[windows] Make keyboard layout tests hermetic#189573
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The keyboard tests are authored against the US and US-International layouts, but the test harness resolved characters through MapVirtualKey, which consults the keyboard layout installed on the machine running the tests. On a non-US host the same virtual key produces a different character, so layout-sensitive tests such as DeadKeyTwiceThenLetter fail (VK_OEM_3 is the grave accent on US but an umlaut on German). Add a hermetic US layout table (LayoutUsStandard) and route the default and French test layouts through it, so the character mapping no longer depends on the host configuration.
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This was referenced Jul 16, 2026
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The Windows keyboard tests in
keyboard_unittests.ccare authored against the US and US-International layouts, but the test harness resolves a virtual key to a character throughMapVirtualKey(vk, MAPVK_VK_TO_CHAR), which consults the keyboard layout installed on the machine running the tests. On a host configured with a non-US layout the same virtual key produces a different character, so layout-sensitive tests fail. For example,KeyboardTest.DeadKeyTwiceThenLetterpressesVK_OEM_3, which is the grave accent on a US layout but an umlaut on a German layout, so the test expects`and receivesö.This makes the character mapping hermetic. A new
LayoutUsStandardreturns the valueMapVirtualKey(vk, MAPVK_VK_TO_CHAR)produces on a US layout for the keys the tests exercise (digits, letters, the OEM punctuation keys, and the control keys the tests use), and the default and French test layouts route theirMAPVK_VK_TO_CHARlookups through it. Non-character virtual keys keep returning0, matching the platform. The tests no longer depend on the layout installed on the machine running them.Verified on a machine configured with the German (de-DE) layout: before this change
KeyboardTest.DeadKeyTwiceThenLetterfails; after it, all 36KeyboardTestcases pass. The suite continues to pass on US layouts.Fixes #189566
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