Merge pull request #6495 from elsa-workflows/enh/explicit-deterministic-variable-id

Refactor variable initialization for clarity and consistency

src/modules/Elsa.Workflows.Core/Abstractions/WorkflowBase.cs

@@ -52,7 +52,7 @@ public abstract class WorkflowBase<TResult> : WorkflowBase
     /// <inheritdoc />
     protected WorkflowBase()
     {
-        Result = new Variable<TResult>();
+        Result = new("Result", default!);
     }
     
     /// <summary>

src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs

@@ -10,7 +10,7 @@ namespace Elsa.Workflows.Activities;
 public class ParallelForEach : ParallelForEach<object>
 {
     /// <inheritdoc />
-    public ParallelForEach([CallerFilePath] string? source = default, [CallerLineNumber] int? line = default) : base(source, line)
+    public ParallelForEach([CallerFilePath] string? source = null, [CallerLineNumber] int? line = null) : base(source, line)
     {
     }
 }

src/modules/Elsa.Workflows.Core/Activities/ParallelForEachT.cs

@@ -20,7 +20,7 @@ public class ParallelForEach<T> : Activity
     private const string CompletedTagsProperty = nameof(CompletedTagsProperty);
 
     /// <inheritdoc />
-    public ParallelForEach([CallerFilePath] string? source = default, [CallerLineNumber] int? line = default) : base(source, line)
+    public ParallelForEach([CallerFilePath] string? source = null, [CallerLineNumber] int? line = null) : base(source, line)
     {
     }
 
@@ -34,7 +34,7 @@ public class ParallelForEach<T> : Activity
     /// The <see cref="IActivity"/> to execute each iteration.
     /// </summary>
     [Port]
-    public IActivity Body { get; set; } = default!;
+    public IActivity Body { get; set; } = null!;
 
     /// <inheritdoc />
     protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)

src/modules/Elsa.Workflows.Core/Builders/WorkflowBuilder.cs

@@ -72,9 +72,10 @@ public class WorkflowBuilder(IActivityVisitor activityVisitor, IIdentityGraphSer
     }
 
     /// <inheritdoc />
+    [Obsolete("Use the overload that takes a name instead. This overload will be removed in a future version.")]
     public Variable<T> WithVariable<T>()
     {
-        var variable = new Variable<T>();
+        var variable = new Variable<T>(null!, default!);
         Variables.Add(variable);
         variable.WithWorkflowStorage();
         variable.Id = null!; // This ensures that a deterministic ID is assigned by the builder.  
@@ -84,13 +85,13 @@ public class WorkflowBuilder(IActivityVisitor activityVisitor, IIdentityGraphSer
     /// <inheritdoc />
     public Variable<T> WithVariable<T>(string name, T value)
     {
-        var variable = WithVariable<T>();
-        variable.Name = name;
-        variable.Value = value;
+        var variable = new Variable<T>(name, value);
+        Variables.Add(variable);
         return variable;
     }
 
     /// <inheritdoc />
+    [Obsolete("Use the overload that takes a name instead. This overload will be removed in a future version.")]
     public Variable<T> WithVariable<T>(T value)
     {
         var variable = WithVariable<T>();

src/modules/Elsa.Workflows.Core/Memory/Variable.cs

@@ -1,5 +1,7 @@
+using System.Text.Json.Serialization;
 using Elsa.Expressions.Helpers;
 using Elsa.Expressions.Models;
+using Humanizer;
 
 namespace Elsa.Workflows.Memory;
 
@@ -11,19 +13,23 @@ public class Variable : MemoryBlockReference
     /// <inheritdoc />
     public Variable()
     {
-        Id = Guid.NewGuid().ToString("N");
     }
 
     /// <inheritdoc />
-    public Variable(string name) : this()
+    public Variable(string name)
     {
+        Id = GetIdFromName(name);
         Name = name;
     }
 
