const std = @import("std");
const testing = std.testing;

const act = @import("action");
const input = @import("input");
const font = @import("font.zig");
const layout = @import("layout.zig");
const Box = layout.Box;

comptime {
    _ = act;
    _ = input;
    _ = @import("color.zig");
}

const area: Box = .{ .x = 0, .y = 0, .width = 1000, .height = 600 };

fn params(nmaster: u32, mfact: f32) layout.Params {
    return .{ .area = area, .nmaster = nmaster, .mfact = mfact };
}

// ─── master/stack tiling ─────────────────────────────────────────────────────

test "single window fills the whole area" {
    var cells: [1]Box = undefined;
    _ = layout.arrange(.master, params(1, 0.55), &cells);
    try testing.expectEqual(area, cells[0]);
}

test "two windows split at mfact" {
    var cells: [2]Box = undefined;
    _ = layout.arrange(.master, params(1, 0.55), &cells);

    try testing.expectEqual(@as(i32, 550), cells[0].width);
    try testing.expectEqual(@as(i32, 600), cells[0].height);

    try testing.expectEqual(@as(i32, 550), cells[1].x);
    try testing.expectEqual(@as(i32, 450), cells[1].width);
    try testing.expectEqual(@as(i32, 600), cells[1].height);
}

test "stack column divides height with no gap or overlap" {
    // Three windows, one master: the stack column holds two.
    var cells: [3]Box = undefined;
    _ = layout.arrange(.master, params(1, 0.5), &cells);

    try testing.expectEqual(@as(i32, 600), cells[0].height);
    try testing.expectEqual(cells[1].y + cells[1].height, cells[2].y);
    try testing.expectEqual(area.height, cells[1].height + cells[2].height);
}

test "odd heights are absorbed rather than leaving a gap at the bottom" {
    // 600 / 7 does not divide evenly; the last window must still end exactly
    // at the bottom edge.
    var cells: [7]Box = undefined;
    _ = layout.arrange(.master, params(0, 0.55), &cells);

    var y: i32 = area.y;
    for (cells) |cell| {
        try testing.expectEqual(y, cell.y);
        y += cell.height;
    }
    try testing.expectEqual(area.y + area.height, y);
}

test "nmaster zero puts every window in the stack column" {
    var cells: [3]Box = undefined;
    _ = layout.arrange(.master, params(0, 0.55), &cells);
    for (cells) |cell| {
        try testing.expectEqual(@as(i32, 0), cell.x);
        try testing.expectEqual(area.width, cell.width);
    }
}

test "windows all fit in master when count does not exceed nmaster" {
    var cells: [2]Box = undefined;
    _ = layout.arrange(.master, params(3, 0.55), &cells);
    // No stack column, so master spans the full width.
    for (cells) |cell| {
        try testing.expectEqual(area.width, cell.width);
    }
    try testing.expectEqual(area.height, cells[0].height + cells[1].height);
}

test "master column also divides height when nmaster exceeds one" {
    var cells: [4]Box = undefined;
    _ = layout.arrange(.master, params(2, 0.5), &cells);

    try testing.expectEqual(@as(i32, 500), cells[0].width);
    try testing.expectEqual(@as(i32, 500), cells[1].width);
    try testing.expectEqual(area.height, cells[0].height + cells[1].height);
    try testing.expectEqual(area.height, cells[2].height + cells[3].height);
}

// ─── stacking layouts ────────────────────────────────────────────────────────

test "monocle gives every window the full area and reports stacked" {
    var cells: [3]Box = undefined;
    const result = layout.arrange(.monocle, params(1, 0.55), &cells);

    try testing.expect(result.stacked);
    try testing.expect(result.tabbar == null);
    for (cells) |cell| try testing.expectEqual(area, cell);
}

test "master does not report stacked" {
    var cells: [2]Box = undefined;
    var p = params(1, 0.55);
    p.tabbar_height = 22;

    try testing.expect(!layout.arrange(.master, p, &cells).stacked);
}

test "tabbed reserves the bar strip above the windows" {
    var cells: [3]Box = undefined;
    var p = params(1, 0.55);
    p.tabbar_height = 22;
    const result = layout.arrange(.tabbed, p, &cells);

    try testing.expect(result.stacked);
    const bar = result.tabbar.?;
    try testing.expectEqual(@as(i32, 22), bar.height);
    try testing.expectEqual(area.y, bar.y);

