siftlode/frontend/src/components/ui/Button.dom.test.tsx

// @vitest-environment jsdom
//
// The shared <Button> primitive. These lock the load-bearing contract the migrated call sites rely
// on: variant/size paint (the DESIGN.md B1 ladder and B3 layers), the loading state (disabled +
// spinner + aria-busy), the pressed toggle, and the type="button" default that stops an action button from
// submitting a surrounding form. A glyph-only button is `IconButton` (its own test).
import { afterEach, describe, expect, it, vi } from "vitest";
import { act, render, screen, cleanup, fireEvent } from "@testing-library/react";
import { Button } from "./Button";

afterEach(cleanup);

describe("Button primitive", () => {
  it("defaults to type=button so it never submits a form", () => {
    render(<Button>Go</Button>);
    expect(screen.getByRole("button", { name: "Go" }).getAttribute("type")).toBe("button");
  });

  it("applies the variant paint recipe", () => {
    render(
      <Button variant="danger" size="sm">
        Delete
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Delete" });
    expect(btn.className).toContain("state-danger");
    expect(btn.className).toContain("h-7");
  });

  it("puts every rung on an explicit height, so a toolbar row lines up (B1)", () => {
    for (const [size, h] of [
      ["xs", "h-6"],
      ["sm", "h-7"],
      ["md", "h-8"],
    ] as const) {
      const { unmount } = render(<Button size={size}>X</Button>);
      const cls = screen.getByRole("button", { name: "X" }).className.split(/\s+/);
      expect(cls).toContain(h);
      expect(cls).toContain("rounded-lg");
      expect(cls.filter((c) => c.startsWith("py-"))).toEqual([]);
      unmount();
    }
  });

  it("hovers with a state layer, never an opacity dim or a card fill (B3)", () => {
    for (const variant of ["outline", "ghost", "outline-danger", "danger-soft"] as const) {
      const { unmount } = render(<Button variant={variant}>X</Button>);
      const cls = screen.getByRole("button", { name: "X" }).className;
      expect(cls).toContain("state-layer");
      expect(cls).not.toMatch(/hover:(bg-card|bg-surface|opacity)/);
      unmount();
    }
  });

  it("a lit cycle paints the pressed look without announcing a toggle", () => {
    render(
      <Button variant="overlay" lit>
        Loop: All
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Loop: All" });
    expect(btn.hasAttribute("aria-pressed")).toBe(false);
    expect(btn.hasAttribute("data-lit")).toBe(true);
    expect(btn.className).toContain("data-lit:bg-accent");
  });

  it("a toggle announces aria-pressed and paints the pressed state", () => {
    const { rerender } = render(
      <Button variant="outline" pressed={false}>
        Default
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Default" });
    expect(btn.getAttribute("aria-pressed")).toBe("false");
    expect(btn.className).toContain("aria-pressed:bg-accent");
    rerender(
      <Button variant="outline" pressed>
        Default
      </Button>,
    );
    expect(btn.getAttribute("aria-pressed")).toBe("true");
  });

  it("loading marks aria-busy + aria-disabled, blocks clicks, and swaps the icon", () => {
    const onClick = vi.fn();
    render(
      <Button loading icon={<svg data-testid="ic" />} onClick={onClick}>
        Save
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Save" }) as HTMLButtonElement;
    expect(btn.getAttribute("aria-busy")).toBe("true");
    expect(btn.getAttribute("aria-disabled")).toBe("true");
    // the leading icon is swapped for a spinner
    expect(btn.querySelector("[data-testid=ic]")).toBeNull();
    fireEvent.click(btn);
    expect(onClick).not.toHaveBeenCalled();
  });

