Workflow flow.

src/Squidex.Domain.Apps.Core.Model/Apps/Role.cs

@@ -90,6 +90,7 @@ namespace Squidex.Domain.Apps.Core.Apps
                 P.ForApp(P.AppCommon, app),
                 P.ForApp(P.AppContents, app),
                 P.ForApp(P.AppPatterns, app),
+                P.ForApp(P.AppWorkflows, app),
                 P.ForApp(P.AppRules, app),
                 P.ForApp(P.AppSchemas, app));
         }

src/Squidex.Domain.Apps.Core.Model/Contents/Workflow.cs

@@ -12,6 +12,8 @@ namespace Squidex.Domain.Apps.Core.Contents
 {
     public sealed class Workflow
     {
+        public static readonly IReadOnlyDictionary<Status, WorkflowStep> EmptySteps = new Dictionary<Status, WorkflowStep>();
+
         public static readonly Workflow Default = new Workflow(
             new Dictionary<Status, WorkflowStep>
             {

src/Squidex.Domain.Apps.Core.Model/Contents/WorkflowStep.cs

@@ -12,13 +12,15 @@ namespace Squidex.Domain.Apps.Core.Contents
 {
     public sealed class WorkflowStep
     {
+        public static readonly Dictionary<Status, WorkflowTransition> EmptyTransitions = new Dictionary<Status, WorkflowTransition>();
+
         public IReadOnlyDictionary<Status, WorkflowTransition> Transitions { get; }
 
         public string Color { get; }
 
         public bool NoUpdate { get; }
 
-        public WorkflowStep(IReadOnlyDictionary<Status, WorkflowTransition> transitions, string color, bool noUpdate = false)
+        public WorkflowStep(IReadOnlyDictionary<Status, WorkflowTransition> transitions, string color = null, bool noUpdate = false)
         {
             Guard.NotNull(transitions, nameof(transitions));
 

src/Squidex.Domain.Apps.Core.Model/Contents/Workflows.cs

@@ -8,6 +8,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
+using System.Linq;
 using Squidex.Infrastructure;
 using Squidex.Infrastructure.Collections;
 
@@ -33,5 +34,10 @@ namespace Squidex.Domain.Apps.Core.Contents
 
             return new Workflows(With(Guid.Empty, workflow));
         }
+
+        public Workflow GetFirst()
+        {
+            return Values.FirstOrDefault() ?? Workflow.Default;
+        }
     }
 }

src/Squidex.Domain.Apps.Entities/Apps/AppGrain.cs

@@ -119,6 +119,16 @@ namespace Squidex.Domain.Apps.Entities.Apps
                         return Snapshot;
                     });
 
+                case ConfigureWorkflow configureWorkflow:
+                    return UpdateReturn(configureWorkflow, c =>
+                    {
+                        GuardAppWorkflows.CanConfigure(c);
+
+                        ConfigureWorkflow(c);
+
+                        return Snapshot;
+                    });
+
                 case AddLanguage addLanguage:
                     return UpdateReturn(addLanguage, c =>
                     {
@@ -319,6 +329,11 @@ namespace Squidex.Domain.Apps.Entities.Apps
             RaiseEvent(SimpleMapper.Map(command, new AppClientRevoked()));
         }
 
+        public void ConfigureWorkflow(ConfigureWorkflow command)
+        {
+            RaiseEvent(SimpleMapper.Map(command, new AppWorkflowConfigured()));
+        }
+
         public void AddLanguage(AddLanguage command)
         {
             RaiseEvent(SimpleMapper.Map(command, new AppLanguageAdded()));

src/Squidex.Domain.Apps.Entities/Apps/Commands/ConfigureWorkflow.cs

@@ -0,0 +1,16 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Squidex.Domain.Apps.Core.Contents;
+
+namespace Squidex.Domain.Apps.Entities.Apps.Commands
+{
+    public sealed class ConfigureWorkflow : AppCommand
+    {
+        public Workflow Workflow { get; set; }
+    }
+}

