Add tests

packages/block-editor/src/components/line-height-control/test/index.js

@@ -0,0 +1,55 @@
+/**
+ * External dependencies
+ */
+import { fireEvent, render, screen } from '@testing-library/react';
+
+/**
+ * WordPress dependencies
+ */
+import { useState } from '@wordpress/element';
+import { UP, DOWN } from '@wordpress/keycodes';
+
+/**
+ * Internal dependencies
+ */
+import LineHeightControl from '../';
+import { BASE_DEFAULT_VALUE, STEP } from '../utils';
+
+const ControlledLineHeightControl = () => {
+	const [ value, setValue ] = useState();
+	return <LineHeightControl value={ value } onChange={ setValue } />;
+};
+
+describe( 'LineHeightControl', () => {
+	it( 'should immediately step up from the default value if up-arrowed from an unset state', () => {
+		render( <ControlledLineHeightControl /> );
+		const input = screen.getByRole( 'spinbutton' );
+		input.focus();
+		fireEvent.keyDown( input, { keyCode: UP } );
+		expect( input ).toHaveValue( BASE_DEFAULT_VALUE + STEP );
+	} );
+
+	it( 'should immediately step down from the default value if down-arrowed from an unset state', () => {
+		render( <ControlledLineHeightControl /> );
+		const input = screen.getByRole( 'spinbutton' );
+		input.focus();
+		fireEvent.keyDown( input, { keyCode: DOWN } );
+		expect( input ).toHaveValue( BASE_DEFAULT_VALUE - STEP );
+	} );
+
+	it( 'should immediately step up from the default value if spin button up was clicked from an unset state', () => {
+		render( <ControlledLineHeightControl /> );
+		const input = screen.getByRole( 'spinbutton' );
+		input.focus();
+		fireEvent.change( input, { target: { value: 0.1 } } ); // simulates click on spin button up
+		expect( input ).toHaveValue( BASE_DEFAULT_VALUE + STEP );
+	} );
+
+	it( 'should immediately step down from the default value if spin button down was clicked from an unset state', () => {
+		render( <ControlledLineHeightControl /> );
+		const input = screen.getByRole( 'spinbutton' );
+		input.focus();
+		fireEvent.change( input, { target: { value: 0 } } ); // simulates click on spin button down
+		expect( input ).toHaveValue( BASE_DEFAULT_VALUE - STEP );
+	} );
+} );