    // Windows start below the bar and the two together cover the area exactly.
    for (cells) |cell| {
        try testing.expectEqual(area.y + 22, cell.y);
        try testing.expectEqual(area.height - 22, cell.height);
    }
}

test "tabbed drops the bar rather than crushing the windows" {
    var cells: [2]Box = undefined;
    var p: layout.Params = .{
        .area = .{ .x = 0, .y = 0, .width = 400, .height = 30 },
        .nmaster = 1,
        .mfact = 0.55,
        .tabbar_height = 22,
    };
    const result = layout.arrange(.tabbed, p, &cells);
    try testing.expect(result.tabbar == null);
    try testing.expectEqual(@as(i32, 30), cells[0].height);
    p.tabbar_height = 0;
}

test "no windows is not a crash" {
    var cells: [0]Box = undefined;
    const result = layout.arrange(.master, params(1, 0.55), &cells);
    try testing.expect(result.tabbar == null);
}

// ─── gaps ────────────────────────────────────────────────────────────────────

test "outer gap insets the whole area" {
    var cells: [1]Box = undefined;
    var p = params(1, 0.55);
    p.outer_gap = 10;
    _ = layout.arrange(.master, p, &cells);

    try testing.expectEqual(@as(i32, 10), cells[0].x);
    try testing.expectEqual(@as(i32, 10), cells[0].y);
    try testing.expectEqual(@as(i32, 980), cells[0].width);
    try testing.expectEqual(@as(i32, 580), cells[0].height);
}

test "inner gap separates adjacent windows" {
    var cells: [2]Box = undefined;
    var p = params(1, 0.5);
    p.gap = 10;
    _ = layout.arrange(.master, p, &cells);

    // Each cell shrinks by half the gap per side, leaving a full gap between.
    const right_of_master = cells[0].x + cells[0].width;
    try testing.expect(cells[1].x - right_of_master == 10);
}

// ─── tab rectangles ──────────────────────────────────────────────────────────

test "tab rects tile the bar exactly with no rounding gap" {
    const bar: Box = .{ .x = 5, .y = 0, .width = 101, .height = 22 };
    var rects: [4]Box = undefined;
    layout.tabRects(bar, 4, &rects);

    try testing.expectEqual(bar.x, rects[0].x);
    var total: i32 = 0;
    for (rects, 0..) |rect, i| {
        total += rect.width;
        if (i > 0) {
            try testing.expectEqual(rects[i - 1].x + rects[i - 1].width, rect.x);
        }
    }
    try testing.expectEqual(bar.width, total);
    try testing.expectEqual(bar.x + bar.width, rects[3].x + rects[3].width);
}

test "single tab spans the bar" {
    const bar: Box = .{ .x = 0, .y = 0, .width = 300, .height = 22 };
    var rects: [1]Box = undefined;
    layout.tabRects(bar, 1, &rects);
    try testing.expectEqual(@as(i32, 300), rects[0].width);
}

// ─── Box helpers ─────────────────────────────────────────────────────────────

test "inset never produces negative dimensions" {
    const tiny: Box = .{ .x = 0, .y = 0, .width = 4, .height = 4 };
    const r = tiny.inset(10);
    try testing.expectEqual(@as(i32, 0), r.width);
    try testing.expectEqual(@as(i32, 0), r.height);
}

test "contains is half open on the far edges" {
    const b: Box = .{ .x = 10, .y = 10, .width = 100, .height = 50 };
    try testing.expect(b.contains(10, 10));
    try testing.expect(b.contains(109, 59));
    try testing.expect(!b.contains(110, 30));
    try testing.expect(!b.contains(9, 30));
}

// ─── per-tag settings slots ──────────────────────────────────────────────────

test "each single tag gets its own settings slot" {
    for (0..act.tag_count) |i| {
        const mask = @as(u32, 1) << @intCast(i);
        try testing.expectEqual(i + 1, act.tagSlot(mask));
    }
}

test "views of more than one tag share the shared slot" {
    try testing.expectEqual(@as(usize, 0), act.tagSlot(0b11));
    try testing.expectEqual(@as(usize, 0), act.tagSlot(0b101));
    try testing.expectEqual(@as(usize, 0), act.tagSlot(act.all_tags));
}

test "an empty view falls back to the shared slot" {
    try testing.expectEqual(@as(usize, 0), act.tagSlot(0));
}

test "bits above the tag range do not affect the slot" {
    // A single valid tag stays on its own slot even with junk in the high bits,
    // so a mask that survived a sloppy IPC caller cannot index past the array.
    const junk: u32 = ~act.all_tags;
    try testing.expectEqual(@as(usize, 1), act.tagSlot(0b1 | junk));
    try testing.expectEqual(act.tag_count, act.tagSlot(@as(u32, 1) << (act.tag_count - 1)));
}