src/Squidex.Domain.Apps.Entities/Apps/Guards/GuardAppWorkflows.cs

@@ -0,0 +1,71 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Domain.Apps.Entities.Apps.Commands;
+using Squidex.Infrastructure;
+
+namespace Squidex.Domain.Apps.Entities.Apps.Guards
+{
+    public static class GuardAppWorkflows
+    {
+        public static void CanConfigure(ConfigureWorkflow command)
+        {
+            Guard.NotNull(command, nameof(command));
+
+            Validate.It(() => "Cannot configure workflow.", e =>
+            {
+                if (command.Workflow == null)
+                {
+                    e(Not.Defined("Workflow"), nameof(command.Workflow));
+                    return;
+                }
+
+                var workflow = command.Workflow;
+
+                if (!workflow.Steps.ContainsKey(workflow.Initial))
+                {
+                    e(Not.Defined("Initial step"), $"{nameof(command.Workflow)}.{nameof(workflow.Initial)}");
+                }
+
+                var stepsPrefix = $"{nameof(command.Workflow)}.{nameof(workflow.Steps)}";
+
+                if (!workflow.Steps.ContainsKey(Status.Published))
+                {
+                    e("Workflow must have a published step.", stepsPrefix);
+                }
+
+                foreach (var step in workflow.Steps)
+                {
+                    var stepPrefix = $"{stepsPrefix}.{step.Key}";
+
+                    if (step.Value == null)
+                    {
+                        e(Not.Defined("Step"), stepPrefix);
+                    }
+                    else
+                    {
+                        foreach (var transition in step.Value.Transitions)
+                        {
+                            var transitionPrefix = $"{stepPrefix}.{nameof(step.Value.Transitions)}.{transition.Key}";
+
+                            if (!workflow.Steps.ContainsKey(transition.Key))
+                            {
+                                e("Transition has an invalid target.", transitionPrefix);
+                            }
+
+                            if (transition.Value == null)
+                            {
+                                e(Not.Defined("Transition"), transitionPrefix);
+                            }
+                        }
+                    }
+                }
+            });
+        }
+    }
+}

src/Squidex.Domain.Apps.Entities/Apps/State/AppState.cs

@@ -96,6 +96,11 @@ namespace Squidex.Domain.Apps.Entities.Apps.State
             Clients = Clients.Revoke(@event.Id);
         }
 
+        protected void On(AppWorkflowConfigured @event)
+        {
+            Workflows = Workflows.Set(@event.Workflow);
+        }
+
         protected void On(AppPatternAdded @event)
         {
             Patterns = Patterns.Add(@event.PatternId, @event.Name, @event.Pattern, @event.Message);

src/Squidex.Domain.Apps.Events/Apps/AppWorkflowConfigured.cs

@@ -0,0 +1,18 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Infrastructure.EventSourcing;
+
+namespace Squidex.Domain.Apps.Events.Apps
+{
+    [EventType(nameof(AppWorkflowConfigured))]
+    public sealed class AppWorkflowConfigured : AppEvent
+    {
+        public Workflow Workflow { get; set; }
+    }
+}

src/Squidex.Shared/Permissions.cs

@@ -81,6 +81,12 @@ namespace Squidex.Shared
         public const string AppPatternsUpdate = "squidex.apps.{app}.patterns.update";
         public const string AppPatternsDelete = "squidex.apps.{app}.patterns.delete";
 
+        public const string AppWorkflows = "squidex.apps.{app}.workflows";
+        public const string AppWorkflowsRead = "squidex.apps.{app}.workflows.read";
+        public const string AppWorkflowsCreate = "squidex.apps.{app}.workflows.create";
+        public const string AppWorkflowsUpdate = "squidex.apps.{app}.workflows.update";
+        public const string AppWorkflowsDelete = "squidex.apps.{app}.workflows.delete";
+
         public const string AppBackups = "squidex.apps.{app}.backups";
         public const string AppBackupsRead = "squidex.apps.{app}.backups.read";
         public const string AppBackupsCreate = "squidex.apps.{app}.backups.create";

