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Document terminal progress console output limitation #54825

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Evangelink merged 2 commits into from
Jul 21, 2026
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Document terminal progress console output limitation #54825

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Document direct console output limitation with ANSI progress redraw
Evangelink Jul 17, 2026
cacb577
Potential fix for pull request finding
Evangelink Jul 21, 2026
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10 changes: 9 additions & 1 deletion docs/core/testing/microsoft-testing-platform-terminal-output.md
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Expand Up @@ -3,7 +3,7 @@ title: Microsoft.Testing.Platform (MTP) terminal output
description: Learn about the built-in terminal test reporter in MTP, including output modes, ANSI support, and progress indicators.
author: evangelink
ms.author: amauryleve
ms.date: 06/16/2026
ms.date: 07/17/2026
ai-usage: ai-assisted
---

Expand Down Expand Up @@ -41,6 +41,14 @@ The progress bar is written based on the selected mode:
- ANSI, the progress bar is animated, sticking to the bottom of the screen and is refreshed every 500ms. The progress bar hides once test execution is done.
- non-ANSI, the progress bar is written to screen as is every 3 seconds. The progress remains in the output.

### Direct console output and progress redraw

To animate the progress bar, the ANSI progress renderer takes control of the terminal cursor and repeatedly redraws the bottom of the screen. Any text that's written directly to `stdout` or `stderr` outside the test framework's capture path can be overwritten or removed during this redraw. For example, a `Console.WriteLine` call from assembly-level or session-level lifecycle code (such as a `Before(Assembly)` or `Before(TestSession)` hook), or from an extension, might flash briefly and then disappear when the progress bar refreshes.

This behavior is distinct from *captured* per-test standard output and standard error. Output that a test writes while it runs is captured by the framework and shown according to `--show-stdout` and `--show-stderr`, so the progress bar doesn't overwrite it.

If your code must write directly to the console and you need that output to remain visible, disable progress (`--progress off` in MTP 2.3.0+, or `--no-progress` in earlier versions). Alternatively, disable ANSI (`--ansi off` in MTP 2.3.0+, or `--no-ansi` in earlier versions) to use the non-ANSI progress output, which appends new lines instead of redrawing in place and doesn't overwrite prior direct output.

## Options

| Option | MTP version | Description |
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