Adds everyone-test-a-file test

Tests/CodexTests/ScalabilityTests/ScalabilityTests.cs

@@ -1,5 +1,6 @@
 using CodexPlugin;
 using DistTestCore;
+using FileUtils;
 using NUnit.Framework;
 using Utils;
 
@@ -11,6 +12,10 @@ public class ScalabilityTests : CodexDistTest
     private const string PatchedImage = "codexstorage/nim-codex:sha-9aeac06-dist-tests";
     private const string MasterImage = "codexstorage/nim-codex:sha-5380912-dist-tests";
 
+    /// <summary>
+    /// We upload a file to node A, then download it with B.
+    /// Then we stop node A, and download again with node C.
+    /// </summary>
     [Test]
     [Combinatorial]
     [UseLongTimeouts]
@@ -48,4 +53,76 @@ public class ScalabilityTests : CodexDistTest
 
         downloadedFile!.AssertIsEqual(testFile);
     }
+
+    /// <summary>
+    /// We upload a file to each node, to put a more wide-spread load on the network.
+    /// Then we run the same test as ShouldMaintainFileInNetwork.
+    /// </summary>
+    [Test]
+    [Combinatorial]
+    [UseLongTimeouts]
+    [DontDownloadLogs]
+    public void EveryoneGetsAFile(
+        [Values(10, 40, 80, 100)] int numberOfNodes,
+        [Values(100, 1000)] int fileSizeInMb,
+        [Values(true, false)] bool usePatchedImage
+    )
+    {
+        CodexContainerRecipe.DockerImageOverride = usePatchedImage ? PatchedImage : MasterImage;
+
+        var logLevel = CodexLogLevel.Info;
+
+        var bootstrap = AddCodex(s => s.WithLogLevel(logLevel));
+        var nodes = AddCodex(numberOfNodes - 1, s => s
+            .WithBootstrapNode(bootstrap)
+            .WithLogLevel(logLevel)
+            .WithStorageQuota((fileSizeInMb + 50).MB())
+        ).ToList();
+
+        var pairTasks = nodes.Select(n =>
+        {
+            return Task.Run(() =>
+            {
+                var file = GenerateTestFile(fileSizeInMb.MB());
+                var cid = n.UploadFile(file);
+                return new NodeFilePair(n, file, cid);
+            });
+        });
+
+        var pairs = pairTasks.Select(t => Time.Wait(t)).ToList();
+
+        RunDoubleDownloadTest(
+            pairs.PickOneRandom(),
+            pairs.PickOneRandom(),
+            pairs.PickOneRandom()
+        );
+    }
+
+    private void RunDoubleDownloadTest(NodeFilePair source, NodeFilePair dl1, NodeFilePair dl2)
+    {
+        var expectedFile = source.File;
+        var cid = source.Cid;
+
+        var file1 = dl1.Node.DownloadContent(cid);
+        file1!.AssertIsEqual(expectedFile);
+
+        source.Node.Stop(true);
+
+        var file2 = dl2.Node.DownloadContent(cid);
+        file2!.AssertIsEqual(expectedFile);
+    }
+
+    public class NodeFilePair
+    {
+        public NodeFilePair(ICodexNode node, TrackedFile file, ContentId cid)
+        {
+            Node = node;
+            File = file;
+            Cid = cid;
+        }
+
+        public ICodexNode Node { get; }
+        public TrackedFile File { get; }
+        public ContentId Cid { get; }
+    }
 }