fix: shallow render with fragment at top lvl

.changeset/fast-rockets-admire.md

@@ -0,0 +1,5 @@
+---
+'preact-render-to-string': patch
+---
+
+Fix for shallow rendering incorrectly transforming Fragments into other nodes

src/pretty.js

@@ -103,7 +103,11 @@ function _renderToStringPretty(
 	// components
 	if (typeof nodeName === 'function') {
 		isComponent = true;
-		if (opts.shallow && (inner || opts.renderRootComponent === false)) {
+		if (
+			opts.shallow &&
+			(inner || opts.renderRootComponent === false) &&
+			nodeName !== Fragment
+		) {
 			nodeName = getComponentName(nodeName);
 		} else if (nodeName === Fragment) {
 			const children = [];

test/shallowRender.test.jsx

@@ -52,12 +52,26 @@ describe('shallowRender()', () => {
 		expect(Test).to.have.been.calledOnce;
 	});
 
-	it('should ignore Fragments', () => {
-		let rendered = shallowRender(
-			<Fragment>
-				<div>foo</div>
-			</Fragment>
-		);
-		expect(rendered).to.equal(`<div>foo</div>`);
+	describe('should ignore Fragments', () => {
+		it('passed directly', () => {
+			let rendered = shallowRender(
+				<Fragment>
+					<div>foo</div>
+				</Fragment>
+			);
+			expect(rendered).to.equal(`<div>foo</div>`);
+		});
+
+		it('passed from FC', () => {
+			const Test = () => (
+				<Fragment>
+					<div>foo</div>
+				</Fragment>
+			);
+
+			let rendered = shallowRender(<Test />);
+
+			expect(rendered).to.equal(`<div>foo</div>`);
+		});
 	});
 });