     /// <inheritdoc />
-    public Variable(string name, object? value = null) : this()
+    public Variable(string name, object? value = null) : this(name)
+    {
+        Value = value;
+    }
+    
+    public Variable(string name, object? value = null, string? id = null) : this(name, value)
     {
-        Name = name;
         Value = value;
     }
 
@@ -45,6 +51,8 @@ public class Variable : MemoryBlockReference
 
     /// <inheritdoc />
     public override MemoryBlock Declare() => new(Value, new VariableBlockMetadata(this, StorageDriverType, false));
+
+    private string GetIdFromName(string? name) => $"{name?.Camelize() ?? "Unnamed"}{nameof(Variable)}";
 }
 
 /// <summary>
@@ -59,16 +67,19 @@ public class Variable<T> : Variable
     }
 
     /// <inheritdoc />
+    [Obsolete("Use the constructor that takes a name parameter instead.", true)]
     public Variable(T value)
     {
         Value = value;
     }
 
     /// <inheritdoc />
-    public Variable(string name, T value)
+    public Variable(string name, T value) : base(name, value)
+    {
+    }
+    
+    public Variable(string name, T value, string? id = null) : base(name, value, id)
     {
-        Name = name;
-        Value = value;
     }
 
     /// <summary>
@@ -95,6 +106,18 @@ public class Variable<T> : Variable
         Id = id;
         return this;
     }
+    
+    public Variable<T> WithName(string name)
+    {
+        Name = name;
+        return this;
+    }
+    
+    public Variable<T> WithValue(T value)
+    {
+        Value = value;
+        return this;
+    }
 }
 
 /// <summary>

test/component/Elsa.Workflows.ComponentTests/Scenarios/JavaScriptVariables/JavaScriptVariablesWorkflow1.cs

@@ -11,6 +11,6 @@ public class JavaScriptVariablesWorkflow1 : WorkflowBase
     {
         builder.WithDefinitionId(DefinitionId);
         builder.WithVariable("MagicNumber", 3).WithWorkflowStorage();
-        builder.Root = new RunJavaScript("setMagicNumber(42)", default, default);
+        builder.Root = new RunJavaScript("setMagicNumber(42)", null, null);
     }
 }

test/component/Elsa.Workflows.ComponentTests/Scenarios/JavaScriptVariables/JavaScriptVariablesWorkflow2.cs

@@ -11,6 +11,6 @@ public class JavaScriptVariablesWorkflow2 : WorkflowBase
     {
         builder.WithDefinitionId(DefinitionId);
         builder.WithVariable("MagicNumber", 3).WithWorkflowStorage();
-        builder.Root = new RunJavaScript("variables.MagicNumber = 42", default, default);
+        builder.Root = new RunJavaScript("variables.MagicNumber = 42", null, null);
     }
 }

test/component/Elsa.Workflows.ComponentTests/Scenarios/JavaScriptVariables/JavaScriptVariablesWorkflow3.cs

@@ -11,6 +11,6 @@ public class JavaScriptVariablesWorkflow3 : WorkflowBase
     {
         builder.WithDefinitionId(DefinitionId);
         builder.WithVariable("MagicNumber", 3).WithWorkflowStorage();
-        builder.Root = new RunJavaScript("setVariable('MagicNumber', 42)", default, default);
+        builder.Root = new RunJavaScript("setVariable('MagicNumber', 42)", null, null);
     }
 }

test/component/Elsa.Workflows.ComponentTests/Scenarios/JavaScriptVariables/JavaScriptVariablesWorkflowTests.cs

