Add artifact merge engines and Kind metadata flow (RFC 018 phase 1)

src/Platform/Microsoft.Testing.Extensions.CtrfReport/CtrfReportGenerator.cs

@@ -24,6 +24,8 @@ public CtrfReportGenerator(IServiceProvider serviceProvider)
 
     protected override string ArtifactDisplayName => ExtensionResources.CtrfReportArtifactDisplayName;
 
+    protected override string? ArtifactKind => "microsoft.testing.ctrf";
+
     protected override string ArtifactDescription => ExtensionResources.CtrfReportArtifactDescription;
 
     protected override string GetGenerationLogMessage(int testResultCount)

src/Platform/Microsoft.Testing.Extensions.CtrfReport/CtrfReportMerger.cs

@@ -0,0 +1,220 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+using Microsoft.Testing.Platform;
+
+namespace Microsoft.Testing.Extensions.CtrfReport;
+
+/// <summary>
+/// Merges several already-produced CTRF JSON reports into a single CTRF document.
+/// </summary>
+/// <remarks>
+/// This is a pure, invocation-agnostic JSON-level merge (no I/O, no clock) that mirrors the
+/// TRX and JUnit mergers, demonstrating that the same post-processing shape fits a JSON format:
+/// <list type="bullet">
+///   <item><description><c>results.tests[]</c> arrays are concatenated as-is.</description></item>
+///   <item><description><c>results.summary</c> counters are re-derived by counting the merged <c>tests[]</c> (so <c>summary.tests</c> always matches the array length); <c>start</c>/<c>stop</c> use the earliest/latest across inputs, <c>duration</c> is the resulting span.</description></item>
+///   <item><description><c>reportFormat</c>, <c>specVersion</c>, <c>tool</c> and <c>environment</c> are taken from the first report; <c>reportId</c> is freshly generated.</description></item>
+/// </list>
+/// </remarks>
+internal static class CtrfReportMerger
+{
+    internal static string Merge(IReadOnlyList<string> inputReports)
+    {
+        if (inputReports is null)
+        {
+            throw new ArgumentNullException(nameof(inputReports));
+        }
+
+        if (inputReports.Count == 0)
+        {
+            throw new ArgumentException("At least one CTRF report is required to merge.", nameof(inputReports));
+        }
+
+        JsonObject? first = null;
+        var mergedTests = new JsonArray();
+
+        long? earliestStart = null;
+        long? latestStop = null;
+
+        foreach (string reportJson in inputReports)
+        {
+            if (JsonNode.Parse(reportJson) is not JsonObject root)
+            {
+                continue;
+            }
+
+            first ??= root;
+
+            JsonNode? results = root["results"];
+            if (results?["tests"] is JsonArray testArray)
+            {
+                foreach (JsonNode? test in testArray)
+                {
+                    mergedTests.Add(test?.DeepClone());
+                }
+            }
+
+            JsonNode? summary = results?["summary"];
+            if (summary is not null)
+            {
+                if (TryReadLong(summary, "start", out long start) && (earliestStart is null || start < earliestStart))
+                {
+                    earliestStart = start;
+                }
+
+                if (TryReadLong(summary, "stop", out long stop) && (latestStop is null || stop > latestStop))
+                {
+                    latestStop = stop;
+                }
+            }
+        }
+
+        if (first is null)
+        {
+            throw new ArgumentException("None of the provided inputs were valid CTRF reports.", nameof(inputReports));
+        }
+
+        long startMs = earliestStart ?? 0;
+        long stopMs = latestStop ?? startMs;
+
+        // Counters are derived from the merged tests[] rather than trusting each input's summary, so
+        // summary.tests always equals the array length even when an input omitted or under-reported
+        // its summary.
+        long passed = 0, failed = 0, skipped = 0, pending = 0, other = 0, flaky = 0;
+        foreach (JsonNode? test in mergedTests)
+        {
+            if (test is null)