src/Squidex/Areas/Api/Controllers/Apps/AppWorkflowsController.cs

@@ -0,0 +1,86 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschränkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Net.Http.Headers;
+using Squidex.Areas.Api.Controllers.Apps.Models;
+using Squidex.Domain.Apps.Entities.Apps;
+using Squidex.Infrastructure.Commands;
+using Squidex.Shared;
+using Squidex.Web;
+
+namespace Squidex.Areas.Api.Controllers.Apps
+{
+    /// <summary>
+    /// Manages and configures apps.
+    /// </summary>
+    [ApiExplorerSettings(GroupName = nameof(Apps))]
+    public sealed class AppWorkflowsController : ApiController
+    {
+        public AppWorkflowsController(ICommandBus commandBus)
+            : base(commandBus)
+        {
+        }
+
+        /// <summary>
+        /// Get app workflow.
+        /// </summary>
+        /// <param name="app">The name of the app.</param>
+        /// <returns>
+        /// 200 => App workflows returned.
+        /// 404 => App not found.
+        /// </returns>
+        [HttpGet]
+        [Route("apps/{app}/workflow/")]
+        [ProducesResponseType(typeof(WorkflowResponseDto), 200)]
+        [ApiPermission(Permissions.AppWorkflowsRead)]
+        [ApiCosts(0)]
+        public IActionResult GetWorkflow(string app)
+        {
+            var response = WorkflowResponseDto.FromApp(App, this);
+
+            Response.Headers[HeaderNames.ETag] = App.Version.ToString();
+
+            return Ok(response);
+        }
+
+        /// <summary>
+        /// Configure workflow of the app.
+        /// </summary>
+        /// <param name="app">The name of the app.</param>
+        /// <param name="request">The new workflow.</param>
+        /// <returns>
+        /// 200 => Workflow configured.
+        /// 400 => Workflow is not valid.
+        /// 404 => App not found.
+        /// </returns>
+        [HttpPut]
+        [Route("apps/{app}/workflow/")]
+        [ProducesResponseType(typeof(WorkflowResponseDto), 200)]
+        [ApiPermission(Permissions.AppWorkflowsUpdate)]
+        [ApiCosts(1)]
+        public async Task<IActionResult> PutWorkflow(string app, [FromBody] UpsertWorkflowDto request)
+        {
+            var command = request.ToCommand();
+
+            var response = await InvokeCommandAsync(command);
+
+            return Ok(response);
+        }
+
+        private async Task<WorkflowResponseDto> InvokeCommandAsync(ICommand command)
+        {
+            var context = await CommandBus.PublishAsync(command);
+
+            var result = context.Result<IAppEntity>();
+            var response = WorkflowResponseDto.FromApp(result, this);
+
+            return response;
+        }
+    }
+}

src/Squidex/Areas/Api/Controllers/Apps/Models/UpsertWorkflowDto.cs

@@ -0,0 +1,45 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Domain.Apps.Entities.Apps.Commands;
+
+namespace Squidex.Areas.Api.Controllers.Apps.Models
+{
+    public sealed class UpsertWorkflowDto
+    {
+        /// <summary>
+        /// The workflow steps.
+        /// </summary>
+        [Required]
+        public Dictionary<Status, WorkflowStepDto> Steps { get; set; }
+
+        /// <summary>
+        /// The initial step.
+        /// </summary>
+        public Status Initial { get; set; }
+
+        public ConfigureWorkflow ToCommand()
+        {
+            var workflow = new Workflow(
+                Steps?.ToDictionary(
+                    x => x.Key,
+                    x => new WorkflowStep(
+                        x.Value?.Transitions.ToDictionary(
+                            y => x.Key,
+                            y => new WorkflowTransition(y.Value.Expression, y.Value.Role)) ?? WorkflowStep.EmptyTransitions,
+                        x.Value.Color,
+                        x.Value.NoUpdate)) ?? Workflow.EmptySteps,
+                Initial);
+
+            return new ConfigureWorkflow { Workflow = workflow };
+        }
+    }
+}

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowDto.cs

@@ -0,0 +1,61 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Infrastructure.Reflection;
+using Squidex.Shared;
+using Squidex.Web;
+
+namespace Squidex.Areas.Api.Controllers.Apps.Models
+{
+    public sealed class WorkflowDto : Resource
+    {
+        /// <summary>
+        /// The workflow steps.
+        /// </summary>
+        [Required]
+        public Dictionary<Status, WorkflowStepDto> Steps { get; set; }
+
+        /// <summary>
+        /// The initial step.
+        /// </summary>
+        public Status Initial { get; set; }
+
+        public static WorkflowDto FromWorkflow(Workflow workflow, ApiController controller, string app)
+        {
+            var result = new WorkflowDto
+            {
+                Steps = workflow.Steps.ToDictionary(
+                    x => x.Key,
+                    x => SimpleMapper.Map(x.Value, new WorkflowStepDto
+                    {
+                        Transitions = x.Value.Transitions.ToDictionary(
+                            y => y.Key,
+                            y => new WorkflowTransitionDto { Expression = y.Value.Expression, Role = y.Value.Role })
+                    })),
+                Initial = workflow.Initial
+            };
+
+            return result.CreateLinks(controller, app);
+        }
+
+        private WorkflowDto CreateLinks(ApiController controller, string app)
+        {
+            var values = new { app };
+
+            if (controller.HasPermission(Permissions.AppWorkflowsUpdate, app))
+            {
+                AddPutLink("update", controller.Url<AppWorkflowsController>(x => nameof(x.PutWorkflow), values));
+            }
+
+            return this;
+        }
+    }
+}

