Add project files.

test/integration/Elsa.Workflows.IntegrationTests/Activities/WriteLine/WriteLineTests.cs

@@ -0,0 +1,30 @@
+using Elsa.Testing.Shared;
+using Elsa.Workflows.Activities;
+using Microsoft.Extensions.DependencyInjection;
+using Xunit.Abstractions;
+
+namespace Elsa.Workflows.IntegrationTests.Activities;
+
+public class WriteLineTests
+{
+    private readonly IWorkflowRunner _workflowRunner;
+    private readonly CapturingTextWriter _capturingTextWriter = new();
+    private readonly IServiceProvider _services;
+
+    public WriteLineTests(ITestOutputHelper testOutputHelper)
+    {
+        _services = new TestApplicationBuilder(testOutputHelper).WithCapturingTextWriter(_capturingTextWriter).Build();
+        _workflowRunner = _services.GetRequiredService<IWorkflowRunner>();
+    }
+
+    [Fact(DisplayName = "Run a simple workflow")]
+    public async Task Test1()
+    {
+        var expectedOutput = "Hello World!";
+        var workflow = Workflow.FromActivity(new WriteLine(expectedOutput));
+        await _services.PopulateRegistriesAsync();
+        await _workflowRunner.RunAsync(workflow);
+        var line = _capturingTextWriter.Lines.FirstOrDefault();
+        Assert.Equal(expectedOutput, line);
+    }
+}