// ─── splitting the tag set across screens ────────────────────────────────────

test "a lone screen owns every tag" {
    try testing.expectEqual(act.all_tags, act.tagsForOutput(0, 1));
    // No screens at all is not a case callers should have to think about.
    try testing.expectEqual(act.all_tags, act.tagsForOutput(0, 0));
}

test "two screens split the tags into contiguous halves" {
    // Nine tags do not halve evenly; the left screen takes the extra one.
    try testing.expectEqual(@as(u32, 0b000011111), act.tagsForOutput(0, 2));
    try testing.expectEqual(@as(u32, 0b111100000), act.tagsForOutput(1, 2));
}

test "three screens split the tags into thirds" {
    try testing.expectEqual(@as(u32, 0b000000111), act.tagsForOutput(0, 3));
    try testing.expectEqual(@as(u32, 0b000111000), act.tagsForOutput(1, 3));
    try testing.expectEqual(@as(u32, 0b111000000), act.tagsForOutput(2, 3));
}

test "every tag lands on exactly one screen" {
    // The whole point of the split: no tag is shared and none goes missing,
    // whatever the screen count.
    for (1..act.tag_count + 1) |count| {
        var seen: u32 = 0;
        for (0..count) |i| {
            const mask = act.tagsForOutput(i, count);
            try testing.expect(mask != 0);
            try testing.expectEqual(@as(u32, 0), seen & mask);
            seen |= mask;
        }
        try testing.expectEqual(act.all_tags, seen);
    }
}

test "ranges are contiguous and in screen order" {
    for (1..act.tag_count + 1) |count| {
        var next: u32 = 0;
        for (0..count) |i| {
            const mask = act.tagsForOutput(i, count);
            // Contiguous: a run of ones, starting where the last range ended.
            const lowest = @ctz(mask);
            const past_highest = 32 - @clz(mask);
            try testing.expectEqual(next, lowest);
            try testing.expectEqual(past_highest - lowest, @popCount(mask));
            next = past_highest;
        }
    }
}

test "more screens than tags leaves no screen without one" {
    // Twelve monitors and nine tags: the ones past the end share the last tag
    // rather than being handed an empty mask, which could show nothing at all.
    const count = act.tag_count + 3;
    for (0..count) |i| {
        try testing.expect(act.tagsForOutput(i, count) != 0);
    }
    try testing.expectEqual(act.tagsForOutput(act.tag_count - 1, count), act.tagsForOutput(count - 1, count));
}

test "a screen index past the end owns everything rather than nothing" {
    try testing.expectEqual(act.all_tags, act.tagsForOutput(2, 2));
}

test "the lowest tag is what a stranded view falls back to" {
    try testing.expectEqual(@as(u32, 0b100000), act.lowestTag(0b111100000));
    try testing.expectEqual(@as(u32, 1), act.lowestTag(act.all_tags));
    try testing.expectEqual(@as(u32, 0), act.lowestTag(0));
    // Junk above the tag range is not a tag to fall back to.
    try testing.expectEqual(@as(u32, 0), act.lowestTag(~act.all_tags));
}

// ─── command parsing ─────────────────────────────────────────────────────────

fn parseOk(argv: []const []const u8) act.Action {
    return act.parse(argv) catch unreachable;
}

test "tag arguments accept indices, masks and all" {
    try testing.expectEqual(@as(u32, 1), parseOk(&.{ "view", "1" }).view);
    try testing.expectEqual(@as(u32, 4), parseOk(&.{ "view", "3" }).view);
    try testing.expectEqual(@as(u32, 4), parseOk(&.{ "view", "0x4" }).view);
    try testing.expectEqual(@as(u32, 4), parseOk(&.{ "view", "mask:4" }).view);
    try testing.expectEqual(act.all_tags, parseOk(&.{ "view", "all" }).view);
}

test "tag indices outside the range are rejected" {
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "view", "0" }));
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "view", "10" }));
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "view", "nope" }));
    try testing.expectError(error.MissingArgument, act.parse(&.{"view"}));
}

