Add complementary test case

packages/components/src/progress-bar/test/index.tsx

@@ -80,7 +80,7 @@ describe( 'ProgressBar', () => {
 		expect( screen.getByRole( 'progressbar' ) ).toHaveStyle( style );
 	} );
 
-	it( 'should expand to fit the parent when `hasUnconstrainedWidth` is true', () => {
+	it( 'should expand to fit the parent when `hasUnconstrainedWidth` is `true`', () => {
 		const { container } = render( <ProgressBar hasUnconstrainedWidth /> );
 
 		// eslint-disable-next-line testing-library/no-container, testing-library/no-node-access
@@ -90,4 +90,15 @@ describe( 'ProgressBar', () => {
 			'max-width': '160px',
 		} );
 	} );
+
+	it( 'should have a default `max-width` when `hasUnconstrainedWidth` is `false`', () => {
+		const { container } = render( <ProgressBar /> );
+
+		// eslint-disable-next-line testing-library/no-container, testing-library/no-node-access
+		const track = container.firstChild;
+
+		expect( track ).toHaveStyle( {
+			'max-width': '160px',
+		} );
+	} );
 } );