@@ -30,7 +30,7 @@ public class JavaScriptVariablesWorkflowTests(App app) : AppComponentTest(app)
         var workflowState = workflowInstance!.WorkflowState;
         var rootWorkflowActivityExecutionContext = workflowState.ActivityExecutionContexts.Single(x => x.ParentContextId == null);
         var variables = GetVariablesDictionary(rootWorkflowActivityExecutionContext);
-        var magicNumber = variables["Workflow1:variable-1"].ConvertTo<int>();
+        var magicNumber = variables["magicNumberVariable"].ConvertTo<int>();
         Assert.Equal(42, magicNumber);
     }
 

test/component/Elsa.Workflows.ComponentTests/Scenarios/Variables/CountdownWorkflowTests.cs

@@ -1,3 +1,4 @@
+using Elsa.Common.Models;
 using Elsa.Expressions.Helpers;
 using Elsa.Extensions;
 using Elsa.Workflows.ComponentTests.Abstractions;
@@ -25,11 +26,11 @@ public class CountdownWorkflowTests(App app) : AppComponentTest(app)
         var bookmarkStore = Scope.ServiceProvider.GetRequiredService<IBookmarkStore>();
         var runAndCreateRequest = new CreateAndRunWorkflowInstanceRequest
         {
-            WorkflowDefinitionHandle = WorkflowDefinitionHandle.ByDefinitionId(CountdownWorkflow.DefinitionId),
+            WorkflowDefinitionHandle = WorkflowDefinitionHandle.ByDefinitionId(CountdownWorkflow.DefinitionId, VersionOptions.Latest),
         };
         var runResponse = await workflowClient.CreateAndRunInstanceAsync(runAndCreateRequest);
         var workflowInstanceId = runResponse.WorkflowInstanceId;
-        var createdBookmarks = await bookmarkStore.FindManyAsync(new BookmarkFilter
+        var createdBookmarks = await bookmarkStore.FindManyAsync(new()
         {
             WorkflowInstanceId = workflowInstanceId
         });
@@ -42,7 +43,7 @@ public class CountdownWorkflowTests(App app) : AppComponentTest(app)
             var workflowState = workflowInstance!.WorkflowState;
             var rootWorkflowActivityExecutionContext = workflowState.ActivityExecutionContexts.Single(x => x.ParentContextId == null);
             var variables = GetVariablesDictionary(rootWorkflowActivityExecutionContext);
-            var actualCounter = variables["Workflow1:variable-1"].ConvertTo<int>();
+            var actualCounter = variables["counterVariable"].ConvertTo<int>();
             Assert.Equal(--expectedCounter, actualCounter);
 
             var bookmark = bookmarks.Pop();
@@ -53,7 +54,7 @@ public class CountdownWorkflowTests(App app) : AppComponentTest(app)
             
             await workflowClient.RunInstanceAsync(runRequest);
 
-            createdBookmarks = await bookmarkStore.FindManyAsync(new BookmarkFilter
+            createdBookmarks = await bookmarkStore.FindManyAsync(new()
             {
                 WorkflowInstanceId = workflowInstanceId
             });

test/integration/Elsa.JavaScript.IntegrationTests/JsonElementConverterTests.cs

@@ -17,12 +17,8 @@ public class JsonElementConverterTests(ITestOutputHelper testOutputHelper)
     public async Task TestJsonObjectPassedAsJsonElement()
     {
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
-        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
-        var jsonVariable = new Variable<object>
-        {
-            Name = "JsonVariable"
-        };
-
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var jsonVariable = new Variable<object>("JsonVariable", "");
         var jsonString = "{\"name\": \"John\", \"age\": 30}";
         var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonString);
 
@@ -36,12 +32,8 @@ public class JsonElementConverterTests(ITestOutputHelper testOutputHelper)
     public async Task TestJsonArrayPassedAsJsonElement()
     {
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
-        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
-        var jsonVariable = new Variable<object>
-        {
-            Name = "JsonVariable"
-        };
-
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var jsonVariable = new Variable<object>("JsonVariable", "");
         var jsonString = "[1, 2, 3, 4, 5, 6]";
         var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonString);
 
