[simonrozsival]

Context: #13278

Android instrumentation already streams individual test results through Microsoft Testing Platform, but an interrupted run may never produce the final results bundle or a usable TRX report. Losing that report must not erase the outcomes already observed, and an absent report must not look like a complete pass.

Retain completed outcomes and unfinished test names in the existing in-memory streaming state before asynchronous result publication. On abnormal termination, print explicitly partial counts, completed outcomes and unfinished context independently of TRX generation. The last observed active test is context, not a proven crash cause; missing bundles and adb failures are not described as proof of a native crash. Preserve normal TRX generation, the legacy device-TRX fallback, publication, retries and gating without adding a wrapper, journal or collector.

The pinned MTP 2.2.1 TRX provider also reported a misleading missing-ITrxReportCapability error for an interrupted active test because its error node omitted TRX class metadata. Carry the streamed class name into that node and use one non-causal unfinished-context message for both the test state and the TRX exception. Completed results retain their outcomes; the interrupted active test is serialized as Failed with an infrastructure-error explanation rather than left in progress. Unfinished streamed tests take this error path even if adb exits successfully or supplies a final bundle, instead of falling into the legacy TRX fallback.

Add thirteen regressions to the existing Xamarin.Android.Tools.AndroidSdk-Tests project, alongside its process and adb tooling tests. Coverage includes real-provider checks of the saved TRX outcomes and exact error text, normal and interrupted runs with unwritable reports, missing bundles, adb failures, process-startup errors, start-only runs and synchronized cancellation after streamed progress. The existing public and official/1ES test jobs already select this project; no separate test project, solution registration or pipeline change remains.

Validation

All commands use the stable .NET host. The existing SDK-discovery suite requires an isolated HOME on this machine: its pre-existing Constructor_SetValuesFromPath test otherwise finds the local android-toolchain/jdk-21 before its fake JDK. The isolated-home baseline passed with 509 tests and 7 skips before moving the unchanged thirteen test cases.

• dotnet build tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj -c Debug -p:AndroidToolsDisableMultiTargeting=false -p:DotNetTargetFrameworkVersion=10.0 -v minimal — passed with 0 errors.
• env HOME=<isolated-test-home> NUGET_PACKAGES=<existing-package-cache> dotnet test tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj --no-build --no-restore -c Debug -p:AndroidToolsDisableMultiTargeting=false -p:DotNetTargetFrameworkVersion=10.0 -v minimal --logger 'trx;LogFileName=pr13313-existing-suite-after.trx' --results-directory <validation-artifacts> — passed: 522 tests, 7 existing environment/platform skips, 0 failures. The saved TRX confirms all thirteen moved streaming cases ran and passed, with no new skips.
• dotnet build tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj -c Release -p:AndroidToolsDisableMultiTargeting=false -p:DotNetTargetFrameworkVersion=10.0 -v minimal — passed with 0 errors.
• dotnet test tests/Xamarin.Android.Tools.AndroidSdk-Tests/Xamarin.Android.Tools.AndroidSdk-Tests.csproj --no-build --no-restore -c Release -p:AndroidToolsDisableMultiTargeting=false -p:DotNetTargetFrameworkVersion=10.0 -v minimal --filter 'FullyQualifiedName~StreamingTests' — passed: 13 tests, 0 skipped.
• make all CONFIGURATION=Release — passed after the move with 0 errors; existing SourceLink warnings remain non-fatal.
• The strengthened real-provider regression failed before the message fix: the saved TRX contained only The test process crashed: Process crashed. instead of the unfinished/non-causal explanation. It passes with the fix and also checks the preceding Passed and interrupted Failed results.
• Both start-only cases failed before their production correction because the TRX fallback threw. They now save a Failed active-test result with the exact non-causal error text, with and without a final bundle. The cancellation test waits for the preceding pass and next active-test update, cancels the still-running invocation, and verifies cancellation propagates while completed outcomes and unfinished context remain in the console summary.
• Local source/XML/YAML checks passed: all test bodies are unchanged by the move, both public and official/1ES callers retain the existing test project selection, and the shared pipeline template matches its pre-PR baseline byte-for-byte. git diff --check passed.

Earlier validation with a session-only two-test CoreCLR fixture on an owned Android 35 arm64 emulator observed the first passing result while the target was still alive. Normal execution produced two passing TRX results; a controlled native abort preserved the preceding pass and produced a failed active-test record; deliberately preventing TRX writing still preserved the partial console output. These device checks precede the final error-message and start-only corrections; the final source was rebuilt and the corrections were verified by the real-provider host regressions.

Azure server-side template expansion and Test Results ingestion have not been independently exercised. If TRX writing itself fails, the fallback is task-log evidence, not structured Azure Tests-tab results. Terminating the host itself can also prevent the final partial summary; this change does not introduce a durable crash-forensics protocol.

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Pull Request
title and
description
should follow the
commit-messages.md workflow documentation, and in particular should include:

• Useful description of why the change is necessary.
• Links to issues fixed
• Unit tests

[Copilot]

🟡 Changes recommended

A start-only adb run exiting with code 0 can throw from the legacy TRX fallback instead of saving a failed infrastructure result for the active test, and cancellation after streamed progress lacks regression coverage.

2 open issues

• Handle start-only adb output as an infrastructure failure · New
• Add cancellation regression coverage for preserving partial results · New

What changed in this PR

This PR improves interrupted on-device test reporting in Microsoft.Android.Run, preserving observed outcomes even when no usable TRX report is produced.

Changes:

• Retains completed outcomes and unfinished test names for explicitly partial console summaries.
• Adds TRX class metadata and non-causal error messages for interrupted active tests.
• Adds ten standalone regression cases, macOS CI selection, and reporting documentation.

File	Description
tests/​Microsoft.Android.Run-Tests/​StreamingTests.cs	Tests streaming, interruption, TRX output, and reporting failures.
tests/​Microsoft.Android.Run-Tests/​Microsoft.Android.Run-Tests.csproj	Defines the standalone adapter test project.
src/​Microsoft.Android.Run/​AndroidTestAdapter.cs	Preserves partial observations and improves interrupted-test reporting.
Microsoft.Android.slnx	Adds the test project to the solution.
Documentation/​building/​windows/​instructions.md	Documents streamed results and partial summaries.
Documentation/​building/​unix/​instructions.md	Documents streamed results and partial summaries.
build-tools/​automation/​yaml-templates/​stage-xamarin-android-tools-tests.yaml	Selects the suite in the shared macOS standalone-test step.
.github/​skills/​tests/​references/​test-catalog.md	Lists the standalone suite and its command.

_{Review effort: Balanced}