transcience/tests/unit/test_ui_theme.gd

extends GutTest
## The control theme. A missing texture gives a null and a silently unstyled
## control, which looks exactly like the theme never having been applied -- so
## every path is checked rather than assumed.


func test_every_declared_texture_loads() -> void:
	for key in UiTheme.TEXTURES:
		var tex := UiTheme.texture(key)
		assert_not_null(tex, "%s (%s) did not load" % [key, UiTheme.TEXTURES[key]])
		assert_gt(tex.get_width(), 0)
		assert_gt(tex.get_height(), 0)


func test_the_theme_styles_the_controls_the_game_actually_builds() -> void:
	var t := UiTheme.get_theme()
	for state in ["normal", "hover", "pressed", "disabled", "focus"]:
		assert_true(t.has_stylebox(state, "Button"), "Button has no %s style" % state)
	assert_true(t.has_stylebox("panel", "Panel"))
	assert_true(t.has_stylebox("panel", "PanelContainer"))
	assert_true(t.has_stylebox("normal", "LineEdit"))


## The pack's surfaces are cream with a black outline, so text on them has to be
## dark. Everything the game draws over the world stays light; only controls
## sitting on this art flip.
func test_text_on_the_packs_surfaces_is_dark() -> void:
	var t := UiTheme.get_theme()
	for key in ["font_color", "font_hover_color", "font_pressed_color"]:
		var c: Color = t.get_color(key, "Button")
		assert_lt(c.get_luminance(), 0.35, "%s is too light for cream art" % key)
	assert_lt((t.get_color("font_color", "LineEdit") as Color).get_luminance(), 0.35)


## Nine-patch margins are what stop a 1px border smearing across a stretched
## button. Zero margins would render as a plain stretched texture.
func test_button_styles_are_nine_patched() -> void:
	var t := UiTheme.get_theme()
	for state in ["normal", "hover", "pressed", "disabled"]:
		var sb := t.get_stylebox(state, "Button") as StyleBoxTexture
		assert_not_null(sb)
		for side in [SIDE_LEFT, SIDE_TOP, SIDE_RIGHT, SIDE_BOTTOM]:
			assert_gt(sb.get_texture_margin(side), 0.0,
				"%s has no stretch margin on side %d" % [state, side])


## The corner size cannot exceed half the sprite, or the two caps overlap and
## the middle has negative width.
func test_stretch_margins_fit_inside_their_sprites() -> void:
	var t := UiTheme.get_theme()
	for entry in [["normal", "Button"], ["panel", "Panel"], ["normal", "LineEdit"]]:
		var sb := t.get_stylebox(entry[0], entry[1]) as StyleBoxTexture
		var size := Vector2(sb.texture.get_size())
		assert_lte(sb.get_texture_margin(SIDE_LEFT) + sb.get_texture_margin(SIDE_RIGHT),
			size.x, "%s margins exceed its width" % entry[1])
		assert_lte(sb.get_texture_margin(SIDE_TOP) + sb.get_texture_margin(SIDE_BOTTOM),
			size.y, "%s margins exceed its height" % entry[1])


## Built once and shared. Themes are read-only data, so a second instance would
## be waste rather than isolation.
func test_the_theme_is_built_once() -> void:
	assert_eq(UiTheme.get_theme(), UiTheme.get_theme())


## The four button states have to be four different pictures, or the interface
## gives no feedback and the pack's state art is going unused.
func test_the_button_states_are_visually_distinct() -> void:
	var seen := {}
	for key in ["button", "button_hover", "button_pressed", "button_disabled"]:
		seen[UiTheme.TEXTURES[key]] = true
	assert_eq(seen.size(), 4, "two button states share a texture")


## The inventory draws slots at exactly twice the source size. A non-integer
## scale on pixel art with nearest filtering gives uneven pixel widths, which on
## a 1px border reads as a wobble along every edge.
func test_the_inventory_slot_is_drawn_at_a_whole_multiple() -> void:
	var slot := UiTheme.texture("slot")
	var scale := HUD_SLOT / float(slot.get_width())
	assert_eq(scale, floorf(scale), "slot art is scaled by %f" % scale)
	assert_eq(slot.get_width(), slot.get_height(), "the slot should be square")


const HUD_SLOT := 64.0


## A Control resolves its theme by walking up the parent chain, which is why
## one assignment near the root covers screens that share no parent. Checked on
## the mechanism rather than on a Window, so it runs headless.
func test_the_theme_reaches_controls_through_their_ancestors() -> void:
	var root: Control = autofree(Control.new())
	root.theme = UiTheme.get_theme()
	var middle := Control.new()
	root.add_child(middle)
	var button := Button.new()
	middle.add_child(button)
	assert_eq(button.get_theme_stylebox("normal", "Button"),
		UiTheme.get_theme().get_stylebox("normal", "Button"),
		"a button two levels down should still find the theme")
	assert_eq(button.get_theme_color("font_color", "Button"), UiTheme.INK)


func test_applying_to_nothing_is_harmless() -> void:
	UiTheme.apply_to(null)
	assert_true(true, "a null root must not be a crash")


func test_a_themed_root_fills_its_parent_and_carries_the_theme() -> void:
	var root: Control = autofree(UiTheme.themed_root())
	assert_eq(root.theme, UiTheme.get_theme())
	assert_eq(root.anchor_right, 1.0)
	assert_eq(root.anchor_bottom, 1.0)