@@ -55,12 +47,8 @@ public class JsonElementConverterTests(ITestOutputHelper testOutputHelper)
     public async Task TestStringPassedAsJsonElement()
     {
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
-        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
-        var jsonVariable = new Variable<object>
-        {
-            Name = "JsonVariable"
-        };
-
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var jsonVariable = new Variable<object>("JsonVariable", "");
         var jsonString = "\"I'm just a string\"";
         var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonString);
 
@@ -74,12 +62,8 @@ public class JsonElementConverterTests(ITestOutputHelper testOutputHelper)
     public async Task TestBooleanPassedAsJsonElement()
     {
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
-        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
-        var jsonVariable = new Variable<object>
-        {
-            Name = "JsonVariable"
-        };
-
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var jsonVariable = new Variable<object>("JsonVariable", "");
         var jsonString = "false";
         var jsonElement = JsonSerializer.Deserialize<JsonElement>(jsonString);
 
@@ -93,11 +77,8 @@ public class JsonElementConverterTests(ITestOutputHelper testOutputHelper)
     public async Task TestNestedJsonPassedAsJsonElement()
     {
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
-        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
-        var jsonVariable = new Variable<object>
-        {
-            Name = "JsonVariable"
-        };
+        var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new());
+        var jsonVariable = new Variable<object>("JsonVariable", "");
 
         var jsonString = @"
         {

test/integration/Elsa.JavaScript.IntegrationTests/ToJsonTests.cs

@@ -31,10 +31,7 @@ public class ToJsonTests(ITestOutputHelper testOutputHelper)
         var javaScriptEvaluator = _serviceProvider.GetRequiredService<IJavaScriptEvaluator>();
         var expressionExecutionContext = new ExpressionExecutionContext(_serviceProvider, new MemoryRegister());
         var unicodeString = UnicodeRangeGenerator.GenerateUnicodeString();
-        var payloadVariable = new Variable<object>
-        {
-            Name = "Payload"
-        };
+        var payloadVariable = new Variable<object>("Payload", null!);
         var payload = new
         {
             Text = unicodeString

test/integration/Elsa.Workflows.IntegrationTests/Activities/Break/Workflows/BreakForEachWorkflow.cs

@@ -1,6 +1,5 @@
 using Elsa.Workflows.Activities;
 using Elsa.Workflows.Memory;
-using Elsa.Workflows.Models;
 
 namespace Elsa.Workflows.IntegrationTests.Activities.Workflows;
 
@@ -9,7 +8,7 @@ class BreakForEachWorkflow : WorkflowBase
     protected override void Build(IWorkflowBuilder workflow)
     {
         var items = new[] { "C#", "Rust", "Go" };
-        var currentItem = new Variable<string>();
+        var currentItem = new Variable<string>("CurrentItem", "");
 
         workflow.Root = new Sequence
         {
@@ -18,7 +17,7 @@ class BreakForEachWorkflow : WorkflowBase
                 new WriteLine("Start"),
                 new ForEach<string>
                 {
-                    Items = new Input<ICollection<string>>(items),
+                    Items = new(items),
                     CurrentValue = new (currentItem),
                     Body = new Sequence
                     {

test/integration/Elsa.Workflows.IntegrationTests/Activities/Break/Workflows/BreakForWorkflow.cs

@@ -7,7 +7,7 @@ class BreakForWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>();
+        var currentValue = new Variable<int?>("CurrentValue", null);
 
         workflow.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Activities/Break/Workflows/BreakWhileForkWorkflow.cs

@@ -8,11 +8,7 @@ public class BreakWhileForkWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>
-        {
-            Name = "CurrentValue",
-            Value = 0
-        };
+        var currentValue = new Variable<int?>("CurrentValue", 0);
 
         workflow.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Activities/Break/Workflows/BreakWhileWorkflow.cs

@@ -7,7 +7,7 @@ public class BreakWhileWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>(0);
+        var currentValue = new Variable<int?>("CurrentValue", 0);
 
         workflow.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Activities/ForEach/ForEachWorkflow.cs

