Can't run a runnable test item with a single non-runnable child

[firelizzard18]

Type: Bug

Using the testing API:

1. Create run profile with tag id: runnable.
2. Create test item A including tag id: runnable and add it to the root or some other collection.
3. Create test item B without the runnable tag and add it as a child to A.
4. Attempt to run test item A.

VS Code version: Code 1.93.1 (38c31bc, 2024-09-11T17:20:05.685Z)
OS version: Linux x64 6.6.21-gentoo
Modes:

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-10850K CPU @ 3.60GHz (20 x 4799)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off webnn: disabled_off
Load (avg)	1, 1, 1
Memory (System)	62.61GB (50.72GB free)
Process Argv	--ozone-platform-hint=auto --enable-wayland-ime --crash-reporter-id 217c2155-7214-48e7-83e7-a2317fced1b9
Screen Reader	no
VM	0%
DESKTOP_SESSION	plasma
XDG_CURRENT_DESKTOP	KDE
XDG_SESSION_DESKTOP	KDE
XDG_SESSION_TYPE	wayland

Extensions (77)

Extension	Author (truncated)	Version
language-x86-64-assembly	13x	3.1.4
golangwithdidi	ald	0.0.1
Bookmarks	ale	13.5.0
chronicler	arc	0.1.16
quitcontrol-vscode	art	4.0.0
unique-lines	bib	1.0.0
markdown-mermaid	bie	1.25.0
esbuild-problem-matchers	con	0.0.3
systemd-unit-file	coo	1.0.6
vscode-eslint	dba	3.0.10
xml	Dot	2.5.1
udev-rules	dpk	1.0.1
gitlens	eam	15.5.1
permute-lines	ear	1.1.0
EditorConfig	Edi	0.16.4
prettier-vscode	esb	11.0.0
go-notebook-kernel	eth	0.2.0
go-playbooks	eth	0.0.3
simple-notebook-renderers	eth	0.1.1
vscode-firefox-debug	fir	2.9.10
copilot	Git	1.232.0
copilot-chat	Git	0.20.3
remotehub	Git	0.64.0
gitlab-workflow	Git	5.12.0
gitpod-desktop	git	0.0.174
go	gol	0.42.1
vscode-graphql	Gra	0.12.0
vscode-graphql-execution	Gra	0.3.0
vscode-graphql-syntax	Gra	1.3.6
vscode-test-explorer	hbe	2.21.1
vscode-ansi	ili	1.1.7
vscode-go-template	jin	0.2.1
solidity	Jua	0.0.176
vscode-clangd	llv	0.1.29
bash-ide-vscode	mad	1.42.0
rainbow-csv	mec	3.12.0
template-string-converter	meg	0.6.1
graphql	mqu	0.1.2
vscode-docker	ms-	1.29.1
csharp	ms-	2.45.25
vscode-dotnet-runtime	ms-	2.1.5
debugpy	ms-	2024.10.0
python	ms-	2024.14.1
vscode-pylance	ms-	2024.9.1
jupyter	ms-	2024.8.1
jupyter-keymap	ms-	1.1.2
jupyter-renderers	ms-	1.0.19
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
remote-containers	ms-	0.384.0
remote-ssh	ms-	0.114.3
remote-ssh-edit	ms-	0.86.0
cmake-tools	ms-	1.19.52
hexeditor	ms-	1.10.0
remote-explorer	ms-	0.4.3
remote-repositories	ms-	0.42.0
test-adapter-converter	ms-	0.1.9
vscode-markdown-notebook	ms-	0.0.26
vscode-serial-monitor	ms-	0.13.1
wasm-dwarf-debugging	ms-	1.0.1
vsliveshare	ms-	1.0.5940
vsliveshare-pack	ms-	0.4.0
linux-desktop-file	nic	0.0.21
vscode-jest	Ort	6.2.5
material-icon-theme	PKi	5.10.0
vscode-xml	red	0.27.1
vscode-yaml	red	1.15.0
bash-beautify	sha	0.1.1
shader	sle	1.1.5
rewrap	stk	1.16.3
code-spell-checker	str	3.0.1
even-better-toml	tam	0.19.2
vscode-tinygo	tin	0.5.0
cmake	twx	0.0.17
vscode-mdx	uni	1.8.11
spice	xua	0.1.0
vscode-proto3	zxh	0.5.5

[firelizzard18]

I verified this in the extension host, and by debugging vscode with vscode and installing my extension as a VSIX into the running-in-a-debugger vscode. I generated the report from the host/top vscode which is why it shows all those extensions.

The behavior is coming from this function:

vscode/src/vs/workbench/contrib/testing/browser/testingExplorerView.ts

Lines 166 to 201 in 6b924c5

	const attempt = (element: TestExplorerTreeElement, alreadyIncluded: boolean) => {
	// sanity check hasElement since updates are debounced and they may exist
	// but not be rendered yet
	if (!(element instanceof TestItemTreeElement) || !this.viewModel.tree.hasElement(element)) {
	return;
	}
	// If the current node is not visible or runnable in the current profile, it's excluded
	const inTree = this.viewModel.tree.getNode(element);
	if (!inTree.visible) {
	if (alreadyIncluded) { exclude.push(element.test); }
	return;
	}
	// If it's not already included but most of its children are, then add it
	// if it can be run under the current profile (when specified)
	if (
	// If it's not already included...
	!alreadyIncluded
	// And it can be run using the current profile (if any)
	&& (!profile || canUseProfileWithTest(profile, element.test))
	// And either it's a leaf node or most children are included, the include it.
	&& (inTree.children.length === 0 || inTree.visibleChildrenCount * 2 >= inTree.children.length)
	// And not if we're only showing a single of its children, since it
	// probably fans out later. (Worse case we'll directly include its single child)
	&& inTree.visibleChildrenCount !== 1
	) {
	include.add(element.test);
	alreadyIncluded = true;
	}
	// Recurse ✨
	for (const child of element.children) {
	attempt(child, alreadyIncluded);
	}
	};

I'm not going to pretend to understand why inTree.visibleChildrenCount !== 1 is there but the end result is that test item A does not get added to the include set. This is tolerable when test item B is runnable, because at the very least I can explicitly transform a request to run B into a request to run A, but if B is not runnable it just does nothing because the include set ends up empty and it never even calls the extension's run profile. Personally I don't like this behavior - if the user clicks run on test item A, then vscode should tell the extension "the user wishes to run test item A". But instead, the user clicks on A and vscode says "the user wishes to run B", which is surprising in a bad way to me. But ultimately, it wouldn't break anything for me except for the fact that this still happens when B is not runnable.

CC @connor4312