Testing

Three suites, all headless: no GPU and no display. They create an ImGui context with a font atlas and drive real frames.

./src/core/tests/run_tests.sh                      # 12 tests
./undoApps/undoApp.Editor/tests/run_tests.sh       # 26 tests
./undoApps/undoApp.Terminal/tests/run_tests.sh     # 2 tests
 
# a subset, by name
./undoApps/undoApp.Editor/tests/run_tests.sh completion
./src/core/tests/run_tests.sh recents

The Editor and Terminal suites need the project built first: they link against libundoStudioCore.so, libimgui.a and libimplot.a.

What each one covers

Suite
core	the state files, the recent projects and files lists, the open-file request between the core and an undoApp, the popup dismissal, and the shipped layout
Editor	the ST document, the completion lists and their placement, the semantic tokens, the diagnostics end to end, the tab bar, the dirty state, renames, the output filters, and the JSON routing
Terminal	the shell under a pty, and its tab bar

The Editor suite links each test against one archive of the sources the tests share and reaches into the editor's internals with a #define private public. Two things worth knowing before adding a test:

• a new plugin source file has to be added to PLUGIN_SRC in undoApps/undoApp.Editor/tests/Makefile, or every test that needs it fails to link — and the failure looks like a missing symbol rather than a missing entry in a list
• a test that drives ImGui must not be listed in PURE, the set that skips the ImGui link line, or it fails at link time pointing at the archive rather than at the list

Driving the GUI without a window

A panel body draws contents only, because ImGuiManager owns the window. So a test that draws one has to Begin the panel itself:

• tests/st_editor_frame.hpp is that Begin for the ST document
• the Output, Workspace and JSON panels are Begin/End-ed by hand

A body called bare trips ImGui's own "Calling End() too many times" assert, which points at the assert rather than at the Begin that is missing.

The four things that are not obvious

• a widget is found in the draw list, not by name. ImGui keeps no rect per item across frames, and no API asks for the rectangle of an item it is not drawing. The draw list has to be read during the frame that filled it: after EndFrame the window is gone. And a widget found by its fill colour is not found while it is hovered, so the mouse is parked away before measuring
• a click is three events and three frames. Position, press and release, each its own frame, with the panel redrawn in every one of them: ImGui hit-tests each item as it is submitted, so a frame that queues a mouse event and draws nothing has nothing to hit. A checkbox toggles on the release
• **ContentSize is one frame behind.** A window publishes the size its content had during the previous frame. Read straight after changing a filter, the two directions measure equal, which reads as "the filter does nothing"
• typing needs a click first. The editor raises "the text changed" only for input it handled while being drawn, so a test cannot type with SetText — a load uses that too. It has to click into the editor and then feed io.AddInputCharacter, and the click is also the only thing that focuses the editor's child window

What the tests are for

Each one has found a real bug: a fuzzy match stealing the member completion, 1841 cells in 1920 painted the wrong colour, a key written above its own section header, a recent-files row that rendered in the right order in the right place with the right name on it and could not be picked because its ID belonged to another row.