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479/**
* next/image component unit tests.
*
* Mirrors test cases from Next.js test/unit/next-image-new.test.ts and
* test/unit/next-image-get-img-props.test.ts, adapted for vinext's
* Image shim implementation.
*
* Tests SSR output, srcSet generation, getImageProps(), fill mode,
* priority, custom loader, and static image data handling.
*/
import { describe, it, expect } from "vitest";
import React from "react";
import ReactDOMServer from "react-dom/server";
import Image, { getImageProps, type StaticImageData } from "../packages/vinext/src/shims/image.js";
/** Helper: expected optimization URL matching what the image shim produces. */
function optUrl(src: string, w: number, q = 75): string {
return `/_vinext/image?url=${encodeURIComponent(src)}&w=${w}&q=${q}`;
}
/** Same as optUrl but with HTML entity encoding (for SSR output assertions). */
function optUrlHtml(src: string, w: number, q = 75): string {
return optUrl(src, w, q).replace(/&/g, "&");
}
// ─── SSR rendering ──────────────────────────────────────────────────────
describe("Image SSR rendering", () => {
it("renders a basic <img> tag with correct attributes", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "a nice image",
src: "/test.png",
width: 100,
height: 100,
}),
);
expect(html).toContain('alt="a nice image"');
// Local images are routed through the optimization endpoint
expect(html).toContain(`src="${optUrlHtml("/test.png", 100)}"`);
expect(html).toContain('width="100"');
expect(html).toContain('height="100"');
expect(html).toContain('decoding="async"');
expect(html).toContain('loading="lazy"');
expect(html).toContain('data-nimg="1"');
});
it("renders with priority (eager loading + fetchpriority)", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "priority image",
src: "/hero.png",
width: 800,
height: 600,
priority: true,
}),
);
expect(html).toContain('loading="eager"');
expect(html).toContain('fetchPriority="high"');
expect(html).not.toContain('loading="lazy"');
});
it("renders fill mode with absolute positioning", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "fill image",
src: "/bg.png",
fill: true,
}),
);
// Fill mode: no width/height attributes
expect(html).not.toMatch(/width="\d+"/);
expect(html).not.toMatch(/height="\d+"/);
// Fill adds position:absolute and 100% dimensions
expect(html).toContain("position:absolute");
expect(html).toContain("width:100%");
expect(html).toContain("height:100%");
expect(html).toContain('data-nimg="fill"');
// Fill defaults sizes to 100vw
expect(html).toContain('sizes="100vw"');
});
it("renders with custom sizes prop", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "sized",
src: "/img.png",
width: 500,
height: 300,
sizes: "(max-width: 768px) 100vw, 50vw",
}),
);
expect(html).toContain('sizes="(max-width: 768px) 100vw, 50vw"');
});
it("renders with blur placeholder styles", () => {
const blurDataURL = "data:image/png;base64,abc123";
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "blurry",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL,
}),
);
expect(html).toContain(`url(${blurDataURL})`);
expect(html).toContain("background-size:cover");
});
it("renders with custom loader", () => {
const loader = ({ src, width, quality }: { src: string; width: number; quality?: number }) =>
`https://cdn.example.com${src}?w=${width}&q=${quality || 75}`;
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "cdn image",
src: "/photo.jpg",
width: 200,
height: 150,
loader,
}),
);
expect(html).toContain('src="https://cdn.example.com/photo.jpg?w=200&q=75"');
});
it("renders StaticImageData (import result)", () => {
const staticImage: StaticImageData = {
src: "/_next/static/media/test.abc123.png",
width: 800,
height: 600,
blurDataURL: "data:image/png;base64,xyz",
};
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "static import",
src: staticImage,
placeholder: "blur",
}),
);