test "masks are clamped to the valid tag range" {
    try testing.expectEqual(act.all_tags, parseOk(&.{ "view", "0xffffffff" }).view);
}

test "deltas distinguish relative from absolute" {
    switch (parseOk(&.{ "mfact", "+0.05" }).mfact) {
        .relative => |v| try testing.expectApproxEqAbs(@as(f32, 0.05), v, 1e-6),
        .absolute => return error.TestUnexpectedResult,
    }
    switch (parseOk(&.{ "mfact", "0.5" }).mfact) {
        .absolute => |v| try testing.expectApproxEqAbs(@as(f32, 0.5), v, 1e-6),
        .relative => return error.TestUnexpectedResult,
    }
    switch (parseOk(&.{ "nmaster", "-1" }).nmaster) {
        .relative => |v| try testing.expectEqual(@as(i32, -1), v),
        .absolute => return error.TestUnexpectedResult,
    }
}

test "delta application respects relative and absolute" {
    const rel = act.Delta(i32){ .relative = -1 };
    const abs = act.Delta(i32){ .absolute = 3 };
    try testing.expectEqual(@as(i32, 4), rel.apply(5));
    try testing.expectEqual(@as(i32, 3), abs.apply(5));
}

test "unknown commands are rejected rather than guessed at" {
    try testing.expectError(error.UnknownCommand, act.parse(&.{"nonsense"}));
    try testing.expectError(error.UnknownCommand, act.parse(&.{}));
}

test "spawn keeps its whole argv" {
    const a = parseOk(&.{ "spawn", "foot", "-e", "htop" });
    try testing.expectEqual(@as(usize, 3), a.spawn.len);
    try testing.expectEqualStrings("htop", a.spawn[2]);
    try testing.expectError(error.MissingArgument, act.parse(&.{"spawn"}));
}

test "directions parse both spellings" {
    try testing.expectEqual(act.Direction.next, parseOk(&.{ "focus", "next" }).focus);
    try testing.expectEqual(act.Direction.prev, parseOk(&.{ "focus", "prev" }).focus);
    try testing.expectEqual(act.Direction.prev, parseOk(&.{ "focus", "previous" }).focus);
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "focus", "sideways" }));
}

test "window commands keep the identifier verbatim" {
    try testing.expectEqualStrings("w-17", parseOk(&.{ "focus-window", "w-17" }).focus_window);
    try testing.expectEqualStrings("w-17", parseOk(&.{ "close-window", "w-17" }).close_window);
    // An identifier is opaque, so a direction-looking one is still an id.
    try testing.expectEqualStrings("next", parseOk(&.{ "focus-window", "next" }).focus_window);
    try testing.expectError(error.MissingArgument, act.parse(&.{"focus-window"}));
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "focus-window", "" }));
}

test "layouts parse by name" {
    try testing.expectEqual(act.Layout.monocle, parseOk(&.{ "layout", "monocle" }).set_layout);
    try testing.expectEqual(act.Layout.tabbed, parseOk(&.{ "layout", "tabbed" }).set_layout);
    try testing.expectError(error.InvalidArgument, act.parse(&.{ "layout", "spiral" }));
}

test "only navigation-style actions repeat on key hold" {
    try testing.expect(parseOk(&.{ "focus", "next" }).repeats());
    try testing.expect(parseOk(&.{ "mfact", "+0.05" }).repeats());
    try testing.expect(!parseOk(&.{"zoom"}).repeats());
    try testing.expect(!parseOk(&.{"close"}).repeats());
    try testing.expect(!parseOk(&.{ "view", "1" }).repeats());
}

// ─── input device rules ──────────────────────────────────────────────────────

test "device name globs match the way a config author expects" {
    const touchpad = "ELAN0501:00 04F3:3060 Touchpad";

    try testing.expect(input.matches("*Touchpad*", touchpad));
    try testing.expect(input.matches("*Touchpad", touchpad));
    try testing.expect(input.matches("ELAN*", touchpad));
    try testing.expect(input.matches("*", touchpad));
    try testing.expect(input.matches(touchpad, touchpad));

    try testing.expect(!input.matches("*Trackpoint*", touchpad));
    try testing.expect(!input.matches("Touchpad", touchpad));
    // A literal pattern must match the whole name, not merely a prefix.
    try testing.expect(!input.matches("ELAN0501", touchpad));
}

test "globs handle empty runs and repeated stars" {
    try testing.expect(input.matches("", ""));
    try testing.expect(input.matches("*", ""));
    try testing.expect(input.matches("***", ""));
    try testing.expect(!input.matches("a", ""));