  // Measured in Chrome: a focused button that becomes natively disabled drops the focus to
  // <body> and never gets it back, so every "Something else" press threw a keyboard user out of Home.
  // jsdom has no focus fixup, so what is pinned here is the cause — native `disabled` stays off.
  it("loading keeps the button natively enabled, so it keeps the focus", () => {
    render(<Button loading>Reroll</Button>);
    const btn = screen.getByRole("button", { name: "Reroll" }) as HTMLButtonElement;
    expect(btn.disabled).toBe(false);
  });

  it("loading blocks clicks even when an explicit disabled={false} is passed", () => {
    // Regression: `disabled ?? loading` let an explicit boolean disabled shadow loading, so a
    // call-site with `disabled={!valid} loading={pending}` (valid → disabled=false) stayed
    // clickable mid-mutation and double-submitted. The contract is: loading always blocks.
    const onClick = vi.fn();
    render(
      <Button disabled={false} loading onClick={onClick}>
        Create
      </Button>,
    );
    fireEvent.click(screen.getByRole("button", { name: "Create" }));
    expect(onClick).not.toHaveBeenCalled();
  });

  it("a busy submit button cancels the form's submission", () => {
    // Enter in a field submits through a click on the default button; the guard cancels that click.
    const onSubmit = vi.fn((e: { preventDefault: () => void }) => e.preventDefault());
    render(
      <form onSubmit={onSubmit}>
        <Button type="submit" loading>
          Send
        </Button>
      </form>,
    );
    fireEvent.click(screen.getByRole("button", { name: "Send" }));
    expect(onSubmit).not.toHaveBeenCalled();
  });

  it("a non-busy button still calls onClick", () => {
    const onClick = vi.fn();
    render(<Button onClick={onClick}>Go</Button>);
    fireEvent.click(screen.getByRole("button", { name: "Go" }));
    expect(onClick).toHaveBeenCalledTimes(1);
  });

  it("a link gets no button padding, and an explicit size still wins", () => {
    // The size default is variant-dependent (link → "none"). Locking it because the failure is
    // silent: a link that quietly inherits px-3 py-2 reads as a button, and nothing errors.
    const { rerender } = render(<Button variant="link">Show all</Button>);
    let btn = screen.getByRole("button", { name: "Show all" });
    expect(btn.className).toContain("text-accent");
    expect(btn.className).not.toContain("px-3");
    rerender(
      <Button variant="link" size="sm">
        Show all
      </Button>,
    );
    btn = screen.getByRole("button", { name: "Show all" });
    expect(btn.className).toContain("px-2.5");
  });

  it("keeps one font-weight utility whatever the variant", () => {
    // Two font-* utilities of equal specificity are decided by stylesheet order, not class order,
    // so a variant must never add a second one (there is no tailwind-merge here).
    for (const variant of ["primary", "link", "glass", "outline"] as const) {
      const { unmount } = render(<Button variant={variant}>X</Button>);
      const cls = screen.getByRole("button", { name: "X" }).className;
      expect(cls.split(/\s+/).filter((c) => c.startsWith("font-")).length).toBe(1);
      unmount();
    }
  });

  it("carries the coarse-pointer minimum target and the 24 floor, a link variant too", () => {
    // The tablet comfort contract: the minimum lives in the primitive, so no call site can opt
    // out of it by accident. A link variant was once excluded as "text in a sentence", but every
    // one stands alone, and an audit measured them at 16–20px.
    const { unmount } = render(<Button>Tap</Button>);
    expect(screen.getByRole("button", { name: "Tap" }).className).toContain("touch-target");
    unmount();
    for (const variant of ["link", "link-muted"] as const) {
      const { unmount: u } = render(<Button variant={variant}>Read more</Button>);
      const cls = screen.getByRole("button", { name: "Read more" }).className;
      expect(cls).toContain("touch-target");
      expect(cls).toContain("min-h-6");
      u();
    }
  });

  it("fullWidth adds the w-full utility", () => {
    render(<Button fullWidth>Wide</Button>);
    expect(screen.getByRole("button", { name: "Wide" }).className).toContain("w-full");
  });
});

