Add interaction tests (#15251)

Content.IntegrationTests/Tests/Weldable/WeldableTests.cs

@@ -0,0 +1,28 @@
+using System.Threading.Tasks;
+using Content.IntegrationTests.Tests.Interaction;
+using Content.Server.Tools.Components;
+using NUnit.Framework;
+
+namespace Content.IntegrationTests.Tests.Weldable;
+
+/// <summary>
+///  Simple test to check that using a welder on a locker will weld it shut.
+/// </summary>
+public sealed class WeldableTests : InteractionTest
+{
+    public const string Locker = "LockerFreezer";
+
+    [Test]
+    public async Task WeldLocker()
+    {
+        await SpawnTarget(Locker);
+        var comp = Comp<WeldableComponent>();
+
+        Assert.That(comp.Weldable, Is.True);
+        Assert.That(comp.IsWelded, Is.False);
+
+        await Interact(Weld);
+        Assert.That(comp.IsWelded, Is.True);
+        AssertPrototype(Locker); // Prototype did not change.
+    }
+}