    // The backtracking case: each star has to be willing to give ground.
    try testing.expect(input.matches("*a*b*c*", "xxaxxbxxcxx"));
    try testing.expect(!input.matches("*a*b*c*", "xxaxxcxxbxx"));
    // Only the last 'a' lets the rest of the pattern through.
    try testing.expect(input.matches("*aab", "aaab"));
}

test "rules match on name and type independently" {
    const rule: input.Rule = .{ .name = "*Touchpad*", .type = .pointer, .tap = true };

    try testing.expect(rule.matchesDevice("Foo Touchpad", .pointer));
    // Right name, wrong kind of device.
    try testing.expect(!rule.matchesDevice("Foo Touchpad", .touch));
    try testing.expect(!rule.matchesDevice("Foo Keyboard", .pointer));

    // A rule with neither selector applies to everything.
    const catch_all: input.Rule = .{ .natural_scroll = true };
    try testing.expect(catch_all.matchesDevice("anything", .tablet));
    try testing.expect(catch_all.matchesDevice("", .keyboard));
}

test "later rules override earlier ones field by field" {
    const broad: input.Rule = .{ .name = "*", .tap = true, .natural_scroll = true };
    const narrow: input.Rule = .{ .name = "*Touchpad*", .tap = false, .click_method = .clickfinger };

    const merged = (input.Rule{}).merge(broad).merge(narrow);

    // Stated twice: the later rule wins.
    try testing.expectEqual(@as(?bool, false), merged.tap);
    // Stated only by the broad rule: survives.
    try testing.expectEqual(@as(?bool, true), merged.natural_scroll);
    // Stated only by the narrow rule: applied.
    try testing.expectEqual(@as(?input.ClickMethod, .clickfinger), merged.click_method);
    // Stated by neither: still null, so the device keeps libinput's default.
    try testing.expectEqual(@as(?bool, null), merged.middle_emulation);
}

test "merging leaves the selectors alone" {
    // Otherwise a merged rule would claim to be about whichever device matched
    // last, which is not a thing anything should be able to read back out.
    const merged = (input.Rule{ .name = "a", .type = .pointer })
        .merge(.{ .name = "b", .type = .keyboard, .tap = true });

    try testing.expectEqualStrings("a", merged.name.?);
    try testing.expectEqual(@as(?input.Type, .pointer), merged.type);
    try testing.expectEqual(@as(?bool, true), merged.tap);
}

test "an unset keymap is recognised as the default" {
    try testing.expect((input.Keymap{}).isDefault());
    try testing.expect(!(input.Keymap{ .layout = "us" }).isDefault());
    try testing.expect(!(input.Keymap{ .options = "caps:escape" }).isDefault());
}

test "map_to_output merges like any other setting" {
    // It is a string rather than a scalar, so worth pinning that the generic
    // merge handles it and that a rule silent about it does not clear it.
    const merged = (input.Rule{})
        .merge(.{ .type = .touch, .map_to_output = "eDP-1" })
        .merge(.{ .name = "*", .tap = true });

    try testing.expectEqualStrings("eDP-1", merged.map_to_output.?);

    // And that a later rule naming a different output does win.
    const moved = merged.merge(.{ .map_to_output = "DP-2" });
    try testing.expectEqualStrings("DP-2", moved.map_to_output.?);
}

// ─── tab titles ──────────────────────────────────────────────────────────────

/// Stands in for a `Face`, so the eliding rules can be checked without a font
/// on the machine running the tests. One cell wide per character, in the 26.6
/// units `font.fit` counts in.
const Mono = struct {
    pub fn advance(_: Mono, _: u21) i32 {
        return font.fixed(1);
    }
    pub fn ellipsisAdvance(self: Mono) i32 {
        return self.advance(font.ellipsis);
    }
};