// --- the accessible-name contract, pinned at the TYPE level ------------------------------------
// A button that renders no text must carry a name, and that rule is a union in Button.tsx rather
// than a doc comment because the comment version let two nameless icon buttons ship. But a
// type with no test is a type someone widens to silence a stubborn call site:
// replacing `ButtonProps` with the permissive shape left tsc, eslint, knip and vitest all green.
// Each `@ts-expect-error` below FAILS THE BUILD if the error it expects stops happening,
// so weakening the union turns the whole typecheck lane red.
//
// Rendered, not just declared, so eslint sees them used and the file stays one test suite.
describe("Button · disabled while it holds the focus", () => {
  // A focused button that turns natively disabled loses the focus to <body> in Chrome (measured)
  // — and ~60 call sites disable the very button that was just pressed while its mutation runs.
  // jsdom does not move the focus, so the CONTRACT is what is pinned: while focused, the button is
  // unavailable by aria-disabled + a click guard, never by the native attribute.
  it("keeps the native attribute off while focused, and blocks activation", () => {
    const onClick = vi.fn();
    const { rerender } = render(<Button onClick={onClick}>Save</Button>);
    const btn = screen.getByRole("button", { name: "Save" });
    act(() => btn.focus());
    rerender(
      <Button onClick={onClick} disabled>
        Save
      </Button>,
    );
    expect(btn.hasAttribute("disabled")).toBe(false);
    expect(btn.getAttribute("aria-disabled")).toBe("true");
    fireEvent.click(btn);
    expect(onClick).not.toHaveBeenCalled();
  });

  it("also holds when the window has no focus and no focus event ever fired", () => {
    // Chrome, with another app in front: `.focus()` moves activeElement and fires nothing. The
    // button asks the document at render time, so it does not rely on the event (measured).
    const { rerender } = render(<Button onClick={() => {}}>Next</Button>);
    const btn = screen.getByRole("button", { name: "Next" });
    const active = vi.spyOn(document, "activeElement", "get").mockReturnValue(btn);
    rerender(
      <Button onClick={() => {}} disabled>
        Next
      </Button>,
    );
    expect(btn.hasAttribute("disabled")).toBe(false);
    expect(btn.getAttribute("aria-disabled")).toBe("true");
    active.mockRestore();
  });

  it("keeps a caller's aria-disabled focusable and inert to a click (unavailable with a reason)", () => {
    const onClick = vi.fn();
    render(
      <Button onClick={onClick} aria-disabled>
        Run all
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Run all" });
    expect(btn.hasAttribute("disabled")).toBe(false);
    expect(btn.getAttribute("aria-disabled")).toBe("true");
    fireEvent.click(btn);
    expect(onClick).not.toHaveBeenCalled();
  });

  it("is natively disabled again once the focus is elsewhere", () => {
    render(
      <Button onClick={() => {}} disabled>
        Save
      </Button>,
    );
    const btn = screen.getByRole("button", { name: "Save" });
    expect(btn.hasAttribute("disabled")).toBe(true);
  });
});

describe("Button accessible-name contract (type level)", () => {
  it("rejects a text-less button with no name, and accepts every named spelling", () => {
    render(
      <>
        {/* @ts-expect-error an icon with no children renders no text and no name */}
        <Button icon={<span />} data-testid="bad-c" />
        {/* @ts-expect-error the icon-only sizes moved to IconButton */}
        <Button size="icon" label="gone" />
        <Button icon={<span />} label="by label" />
        <Button icon={<span />} aria-label="by aria-label" />
        <Button icon={<span />} title="by title" />
        <Button>plain text needs none</Button>
        {/* @ts-expect-error a toggle states itself through `pressed`, which also paints it (B3) */}
        <Button aria-pressed>raw toggle</Button>
        <Button pressed>toggle</Button>
      </>,
    );
    expect(screen.getByRole("button", { name: "by label" })).toBeTruthy();
    expect(screen.getByRole("button", { name: "by aria-label" })).toBeTruthy();
    expect(screen.getByRole("button", { name: "by title" })).toBeTruthy();
  });
});