+            {
+                continue;
+            }
+
+            switch ((string?)test["status"])
+            {
+                case "passed": passed++; break;
+                case "failed": failed++; break;
+                case "skipped": skipped++; break;
+                case "pending": pending++; break;
+                default: other++; break;
+            }
+
+            if (test["flaky"] is JsonValue flakyValue && flakyValue.TryGetValue(out bool isFlaky) && isFlaky)
+            {
+                flaky++;
+            }
+        }
+
+        var summaryObject = new JsonObject
+        {
+            ["tests"] = mergedTests.Count,
+            ["passed"] = passed,
+            ["failed"] = failed,
+            ["skipped"] = skipped,
+            ["pending"] = pending,
+            ["other"] = other,
+            ["flaky"] = flaky,
+            ["start"] = startMs,
+            ["stop"] = stopMs,
+            ["duration"] = Math.Max(0, stopMs - startMs),
+        };
+
+        var resultsObject = new JsonObject();
+        if (first["results"]?["tool"] is JsonNode tool)
+        {
+            resultsObject["tool"] = tool.DeepClone();
+        }
+
+        resultsObject["summary"] = summaryObject;
+
+        if (first["results"]?["environment"] is JsonNode environment)
+        {
+            resultsObject["environment"] = environment.DeepClone();
+        }
+
+        resultsObject["tests"] = mergedTests;
+
+        var merged = new JsonObject
+        {
+            ["reportFormat"] = first["reportFormat"]?.DeepClone() ?? "CTRF",
+            ["specVersion"] = first["specVersion"]?.DeepClone() ?? "0.0.0",
+            ["reportId"] = Guid.NewGuid().ToString("D"),
+            ["timestamp"] = DateTimeOffset.FromUnixTimeMilliseconds(stopMs).ToString("O", CultureInfo.InvariantCulture),
+            ["results"] = resultsObject,
+        };
+
+        if (first["generatedBy"] is JsonNode generatedBy)
+        {
+            merged["generatedBy"] = generatedBy.DeepClone();
+        }
+
+        return merged.ToJsonString(new JsonSerializerOptions { WriteIndented = true });
+    }
+
+    internal static async Task MergeToFileAsync(
+        IReadOnlyList<string> inputPaths,
+        string outputPath,
+        CancellationToken cancellationToken)
+    {
+        if (inputPaths is null)
+        {
+            throw new ArgumentNullException(nameof(inputPaths));
+        }
+
+        if (outputPath is null)
+        {
+            throw new ArgumentNullException(nameof(outputPath));
+        }
+
+        var reports = new List<string>(inputPaths.Count);
+        foreach (string inputPath in inputPaths)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+#if NETCOREAPP
+            reports.Add(await File.ReadAllTextAsync(inputPath, cancellationToken).ConfigureAwait(false));
+#else
+            reports.Add(File.ReadAllText(inputPath));
+#endif
+        }
+
+        string merged = Merge(reports);
+
+        string? outputDirectory = Path.GetDirectoryName(outputPath);
+        if (!RoslynString.IsNullOrEmpty(outputDirectory))
+        {
+            Directory.CreateDirectory(outputDirectory);
+        }
+
+#if NETCOREAPP
+        await File.WriteAllTextAsync(outputPath, merged, cancellationToken).ConfigureAwait(false);
+#else
+        File.WriteAllText(outputPath, merged);
+        await Task.CompletedTask.ConfigureAwait(false);
+#endif
+    }
+
+    private static bool TryReadLong(JsonNode summary, string propertyName, out long value)
+    {
+        value = 0;
+        if (summary[propertyName] is not JsonValue jsonValue)
+        {
+            return false;
+        }
+
+        if (jsonValue.TryGetValue(out long longValue))
+        {
+            value = longValue;
+            return true;
+        }
+
+        if (jsonValue.TryGetValue(out double doubleValue))
+        {
+            value = (long)doubleValue;
+            return true;
+        }
+
+        return false;
+    }
+}

src/Platform/Microsoft.Testing.Extensions.CtrfReport/InternalAPI/InternalAPI.Unshipped.txt