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowResponseDto.cs

@@ -0,0 +1,32 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.ComponentModel.DataAnnotations;
+using Squidex.Domain.Apps.Entities.Apps;
+using Squidex.Web;
+
+namespace Squidex.Areas.Api.Controllers.Apps.Models
+{
+    public sealed class WorkflowResponseDto : Resource
+    {
+        /// <summary>
+        /// The workflow.
+        /// </summary>
+        [Required]
+        public WorkflowDto Workflow { get; set; }
+
+        public static WorkflowResponseDto FromApp(IAppEntity app, ApiController controller)
+        {
+            var result = new WorkflowResponseDto
+            {
+                Workflow = WorkflowDto.FromWorkflow(app.Workflows.GetFirst(), controller, app.Name)
+            };
+
+            return result;
+        }
+    }
+}

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowStepDto.cs

@@ -0,0 +1,32 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using Squidex.Domain.Apps.Core.Contents;
+
+namespace Squidex.Areas.Api.Controllers.Apps.Models
+{
+    public sealed class WorkflowStepDto
+    {
+        /// <summary>
+        /// The transitions.
+        /// </summary>
+        [Required]
+        public Dictionary<Status, WorkflowTransitionDto> Transitions { get; set; }
+
+        /// <summary>
+        /// The optional color.
+        /// </summary>
+        public string Color { get; set; }
+
+        /// <summary>
+        /// Indicates if updates should not be allowed.
+        /// </summary>
+        public bool NoUpdate { get; set; }
+    }
+}

src/Squidex/Areas/Api/Controllers/Apps/Models/WorkflowTransitionDto.cs

@@ -0,0 +1,22 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+namespace Squidex.Areas.Api.Controllers.Apps.Models
+{
+    public sealed class WorkflowTransitionDto
+    {
+        /// <summary>
+        /// The optional expression.
+        /// </summary>
+        public string Expression { get; set; }
+
+        /// <summary>
+        /// The optional restricted role.
+        /// </summary>
+        public string Role { get; set; }
+    }
+}

tests/Squidex.Domain.Apps.Core.Tests/Model/Contents/WorkflowTests.cs

@@ -27,12 +27,10 @@ namespace Squidex.Domain.Apps.Core.Model.Contents
                         StatusColors.Draft),
                 [Status.Archived] =
                     new WorkflowStep(
-                        new Dictionary<Status, WorkflowTransition>(),
-                        StatusColors.Archived, true),
+                        WorkflowStep.EmptyTransitions),
                 [Status.Published] =
                     new WorkflowStep(
-                        new Dictionary<Status, WorkflowTransition>(),
-                        StatusColors.Archived)
+                        WorkflowStep.EmptyTransitions)
             }, Status.Draft);
 
         [Fact]

tests/Squidex.Domain.Apps.Entities.Tests/Apps/AppGrainTests.cs

@@ -10,6 +10,7 @@ using System.Collections.Generic;
 using System.Threading.Tasks;
 using FakeItEasy;
 using Squidex.Domain.Apps.Core.Apps;
+using Squidex.Domain.Apps.Core.Contents;
 using Squidex.Domain.Apps.Entities.Apps.Commands;
 using Squidex.Domain.Apps.Entities.Apps.Services;
 using Squidex.Domain.Apps.Entities.Apps.Services.Implementations;
@@ -256,6 +257,27 @@ namespace Squidex.Domain.Apps.Entities.Apps
                 );
         }
 
+        [Fact]
+        public async Task UpdateClient_should_create_events_and_update_state()
+        {
+            var command = new UpdateClient { Id = clientId, Name = clientNewName, Role = Role.Developer };
+
+            await ExecuteCreateAsync();
+            await ExecuteAttachClientAsync();
+
+            var result = await sut.ExecuteAsync(CreateCommand(command));
+
+            result.ShouldBeEquivalent(sut.Snapshot);
+
+            Assert.Equal(clientNewName, sut.Snapshot.Clients[clientId].Name);
+
+            LastEvents
+                .ShouldHaveSameEvents(
+                    CreateEvent(new AppClientRenamed { Id = clientId, Name = clientNewName }),
+                    CreateEvent(new AppClientUpdated { Id = clientId, Role = Role.Developer })
+                );
+        }
+
         [Fact]
         public async Task RevokeClient_should_create_events_and_update_state()
         {
@@ -277,23 +299,21 @@ namespace Squidex.Domain.Apps.Entities.Apps
         }
 
