fix: add unit tests

src/cell.test.jsx

@@ -0,0 +1,40 @@
+import { shallow } from 'enzyme';
+import React from 'react';
+
+import Cell from './cell';
+
+test('Cell > Adds default classNames', () => {
+  const wrapper = shallow(<Cell />, { disableLifecycleMethods: true });
+  const expected = 'mdc-layout-grid__cell';
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});
+
+test('Cell > Adds all classNames based on props', () => {
+  const ALIGN = 'bottom';
+  const CLASS_NAME = 'CLASS_NAME';
+  const COLUMNS = 12;
+  const DESKTOP = 12;
+  const PHONE = 4;
+  const TABLET = 8;
+  const wrapper = shallow(
+    <Cell
+      align={ALIGN}
+      className={CLASS_NAME}
+      columns={COLUMNS}
+      desktop={DESKTOP}
+      phone={PHONE}
+      tablet={TABLET}
+    />,
+    { disableLifecycleMethods: true },
+  );
+  const expected = `mdc-layout-grid__cell ${CLASS_NAME} mdc-layout-grid__cell--align-${ALIGN} ` +
+    `mdc-layout-grid__cell--span-${COLUMNS} mdc-layout-grid__cell--span-${DESKTOP}-desktop ` +
+    `mdc-layout-grid__cell--span-${PHONE}-phone mdc-layout-grid__cell--span-${TABLET}-tablet`;
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});

src/grid.test.jsx

@@ -0,0 +1,29 @@
+import { shallow } from 'enzyme';
+import React from 'react';
+
+import Grid from './grid';
+
+const CHILDREN = <p>CHILDREN</p>;
+
+test('Grid > Adds the default classNames', () => {
+  const wrapper = shallow(<Grid>{CHILDREN}</Grid>, { disableLifecycleMethods: true });
+  const expected = 'mdc-layout-grid';
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});
+
+test('Grid > Adds all classNames based on props', () => {
+  const ALIGN = 'left';
+  const CLASS_NAME = 'CLASS_NAME';
+  const wrapper = shallow(
+    <Grid align={ALIGN} className={CLASS_NAME}>{CHILDREN}</Grid>,
+    { disableLifecycleMethods: true },
+  );
+  const expected = `mdc-layout-grid mdc-layout-grid--align-${ALIGN} ${CLASS_NAME}`;
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});

src/row.test.jsx

@@ -0,0 +1,28 @@
+import { shallow } from 'enzyme';
+import React from 'react';
+
+import Row from './row';
+
+const CHILDREN = <p>CHILDREN</p>;
+
+test('Row > Adds the default classNames', () => {
+  const wrapper = shallow(<Row>{CHILDREN}</Row>, { disableLifecycleMethods: true });
+  const expected = 'mdc-layout-grid__inner';
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});
+
+test('Row > Adds all classNames based on props', () => {
+  const CLASS_NAME = 'CLASS_NAME';
+  const wrapper = shallow(
+    <Row className={CLASS_NAME}>{CHILDREN}</Row>,
+    { disableLifecycleMethods: true },
+  );
+  const expected = `mdc-layout-grid__inner ${CLASS_NAME}`;
+
+  const actual = wrapper.props().className;
+
+  expect(actual).toBe(expected);
+});