUnit.CodeFixes\Flowthru.FUnit.CodeFixes.csproj" />
     <Project Path="src\extensions\Flowthru.Extensions.Csv\Flowthru.Extensions.Csv.csproj" />
     <Project Path="src\extensions\Flowthru.Extensions.Excel\Flowthru.Extensions.Excel.csproj" />
     <Project Path="src\extensions\Flowthru.Extensions.EFCore\Flowthru.Extensions.EFCore.csproj" />
@@ -17,14 +21,17 @@
     <Project Path="tests\Flowthru.Tests.Common\Flowthru.Tests.Common.csproj" />
     <Project Path="tests\Flowthru.Tests.Examples\Flowthru.Tests.Examples.csproj" />
     <Project Path="tests\Flowthru.Tests.Templates\Flowthru.Tests.Templates.csproj" />
+    <Project Path="tests\Flowthru.FUnit.Tests\Flowthru.FUnit.Tests.csproj" />
     <Project Path="tests\Flowthru.Extensions.Python.Tests\Flowthru.Extensions.Python.Tests.csproj" />
     <Project Path="tests\Flowthru.Extensions.EFCore.Tests\Flowthru.Extensions.EFCore.Tests.csproj" />
   </Folder>
   <Folder Name="/examples/">
     <Project Path="examples\starter\SpaceflightsEFCore\SpaceflightsEFCore.csproj" />
     <Project Path="examples\starter\KedroSpaceflights\KedroSpaceflights.csproj" />
+    <Project Path="examples\starter\KedroSpaceflightsFUnit\KedroSpaceflightsFUnit.csproj" />
     <Project Path="examples\starter\KedroSpaceflightsPython\KedroSpaceflightsPython.csproj" />
     <Project Path="examples\starter\KedroIris\KedroIris.csproj" />
+    <Project Path="examples\starter\KedroIrisFUnit\KedroIrisFUnit.csproj" />
     <Project Path="examples\starter\KedroIrisPython\KedroIrisPython.csproj" />
     <Project Path="examples\starter\Minimal\Minimal.csproj" />
     <Project Path="examples\archived\UmapReferenceComparisons\UmapReferenceComparisons.csproj" />

docs/reference/misc/external/bunit/.source.env

@@ -0,0 +1,2 @@
+SOURCE_TYPE=repo
+SOURCE_ADDRESS=https://github.com/bUnit-dev/bUnit.git

docs/reference/misc/external/roslyn/.source.env

@@ -0,0 +1,2 @@
+SOURCE_TYPE=repo
+SOURCE_ADDRESS=https://github.com/dotnet/roslyn.git

examples/advanced/KedroSpaceflights.Custom/Data/Catalog.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 
 namespace KedroSpaceflights.Custom.Data;
 

examples/advanced/KedroSpaceflights.Custom/Data/_01_Raw/Catalog.Raw.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_01_Raw/Schemas/CompanyRawSchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_01_Raw/Schemas/KedroModelInputSchema.cs

@@ -1,5 +1,5 @@
-using Flowthru.Abstractions;
-using Flowthru.Data;
+using Flowthru.Core.Abstractions;
+using Flowthru.Core.Data;
 
 namespace KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_01_Raw/Schemas/ReviewRawSchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_01_Raw/Schemas/ShuttleRawSchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_02_Intermediate/Catalog.Intermediate.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 
 namespace KedroSpaceflights.Custom.Data;

examples/advanced/KedroSpaceflights.Custom/Data/_02_Intermediate/Schemas/CompanySchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_02_Intermediate/Schemas/ReviewSchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_02_Intermediate/Schemas/ShuttleSchema.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_03_Primary/Catalog.Primary.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Flows.DataScience.Steps;
 

examples/advanced/KedroSpaceflights.Custom/Data/_03_Primary/Schemas/FeatureRow.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_03_Primary/Schemas/ModelInputSchema.cs

@@ -1,5 +1,5 @@
-using Flowthru.Abstractions;
-using Flowthru.Data;
+using Flowthru.Core.Abstractions;
+using Flowthru.Core.Data;
 
 namespace KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_03_Primary/Schemas/TargetValue.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_04_Models/Catalog.Models.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._04_Models.Schemas;
 
 namespace KedroSpaceflights.Custom.Data;

examples/advanced/KedroSpaceflights.Custom/Data/_04_Models/Schemas/LinearRegressionModel.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 
 namespace KedroSpaceflights.Custom.Data._04_Models.Schemas;

examples/advanced/KedroSpaceflights.Custom/Data/_05_ModelOutput/Catalog.ModelOutput.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._05_ModelOutput.Schemas;
 
 namespace KedroSpaceflights.Custom.Data;

examples/advanced/KedroSpaceflights.Custom/Data/_05_ModelOutput/Schemas/ModelMetrics.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._05_ModelOutput.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_05_ModelOutput/Schemas/ModelPredictions.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._05_ModelOutput.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Data/_06_Reporting/Catalog.Reporting.cs