@@ -1 +1,5 @@
 #nullable enable
+virtual Microsoft.Testing.Extensions.ReportGeneratorBase<TGenerator, TCapturedTestResult>.ArtifactKind.get -> string?
+Microsoft.Testing.Extensions.CtrfReport.CtrfReportMerger
+static Microsoft.Testing.Extensions.CtrfReport.CtrfReportMerger.Merge(System.Collections.Generic.IReadOnlyList<string!>! inputReports) -> string!
+static Microsoft.Testing.Extensions.CtrfReport.CtrfReportMerger.MergeToFileAsync(System.Collections.Generic.IReadOnlyList<string!>! inputPaths, string! outputPath, System.Threading.CancellationToken cancellationToken) -> System.Threading.Tasks.Task!

src/Platform/Microsoft.Testing.Extensions.HangDump/InternalAPI/InternalAPI.Unshipped.txt

@@ -1,3 +1,4 @@
 #nullable enable
+const Microsoft.Testing.Platform.IPC.FileArtifactMessageFieldsId.Kind = 7 -> ushort
 static Microsoft.Testing.Platform.IPC.Serializers.BaseSerializer.ReadFields(System.IO.Stream! stream, System.Func<ushort, int, bool>! tryReadField) -> void
 static Microsoft.Testing.Platform.IPC.Serializers.BaseSerializer.WriteListPayload<T>(System.IO.Stream! stream, ushort fieldId, T[]? list, System.Action<System.IO.Stream!, T>! writeItem) -> void

src/Platform/Microsoft.Testing.Extensions.HtmlReport/HtmlReportGenerator.cs

@@ -24,6 +24,8 @@ public HtmlReportGenerator(IServiceProvider serviceProvider)
 
     protected override string ArtifactDisplayName => ExtensionResources.HtmlReportArtifactDisplayName;
 
+    protected override string? ArtifactKind => "microsoft.testing.html";
+
     protected override string ArtifactDescription => ExtensionResources.HtmlReportArtifactDescription;
 
     protected override string GetGenerationLogMessage(int testResultCount)

src/Platform/Microsoft.Testing.Extensions.HtmlReport/InternalAPI/InternalAPI.Unshipped.txt

@@ -1 +1,2 @@
 #nullable enable
+virtual Microsoft.Testing.Extensions.ReportGeneratorBase<TGenerator, TCapturedTestResult>.ArtifactKind.get -> string?

src/Platform/Microsoft.Testing.Extensions.JUnitReport/InternalAPI/InternalAPI.Unshipped.txt

@@ -1 +1,5 @@
 #nullable enable
+virtual Microsoft.Testing.Extensions.ReportGeneratorBase<TGenerator, TCapturedTestResult>.ArtifactKind.get -> string?
+Microsoft.Testing.Extensions.JUnitReport.JUnitReportMerger
+static Microsoft.Testing.Extensions.JUnitReport.JUnitReportMerger.Merge(System.Collections.Generic.IReadOnlyList<System.Xml.Linq.XDocument!>! inputReports, string! reportName) -> System.Xml.Linq.XDocument!
+static Microsoft.Testing.Extensions.JUnitReport.JUnitReportMerger.MergeToFileAsync(System.Collections.Generic.IReadOnlyList<string!>! inputPaths, string! outputPath, string! reportName, System.Threading.CancellationToken cancellationToken) -> System.Threading.Tasks.Task!

src/Platform/Microsoft.Testing.Extensions.JUnitReport/JUnitReportGenerator.cs

@@ -33,6 +33,8 @@ public JUnitReportGenerator(IServiceProvider serviceProvider)
 
     protected override string ArtifactDisplayName => ExtensionResources.JUnitReportArtifactDisplayName;
 
+    protected override string? ArtifactKind => "microsoft.testing.junit";
+
     protected override string ArtifactDescription => ExtensionResources.JUnitReportArtifactDescription;
 
     protected override string GetGenerationLogMessage(int testResultCount)