Terminal

Changing the terminalCopy Anchor Link

These act on the terminal around your program, rather than typing into it.

ResizeCopy Anchor Link

Resize resizes the terminal, and your program gets a tea.WindowSizeMsg. Wait for the redraw, then check the result:

h.Wait("Sencha").
	Resize(48, 16).
	WaitSettle().
	Assert("q quit")

For a command on an exec harness, its pseudo-terminal is resized too, so it gets a real SIGWINCH.

Dimensions, Width, Height, and Bounds return the terminal's size in cells.

FocusCopy Anchor Link

Focus and Blur send a focus event, if your program enabled focus reporting. IsFocused returns the last known state. Terminals start focused.

h.Blur().Wait("paused").Focus().WaitNot("paused")

ScrollingCopy Anchor Link

ScrollUp moves the viewport toward older scrollback, without telling the program, so View, snapshots, and recordings show the older rows. The viewport stays put as the program writes more, until ScrollDown, ScrollToBottom, or input.

h.ScrollUp(10)
h.ScrollToTop()
h.ScrollToBottom()
h.SetScrollbackSize(5000)
h.ClearScrollback()

The alternate screen has no scrollback, so these are for programs that print to the normal screen.

ColorsCopy Anchor Link

These set what your program finds when it asks the terminal about colors, so you can test a program that adapts to light and dark terminals:

h := steep.NewHarness(t, newModel())
h.SetBgColor(lipgloss.Color("#ffffff"))

A color your program sets itself, with OSC 10, 11, or 12, comes first, until it resets it.

ClipboardCopy Anchor Link

SetClipboard sets what the program reads with OSC 52. Clipboard returns what it last wrote, as below.

h.SetClipboard("copied text")

Color supportCopy Anchor Link

WithColor sets what the terminal advertises when the program starts:

Reading what the program told itCopy Anchor Link

A terminal holds more than a screen. Your program can set a title, move and hide the cursor, write to the clipboard, and report progress. The harness reads all of that from the emulator.

h.Wait("Sencha").Key("enter").Wait("█")

if p := h.Progress(); p.Percent == 0 {
	t.Errorf("progress = %+v", p)
}

h.Wait("Sencha is ready")

if got := h.Title(); got != "tea shop" {
	t.Errorf("title = %q", got)
}
if !h.IsAltScreen() {
	t.Error("should be on the alternate screen")
}

// tea.Raw runs as a command of its own, so the notification can land after
// the frame that announces it, and Wait can't see it arrive, since it doesn't
// change the screen.
deadline := time.Now().Add(5 * time.Second)
for len(h.Notifications()) == 0 && time.Now().Before(deadline) {
	time.Sleep(5 * time.Millisecond)
}
if n := h.Notifications(); len(n) != 1 || n[0].Body != "Sencha is ready" {
	t.Errorf("notifications = %+v", n)
}

ScreenCopy Anchor Link

CursorCopy Anchor Link

What the program reportedCopy Anchor Link

Colors and focusCopy Anchor Link

FgColor, BgColor, and CursorColor return the emulator's current colors, and IsFocused its focus. See Colors to set them.

ImagesCopy Anchor Link

Image draws the screen with the Render options of the recording profile. It reuses the image on the next call, so copy it if you need to keep it, or use ImageInto, which draws into an image you own. Comparing images with a golden file works, though JSON snapshots are usually a better way to check styling, since they don't change when a font does.