@@ -1,4 +1,4 @@
-using Flowthru.Data;
+using Flowthru.Core.Data;
 using KedroSpaceflights.Custom.Data._06_Reporting.Schemas;
 using Plotly.NET;
 

examples/advanced/KedroSpaceflights.Custom/Data/_06_Reporting/Schemas/CrossValidationSchemas.cs

@@ -1,4 +1,4 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Abstractions;
 
 namespace KedroSpaceflights.Custom.Data._06_Reporting.Schemas;
 

examples/advanced/KedroSpaceflights.Custom/Flows/DataDiagnostics/DataDiagnosticsFlow.cs

@@ -1,5 +1,5 @@
-using Flowthru.Flows;
-using Flowthru.Steps;
+using Flowthru.Core.Flows;
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;

examples/advanced/KedroSpaceflights.Custom/Flows/DataDiagnostics/Steps/PassthroughInputToOutputStep.cs

@@ -1,3 +1,5 @@
+using Flowthru.Core.Steps;
+
 namespace KedroSpaceflights.Custom.Flows.DataDiagnostics.Steps;
 
 /// <summary>
@@ -8,6 +10,7 @@ namespace KedroSpaceflights.Custom.Flows.DataDiagnostics.Steps;
 /// This is a diagnostic node that simply passes data through while writing
 /// it to a CSV catalog entry. Useful for debugging pipeline data issues.
 /// </remarks>
+[FlowthruStep]
 public static class PassthroughInputToOutputStep<T>
 {
   public static Func<IEnumerable<T>, Task<IEnumerable<T>>> Create()

examples/advanced/KedroSpaceflights.Custom/Flows/DataDiagnostics/Steps/ValidateAgainstKedroStep.cs

@@ -1,5 +1,5 @@
 using System.Reflection;
-using Flowthru.Steps;
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 
@@ -20,6 +20,7 @@ namespace KedroSpaceflights.Custom.Flows.DataDiagnostics.Steps;
 /// but logs detailed comparison results for diagnostic purposes.
 /// </para>
 /// </remarks>
+[FlowthruStep]
 public static class ValidateAgainstKedroStep
 {
   public static Func<

examples/advanced/KedroSpaceflights.Custom/Flows/DataEvaluation/DataEvaluationFlow.cs

@@ -1,5 +1,5 @@
-using Flowthru.Flows;
-using Flowthru.Steps;
+using Flowthru.Core.Flows;
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Data._04_Models.Schemas;

examples/advanced/KedroSpaceflights.Custom/Flows/DataEvaluation/Steps/CrossValidateModelStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using System.ComponentModel.DataAnnotations;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Data._06_Reporting.Schemas;
@@ -10,6 +11,7 @@ namespace KedroSpaceflights.Custom.Flows.DataEvaluation.Steps;
 /// Performs k-fold cross-validation to generate R² distribution.
 /// Helps understand model stability and variance across different train/test splits.
 /// </summary>
+[FlowthruStep]
 public static class CrossValidateModelStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataEvaluation/Steps/EvaluateModelStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Data._04_Models.Schemas;
 using KedroSpaceflights.Custom.Data._05_ModelOutput.Schemas;
@@ -11,6 +12,7 @@ namespace KedroSpaceflights.Custom.Flows.DataEvaluation.Steps;
 /// Evaluates the trained OLS regression model on test data and logs metrics.
 /// Uses Math.NET Numerics GoodnessOfFit.RSquared() matching sklearn's r2_score.
 /// </summary>
+[FlowthruStep]
 public static class EvaluateModelStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataProcessing/DataProcessingFlow.cs