@@ -1,6 +1,5 @@
 using Elsa.Workflows.Activities;
 using Elsa.Workflows.Memory;
-using Elsa.Workflows.Models;
 
 namespace Elsa.Workflows.IntegrationTests.Activities;
 
@@ -15,10 +14,7 @@ class ForEachWorkflow : WorkflowBase
 
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentItem = new Variable<string>
-        {
-            Name = "CurrentItem"
-        };
+        var currentItem = new Variable<string>("CurrentItem", "");
 
         workflow.Root = new Sequence
         {
@@ -27,8 +23,8 @@ class ForEachWorkflow : WorkflowBase
             {
                 new ForEach<string>
                 {
-                    Items = new Input<ICollection<string>>(_items),
-                    CurrentValue = new Output<string?>(currentItem),
+                    Items = new(_items),
+                    CurrentValue = new(currentItem),
                     Body = new WriteLine(currentItem)
                 },
             }

test/integration/Elsa.Workflows.IntegrationTests/Activities/ForEach/NestedForEachWithBreakWorkflow.cs

@@ -9,8 +9,8 @@ class NestedForEachWithBreakWorkflow : WorkflowBase
     {
         var outerItems = new[] { "C#", "Rust", "Go" };
         var innerItems = new[] { "Classes", "Functions", "Modules" };
-        var currentOuterItem = new Variable<string>();
-        var currentInnerItem = new Variable<string>();
+        var currentOuterItem = new Variable<string>("CurrentOuterItem", "");
+        var currentInnerItem = new Variable<string>("CurrentInnerItem", "");
 
         workflow.Root = new ForEach<string>(outerItems)
         {

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/ActivityOutputs/SumWorkflow.cs

@@ -8,8 +8,8 @@ public class SumWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var a = new Variable<int>();
-        var b = new Variable<int>();
+        var a = new Variable<int>("A", 0);
+        var b = new Variable<int>("B", 0);
 
         var sumActivity = new SumActivity(a, b);
 

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows/BreakWhileFromForkWorkflow.cs

@@ -8,7 +8,7 @@ public class BreakWhileFromForkWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>(0);
+        var currentValue = new Variable<int?>("CurrentValue", 0);
 
         workflow.WithVariable(currentValue);
 

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows/WaitAllForkWorkflow.cs

@@ -8,7 +8,7 @@ public class WaitAllForkWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>(0);
+        var currentValue = new Variable<int?>("CurrentValue", 0);
 
         workflow.WithVariable(currentValue);
 

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/BlockingAndBreaking/Workflows/WaitAnyForkWorkflow.cs

@@ -8,7 +8,7 @@ public class WaitAnyForkWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var currentValue = new Variable<int?>(0);
+        var currentValue = new Variable<int?>("CurrentValue", 0);
 
         workflow.WithVariable(currentValue);
 

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/Composites/Workflows.cs

@@ -13,12 +13,12 @@ public class Sum : Composite<int>
 {
     private readonly RunJavaScript _runJavaScript;
 
-    public Input<int> A { get; set; } = default!;
-    public Input<int> B { get; set; } = default!;
+    public Input<int> A { get; set; } = null!;
+    public Input<int> B { get; set; } = null!;
 
     public Sum()
     {
-        _runJavaScript = new RunJavaScript
+        _runJavaScript = new()
         {
             Script = new("getA() + getB();"),
         };
@@ -42,7 +42,7 @@ public class Sum : Composite<int>
 
         // If the call site set a result variable, assign it to the JavaScript activity's result.
         if (Result != null)
-            _runJavaScript.Result = new Output<object>(Result.MemoryBlockReference)!;
+            _runJavaScript.Result = new(Result.MemoryBlockReference)!;
     }
 }
 