## Every screen in the game is built in code and hangs off either a plain Node
## or a CanvasLayer, and theme inheritance travels Control-to-Control ONLY --
## the chain breaks at the first non-Control parent. Setting the theme once on
## the Window therefore looked like it worked and styled nothing, which is a
## mistake that is invisible until somebody looks at the screen. So: every
## screen is instantiated here and asked what its buttons actually resolve.
func test_every_screen_actually_gets_the_theme() -> void:
	var screens := {
		"HUD": "res://src/ui/hud.gd",
		"GameMenu": "res://src/ui/game_menu.gd",
		"CharacterSelect": "res://src/ui/character_select.gd",
		"UpgradeScreen": "res://src/ui/upgrade_screen.gd",
		"SettingsScreen": "res://src/ui/settings_screen.gd",
		"CreditsScreen": "res://src/ui/credits_screen.gd",
		"MainMenu": "res://src/ui/main_menu.gd",
	}
	var wanted := UiTheme.get_theme().get_stylebox("normal", "Button")
	for name in screens:
		var node: Node = (load(screens[name]) as Script).new()
		add_child_autofree(node)
		var buttons := node.find_children("*", "Button", true, false)
		assert_gt(buttons.size(), 0, "%s has no button to check" % name)
		for b: Button in buttons:
			assert_eq(b.get_theme_stylebox("normal", "Button"), wanted,
				"%s: '%s' is not themed" % [name, b.text])


## A Slider draws its groove in a band whose thickness is the stylebox's own
## minimum size -- which for a StyleBoxTexture is its content margins. With
## those at zero the track resolves, reports the right texture, and draws
## nothing, which is exactly what it did.
func test_slider_styleboxes_have_a_thickness() -> void:
	var t := UiTheme.get_theme()
	for key in ["slider", "grabber_area", "grabber_area_highlight"]:
		var sb := t.get_stylebox(key, "HSlider")
		assert_gt(sb.get_minimum_size().y, 0.0,
			"HSlider/%s would draw with no height" % key)


## The filled portion has to sit inside the groove, not overhang it.
func test_the_filled_portion_is_no_thicker_than_the_groove() -> void:
	var t := UiTheme.get_theme()
	assert_lte(t.get_stylebox("grabber_area", "HSlider").get_minimum_size().y,
		t.get_stylebox("slider", "HSlider").get_minimum_size().y)


func test_the_slider_grabber_is_big_enough_to_aim_at() -> void:
	var grab := UiTheme.get_theme().get_icon("grabber", "HSlider")
	assert_not_null(grab)
	assert_gte(grab.get_width(), 12, "an 8px grabber is a speck at this scale")
	assert_lte(grab.get_height(), 26, "and one taller than its row overflows it")


## Nearest-neighbour and a whole multiple, or the pixel art turns to mush.
func test_scaling_a_sprite_keeps_it_a_whole_multiple() -> void:
	var src := UiTheme.texture("grabber")
	var out := UiTheme.scaled("grabber", 2)
	assert_eq(out.get_width(), src.get_width() * 2)
	assert_eq(out.get_height(), src.get_height() * 2)


## Every scrollbar piece has to be styled or the default grey chrome shows
## through on the two screens that scroll.
func test_scrollbars_are_styled() -> void:
	var t := UiTheme.get_theme()
	for bar_class in ["VScrollBar", "HScrollBar"]:
		for key in ["scroll", "grabber", "grabber_highlight", "grabber_pressed"]:
			assert_true(t.has_stylebox(key, bar_class),
				"%s/%s is unstyled" % [bar_class, key])


## And they need a thickness, for the same reason sliders do: a ScrollBar sizes
## itself from its styleboxes' minimum size, so styling one with no content
## margins produces a bar zero pixels wide -- which looks exactly like having
## no scrollbar, and did.
func test_scrollbars_have_a_thickness_in_both_directions() -> void:
	var t := UiTheme.get_theme()
	for bar_class in ["VScrollBar", "HScrollBar"]:
		for key in ["scroll", "grabber"]:
			var size := t.get_stylebox(key, bar_class).get_minimum_size()
			assert_gt(size.x, 0.0, "%s/%s has no width" % [bar_class, key])
			assert_gt(size.y, 0.0, "%s/%s has no height" % [bar_class, key])


## Panels are the pack's shape in this game's colours: the art is cream, and a
## cream dialog over a dark dungeon would need every label in five screens
## recoloured. Tinting the stylebox keeps the border and the existing text.
func test_dialog_panels_are_tinted_dark() -> void:
	var sb := UiTheme.get_theme().get_stylebox("panel", "PanelContainer") as StyleBoxTexture
	assert_lt(sb.modulate_color.get_luminance(), 0.35,
		"a bright panel would make every light label on it unreadable")
	assert_gt(sb.get_minimum_size().x, 0.0, "a dialog needs padding")


func test_a_card_panel_carries_its_tint() -> void:
	var card: PanelContainer = autofree(UiTheme.card_panel(Color(0.9, 0.2, 0.2)))
	var sb := card.get_theme_stylebox("panel") as StyleBoxTexture
	assert_not_null(sb)
	assert_almost_eq(sb.modulate_color.r, 0.9, 0.001)