@@ -1,4 +1,4 @@
-using Flowthru.Flows;
+using Flowthru.Core.Flows;
 using KedroSpaceflights.Custom.Data;
 using KedroSpaceflights.Custom.Flows.DataProcessing.Steps;
 

examples/advanced/KedroSpaceflights.Custom/Flows/DataProcessing/Steps/CreateModelInputTableStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 
@@ -8,6 +9,7 @@ namespace KedroSpaceflights.Custom.Flows.DataProcessing.Steps;
 /// Performs inner joins on validated, non-nullable data.
 /// All null filtering is handled upstream in preprocessing nodes.
 /// </summary>
+[FlowthruStep]
 public static class CreateModelInputTableStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataProcessing/Steps/PreprocessCompaniesStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 
@@ -7,6 +8,7 @@ namespace KedroSpaceflights.Custom.Flows.DataProcessing.Steps;
 /// Preprocesses raw company data by converting string values to proper types.
 /// Converts percentage strings to decimals and "t"/"f" to booleans.
 /// </summary>
+[FlowthruStep]
 public static class PreprocessCompaniesStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataProcessing/Steps/PreprocessReviewsStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 
@@ -7,6 +8,7 @@ namespace KedroSpaceflights.Custom.Flows.DataProcessing.Steps;
 /// Preprocesses raw review data by converting string values to proper types and filtering out incomplete records.
 /// Converts string scores to decimals and drops rows with missing required fields.
 /// </summary>
+[FlowthruStep]
 public static class PreprocessReviewsStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataProcessing/Steps/PreprocessShuttlesStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._01_Raw.Schemas;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 
@@ -7,6 +8,7 @@ namespace KedroSpaceflights.Custom.Flows.DataProcessing.Steps;
 /// Preprocesses raw shuttle data by converting string values to proper types.
 /// Converts price strings ($1,234,567) to decimals and "t"/"f" to booleans.
 /// </summary>
+[FlowthruStep]
 public static class PreprocessShuttlesStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/DataScience/DataScienceFlow.cs

@@ -1,4 +1,4 @@
-using Flowthru.Flows;
+using Flowthru.Core.Flows;
 using KedroSpaceflights.Custom.Data;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Flows.DataEvaluation.Steps;

examples/advanced/KedroSpaceflights.Custom/Flows/DataScience/Steps/CreateTestTrainSplitStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 
 namespace KedroSpaceflights.Custom.Flows.DataScience.Steps;
@@ -6,6 +7,7 @@ namespace KedroSpaceflights.Custom.Flows.DataScience.Steps;
 /// Splits model input data into training and testing sets.
 /// Extracts features and target variable (price) for ML training.
 /// </summary>
+[FlowthruStep]
 public static class CreateTestTrainSplitStep
 {
   // Following FlowThru's artifact colocation policy:

examples/advanced/KedroSpaceflights.Custom/Flows/DataScience/Steps/TrainModelStep.cs

@@ -1,4 +1,5 @@
-using Flowthru.Abstractions;
+using Flowthru.Core.Steps;
+using Flowthru.Core.Abstractions;
 using KedroSpaceflights.Custom.Data._03_Primary.Schemas;
 using KedroSpaceflights.Custom.Data._04_Models.Schemas;
 using MathNet.Numerics;
@@ -12,6 +13,7 @@ namespace KedroSpaceflights.Custom.Flows.DataScience.Steps;
 /// Uses Math.NET Numerics MultipleRegression.QR() which matches sklearn's LinearRegression.
 /// Takes training features (x_train) and targets (y_train) as separate inputs.
 /// </summary>
+[FlowthruStep]
 public static class TrainModelStep
 {
   /// <summary>

examples/advanced/KedroSpaceflights.Custom/Flows/Reporting/ReportingFlow.cs

@@ -1,5 +1,5 @@
-using Flowthru.Flows;
-using Flowthru.Steps;
+using Flowthru.Core.Flows;
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data;
 using KedroSpaceflights.Custom.Flows.Reporting.Steps;
 

examples/advanced/KedroSpaceflights.Custom/Flows/Reporting/Steps/ComparePassengerCapacityStep.cs

@@ -1,3 +1,4 @@
+using Flowthru.Core.Steps;
 using KedroSpaceflights.Custom.Data._02_Intermediate.Schemas;
 using Microsoft.Extensions.Logging;
 using Plotly.NET;
@@ -28,6 +29,7 @@ namespace KedroSpaceflights.Custom.Flows.Reporting.Steps;
 /// separation of concerns and reusable export pipelines.
 /// </para>
 /// </remarks>
+[FlowthruStep]
 public static class ComparePassengerCapacityStep
 {
   public static Func<IEnumerable<ShuttleSchema>, Task<GenericChart>> Create(ILogger? logger = null)