@@ -53,11 +53,10 @@ public class SumWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var sum = new Variable<int>();
+        var sum = workflow.WithVariable<int>("Sum", 0);
 
         workflow.Root = new Sequence
         {
-            Variables = { sum },
             Activities =
             {
                 new Sum

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/HttpRequestWithLiquid/JavascriptAndLiquidWorkflow.cs

@@ -12,8 +12,8 @@ public class JavascriptAndLiquidWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder builder)
     {
-        var products = new Variable<object> { Name = "Products", StorageDriverType = typeof(WorkflowInstanceStorageDriver) };
-        var product = new Variable<object> { Name = "Product", StorageDriverType = typeof(WorkflowInstanceStorageDriver) };
+        var products = new Variable<object>("Products", null!).WithStorageDriver<WorkflowInstanceStorageDriver>();
+        var product = new Variable<object>("Product", null!).WithStorageDriver<WorkflowInstanceStorageDriver>();
 
         builder.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/ImplicitJoins/ParallelJoinCompletesTests.cs

@@ -24,13 +24,13 @@ public class ParallelJoinCompletesTests
         await _services.PopulateRegistriesAsync();
 
         // Import workflow.
-        var workflowDefinition = await _services.ImportWorkflowDefinitionAsync($"Scenarios/ImplicitJoins/Workflows/parallel-join.json");
+        var workflowDefinition = await _services.ImportWorkflowDefinitionAsync("Scenarios/ImplicitJoins/Workflows/parallel-join.json");
 
         // Execute.
         var state = await _services.RunWorkflowUntilEndAsync(workflowDefinition.DefinitionId);
         
         // Assert.
-        var journal = await _services.GetRequiredService<IWorkflowExecutionLogStore>().FindManyAsync(new WorkflowExecutionLogRecordFilter
+        var journal = await _services.GetRequiredService<IWorkflowExecutionLogStore>().FindManyAsync(new()
         {
             WorkflowInstanceId = state.Id,
             ActivityId = "70fc1183cd5800f2",

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/SetGetVariables/Workflows.cs

@@ -8,7 +8,7 @@ class SetGetVariableWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var variable1 = new Variable<string>();
+        var variable1 = new Variable<string>("Variable1", "");
 
         workflow.Root = new Sequence
         {
@@ -30,8 +30,8 @@ class SetGetVariablesWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var variable1 = new Variable<string>();
-        var variable2 = new Variable<string>();
+        var variable1 = new Variable<string>("Variable1", "");
+        var variable2 = new Variable<string>("Variable2", "");
 
         workflow.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/SetGetVariablesFromActivities/Workflows/SampleWorkflow.cs

@@ -8,7 +8,7 @@ class SampleWorkflow : WorkflowBase
 {
     protected override void Build(IWorkflowBuilder workflow)
     {
-        var variable1 = new Variable<string>();
+        var variable1 = new Variable<string>("Variable1", "");
 
         workflow.Root = new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/WorkflowResults/Tests.cs

@@ -23,7 +23,7 @@ public class Tests
     {
         await _services.PopulateRegistriesAsync();
         var expectedValue = "Some value";
-        var variable1 = new Variable();
+        var variable1 = new Variable("Variable1");
         
         var workflow = Workflow.FromActivity(new Sequence
         {
@@ -46,7 +46,7 @@ public class Tests
     {
         await _services.PopulateRegistriesAsync();
         var expectedValue = "Some value";
-        var variable = new Variable<string>();
+        var variable = new Variable<string>("Variable", "");
         
         var workflow = Workflow.FromActivity(new Sequence
         {

test/integration/Elsa.Workflows.IntegrationTests/Serialization/VariableTypes/Tests.cs

@@ -24,7 +24,7 @@ public class Tests
         var model = new VariablesContainer(variables);
         
         // Create a typed variable.
-        var variable = new Variable<bool>();
+        var variable = new Variable<bool>("Variable", false);
         
         // Add variable to collection.
         variables.Add(variable);