Add project files.

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

@@ -0,0 +1,25 @@
+using Elsa.Testing.Shared;
+using Elsa.Workflows.Activities;
+using Xunit.Abstractions;
+
+namespace Elsa.Activities.IntegrationTests;
+
+public class WriteLineTests
+{
+    private readonly CapturingTextWriter _capturingTextWriter = new();
+    private readonly IServiceProvider _serviceProvider;
+
+    public WriteLineTests(ITestOutputHelper testOutputHelper)
+    {
+        _serviceProvider = new TestApplicationBuilder(testOutputHelper).WithCapturingTextWriter(_capturingTextWriter).Build();
+    }
+    
+    [Fact(DisplayName = "WriteLine prints the expected line to the console.")]
+    public async Task Test1()
+    {
+        const string expectedLine = "Hello world!";
+        var writeLine = new WriteLine(expectedLine);
+        await _serviceProvider.RunActivityAsync(writeLine);
+        Assert.Equal(expectedLine, _capturingTextWriter.Lines.Single());
+    }
+}