expect(html).toContain(`src="${optUrlHtml("/_next/static/media/test.abc123.png", 800)}"`);
expect(html).toContain('width="800"');
expect(html).toContain('height="600"');
expect(html).toContain("data:image/png;base64,xyz");
});
it("applies className and custom style", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "styled",
src: "/test.png",
width: 100,
height: 100,
className: "hero-img",
style: { borderRadius: "8px" },
}),
);
expect(html).toContain('class="hero-img"');
expect(html).toContain("border-radius:8px");
});
});
// ─── srcSet generation ──────────────────────────────────────────────────
describe("Image srcSet generation", () => {
it("generates srcSet for local images with width", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "test",
src: "/photo.png",
width: 500,
height: 400,
}),
);
// RESPONSIVE_WIDTHS = [640, 750, 828, 1080, 1200, 1920, 2048, 3840]
// Filter: widths <= 500 * 2 = 1000 → [640, 750, 828]
expect(html).toContain("srcSet");
expect(html).toContain(`${optUrlHtml("/photo.png", 640)} 640w`);
expect(html).toContain(`${optUrlHtml("/photo.png", 750)} 750w`);
expect(html).toContain(`${optUrlHtml("/photo.png", 828)} 828w`);
// Should not include widths > 1000
expect(html).not.toContain("1080w");
});
it("generates srcSet with all widths for large images", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "test",
src: "/large.png",
width: 2000,
height: 1500,
}),
);
// widths <= 4000: all of them
expect(html).toContain(`${optUrlHtml("/large.png", 640)} 640w`);
expect(html).toContain(`${optUrlHtml("/large.png", 3840)} 3840w`);
});
it("generates fallback srcSet for very small images", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "tiny",
src: "/icon.png",
width: 16,
height: 16,
}),
);
// widths <= 32: none of RESPONSIVE_WIDTHS qualify
// Falls back to single: optimized icon.png at 16w
expect(html).toContain(`${optUrlHtml("/icon.png", 16)} 16w`);
});
it("does not generate srcSet for fill mode", () => {
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "fill",
src: "/bg.png",
fill: true,
}),
);
// Fill mode: no srcSet (srcSet is only for local non-fill images with width)
expect(html).not.toContain("srcSet");
});
});
// ─── getImageProps ──────────────────────────────────────────────────────
describe("getImageProps", () => {
it("returns correct props for basic image", () => {
const { props } = getImageProps({
alt: "a nice desc",
src: "/test.png",
width: 100,
height: 200,
});
expect(props.alt).toBe("a nice desc");
expect(props.src).toBe(optUrl("/test.png", 100));
expect(props.width).toBe(100);
expect(props.height).toBe(200);
expect(props.loading).toBe("lazy");
expect(props.decoding).toBe("async");
expect((props as any)["data-nimg"]).toBe("1");
});
it("returns priority props", () => {
const { props } = getImageProps({
alt: "priority",
src: "/hero.png",
width: 800,
height: 600,
priority: true,
});
expect(props.loading).toBe("eager");
expect(props.fetchPriority).toBe("high");
});
it("returns fill mode props", () => {
const { props } = getImageProps({
alt: "fill",
src: "/bg.png",
fill: true,
});
expect(props.width).toBeUndefined();
expect(props.height).toBeUndefined();
expect(props.sizes).toBe("100vw");
expect((props as any)["data-nimg"]).toBe("fill");
expect((props.style as any)?.position).toBe("absolute");
expect((props.style as any)?.width).toBe("100%");
expect((props.style as any)?.height).toBe("100%");
});
it("returns custom loader URL", () => {
const loader = ({ src, width }: { src: string; width: number }) =>
`https://cdn.example.com${src}?w=${width}`;
const { props } = getImageProps({
alt: "cdn",
src: "/photo.jpg",
width: 300,
height: 200,
loader,
});
expect(props.src).toBe("https://cdn.example.com/photo.jpg?w=300");
});
it("returns blur placeholder styles", () => {
const { props } = getImageProps({
alt: "blur",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "data:image/png;base64,test",
});
expect((props.style as any)?.backgroundImage).toBe("url(data:image/png;base64,test)");