         [Fact]
-        public async Task UpdateClient_should_create_events_and_update_state()
+        public async Task ConfigureWorkflow_should_create_events_and_update_state()
         {
-            var command = new UpdateClient { Id = clientId, Name = clientNewName, Role = Role.Developer };
+            var command = new ConfigureWorkflow { Workflow = Workflow.Default };
 
             await ExecuteCreateAsync();
-            await ExecuteAttachClientAsync();
 
             var result = await sut.ExecuteAsync(CreateCommand(command));
 
             result.ShouldBeEquivalent(sut.Snapshot);
 
-            Assert.Equal(clientNewName, sut.Snapshot.Clients[clientId].Name);
+            Assert.NotEmpty(sut.Snapshot.Workflows);
 
             LastEvents
                 .ShouldHaveSameEvents(
-                    CreateEvent(new AppClientRenamed { Id = clientId, Name = clientNewName }),
-                    CreateEvent(new AppClientUpdated { Id = clientId, Role = Role.Developer })
+                    CreateEvent(new AppWorkflowConfigured { Workflow = Workflow.Default })
                 );
         }
 

tests/Squidex.Domain.Apps.Entities.Tests/Apps/Guards/GuardAppWorkflowTests.cs

@@ -0,0 +1,134 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using Squidex.Domain.Apps.Core.Contents;
+using Squidex.Domain.Apps.Entities.Apps.Commands;
+using Squidex.Domain.Apps.Entities.TestHelpers;
+using Squidex.Infrastructure;
+using Xunit;
+
+namespace Squidex.Domain.Apps.Entities.Apps.Guards
+{
+    public class GuardAppWorkflowTests
+    {
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_is_not_defined()
+        {
+            var command = new ConfigureWorkflow();
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Workflow is required.", "Workflow"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_has_no_initial_step()
+        {
+            var command = new ConfigureWorkflow
+            {
+                Workflow = new Workflow(
+                    new Dictionary<Status, WorkflowStep>
+                    {
+                        [Status.Published] = new WorkflowStep(WorkflowStep.EmptyTransitions)
+                    },
+                    default)
+            };
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Initial step is required.", "Workflow.Initial"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_does_not_have_published_state()
+        {
+            var command = new ConfigureWorkflow
+            {
+                Workflow = new Workflow(
+                    new Dictionary<Status, WorkflowStep>
+                    {
+                        [Status.Draft] = new WorkflowStep(WorkflowStep.EmptyTransitions)
+                    },
+                    Status.Draft)
+            };
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Workflow must have a published step.", "Workflow.Steps"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_step_is_not_defined()
+        {
+            var command = new ConfigureWorkflow
+            {
+                Workflow = new Workflow(
+                    new Dictionary<Status, WorkflowStep>
+                    {
+                        [Status.Published] = null
+                    },
+                    Status.Published)
+            };
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Step is required.", "Workflow.Steps.Published"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_transition_is_invalid()
+        {
+            var command = new ConfigureWorkflow
+            {
+                Workflow = new Workflow(
+                    new Dictionary<Status, WorkflowStep>
+                    {
+                        [Status.Published] =
+                            new WorkflowStep(
+                                new Dictionary<Status, WorkflowTransition>
+                                {
+                                    [Status.Draft] = new WorkflowTransition()
+                                })
+                    },
+                    Status.Published)
+            };
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Transition has an invalid target.", "Workflow.Steps.Published.Transitions.Draft"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_throw_exception_if_workflow_transition_is_not_defined()
+        {
+            var command = new ConfigureWorkflow
+            {
+                Workflow = new Workflow(
+                    new Dictionary<Status, WorkflowStep>
+                    {
+                        [Status.Draft] =
+                            new WorkflowStep(
+                                WorkflowStep.EmptyTransitions),
+                        [Status.Published] =
+                            new WorkflowStep(
+                                new Dictionary<Status, WorkflowTransition>
+                                {
+                                    [Status.Draft] = null
+                                })
+                    },
+                    Status.Published)
+            };
+
+            ValidationAssert.Throws(() => GuardAppWorkflows.CanConfigure(command),
+                new ValidationError("Transition is required.", "Workflow.Steps.Published.Transitions.Draft"));
+        }
+
+        [Fact]
+        public void CanConfigure_should_not_throw_exception_if_workflow_is_valid()
+        {
+            var command = new ConfigureWorkflow { Workflow = Workflow.Default };
+
+            GuardAppWorkflows.CanConfigure(command);
+        }
+    }
+}