/// A proportional face: 'i' is half a cell, the ellipsis two. Real faces are
/// like this, and it is where fixed-cell arithmetic goes wrong.
const Prop = struct {
    pub fn advance(_: Prop, cp: u21) i32 {
        return switch (cp) {
            'i' => @divExact(font.fixed(1), 2),
            font.ellipsis => font.fixed(2),
            else => font.fixed(1),
        };
    }
    pub fn ellipsisAdvance(self: Prop) i32 {
        return self.advance(font.ellipsis);
    }
};

test "a title that fits is drawn whole" {
    const f = font.fit("foot", font.fixed(10), Mono{});
    try testing.expectEqual(@as(usize, 4), f.end);
    try testing.expectEqual(font.fixed(4), f.width);
    try testing.expect(!f.elided);

    // Exactly full is still whole: the ellipsis costs room, so only spend it
    // when something is actually cut.
    const exact = font.fit("foot", font.fixed(4), Mono{});
    try testing.expectEqual(@as(usize, 4), exact.end);
    try testing.expect(!exact.elided);
}

test "a title too long for the tab is cut short for the ellipsis" {
    const f = font.fit("firefox", font.fixed(4), Mono{});
    try testing.expectEqualStrings("fir", "firefox"[0..f.end]);
    try testing.expectEqual(font.fixed(4), f.width);
    try testing.expect(f.elided);

    // Room for the ellipsis alone leaves nothing but the ellipsis, and no room
    // at all draws nothing rather than indexing past the end.
    const one = font.fit("firefox", font.fixed(1), Mono{});
    try testing.expectEqual(@as(usize, 0), one.end);
    try testing.expect(one.elided);

    const none = font.fit("firefox", 0, Mono{});
    try testing.expectEqual(@as(usize, 0), none.end);
    try testing.expect(!none.elided);
}

test "eliding gives up as many characters as the ellipsis costs" {
    // "wiki" alone would fit in three cells; the two-cell ellipsis means all
    // but the first character has to go, which counting cells would miss.
    const f = font.fit("wikiw", font.fixed(3), Prop{});
    try testing.expect(f.elided);
    try testing.expectEqualStrings("w", "wikiw"[0..f.end]);
    try testing.expect(f.width <= font.fixed(3));

    // Narrow characters earn their place: three of them survive where two wide
    // ones would not.
    const narrow = font.fit("wiiwwww", font.fixed(4), Prop{});
    try testing.expect(narrow.elided);
    try testing.expectEqualStrings("wii", "wiiwwww"[0..narrow.end]);
    try testing.expect(narrow.width <= font.fixed(4));
}

test "titles are measured in characters, not bytes" {
    // Four codepoints, six bytes: a tab four cells wide holds them all.
    const f = font.fit("ünïx", font.fixed(4), Mono{});
    try testing.expectEqual("ünïx".len, f.end);
    try testing.expect(!f.elided);

    // And a cut lands on a codepoint boundary, never mid-sequence.
    const cut = font.fit("ünïx", font.fixed(3), Mono{});
    try testing.expect(cut.elided);
    try testing.expectEqualStrings("ün", "ünïx"[0..cut.end]);
}

test "malformed utf-8 in a title yields one glyph per bad byte" {
    var it: font.Iterator = .{ .bytes = "a\xffb\xc3" };
    try testing.expectEqual(@as(?u21, 'a'), it.next());
    try testing.expectEqual(@as(?u21, 0xfffd), it.next());
    try testing.expectEqual(@as(?u21, 'b'), it.next());
    // A truncated sequence at the end must terminate the walk, not loop.
    try testing.expectEqual(@as(?u21, 0xfffd), it.next());
    try testing.expectEqual(@as(?u21, null), it.next());
}

test "control characters in a title draw as spaces" {
    var it: font.Iterator = .{ .bytes = "a\nb\tc\x7f" };
    try testing.expectEqual(@as(?u21, 'a'), it.next());
    try testing.expectEqual(@as(?u21, ' '), it.next());
    try testing.expectEqual(@as(?u21, 'b'), it.next());
    try testing.expectEqual(@as(?u21, ' '), it.next());
    try testing.expectEqual(@as(?u21, 'c'), it.next());
    try testing.expectEqual(@as(?u21, ' '), it.next());
    try testing.expectEqual(@as(?u21, null), it.next());
}

test "fixed point widths round up to whole pixels" {
    try testing.expectEqual(@as(i32, 0), font.pixels(0));
    try testing.expectEqual(@as(i32, 1), font.pixels(1));
    try testing.expectEqual(@as(i32, 1), font.pixels(font.fixed(1)));
    try testing.expectEqual(@as(i32, 2), font.pixels(font.fixed(1) + 1));
}