expect((props.style as any)?.backgroundSize).toBe("cover");
});
it("merges user style with default", () => {
const { props } = getImageProps({
alt: "styled",
src: "/test.png",
width: 100,
height: 100,
style: { maxWidth: "100%", height: "auto" },
});
expect((props.style as any)?.maxWidth).toBe("100%");
expect((props.style as any)?.height).toBe("auto");
});
it("passes through arbitrary props", () => {
const { props } = getImageProps({
alt: "test",
src: "/test.png",
width: 100,
height: 100,
id: "my-image",
} as any);
expect(props.id).toBe("my-image");
});
it("handles StaticImageData", () => {
const staticImage: StaticImageData = {
src: "/static/photo.png",
width: 1920,
height: 1080,
};
const { props } = getImageProps({
alt: "static",
src: staticImage,
});
expect(props.src).toBe(optUrl("/static/photo.png", 1920));
expect(props.width).toBe(1920);
expect(props.height).toBe(1080);
});
it("generates srcSet for local images", () => {
const { props } = getImageProps({
alt: "local",
src: "/photo.png",
width: 800,
height: 600,
});
expect(props.srcSet).toBeDefined();
expect(props.srcSet).toContain("/_vinext/image");
expect(props.srcSet).toContain("photo.png");
expect(props.srcSet).toContain("w");
});
it("handles loading=eager prop", () => {
const { props } = getImageProps({
alt: "eager",
src: "/test.png",
width: 100,
height: 100,
loading: "eager",
});
expect(props.loading).toBe("eager");
});
});
// ─── Security: blurDataURL CSS injection ────────────────────────────────
describe("blurDataURL CSS injection prevention", () => {
it("rejects blurDataURL with ) character (CSS url breakout)", () => {
const { props } = getImageProps({
alt: "malicious",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "data:x); color: red; background: url(",
});
// Should NOT have any backgroundImage — the malicious URL is rejected
expect((props.style as any)?.backgroundImage).toBeUndefined();
});
it("rejects blurDataURL with ; character (CSS property injection)", () => {
const { props } = getImageProps({
alt: "malicious",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "data:image/png;base64,abc); color: red; x: url(",
});
// The ; in data:image/png;base64 is fine, but ) breaks out of url()
expect((props.style as any)?.backgroundImage).toBeUndefined();
});
it("rejects blurDataURL with { character (CSS rule injection)", () => {
const { props } = getImageProps({
alt: "malicious",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "data:image/svg+xml,<svg>{</svg>",
});
expect((props.style as any)?.backgroundImage).toBeUndefined();
});
it("rejects blurDataURL that does not start with data:image/", () => {
const { props } = getImageProps({
alt: "malicious",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "javascript:alert(1)",
});
expect((props.style as any)?.backgroundImage).toBeUndefined();
});
it("accepts valid base64 blurDataURL", () => {
const { props } = getImageProps({
alt: "valid",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==",
});
expect((props.style as any)?.backgroundImage).toContain("data:image/png;base64,");
});
it("sanitizes blurDataURL in SSR rendering (Image component)", () => {
const maliciousURL = "data:x); color: red; background: url(";
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "malicious",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: maliciousURL,
}),
);
// Should NOT contain the malicious CSS injection
expect(html).not.toContain("color: red");
expect(html).not.toContain("color:red");
// Should NOT contain any background-image at all (blur was rejected)
expect(html).not.toContain("background-image");
});
it("renders valid blurDataURL in SSR", () => {
const validURL = "data:image/png;base64,abc123";
const html = ReactDOMServer.renderToString(
React.createElement(Image, {
alt: "valid blur",
src: "/photo.jpg",
width: 400,
height: 300,
placeholder: "blur",
blurDataURL: validURL,
}),
);
expect(html).toContain("background-image");
expect(html).toContain(validURL);
});
});