Add test coverage for custom search function.

__tests__/__snapshots__/index.spec.js.snap

@@ -569,9 +569,9 @@ exports[`<Select/> component <Select/> renders with custom search function 1`] =
         onKeyPress={[Function]}
         placeholder="Select..."
         readOnly={false}
-        size={9}
+        size={3}
         tabIndex="-1"
-        value=""
+        value="Zer"
       />
     </div>
     <div

__tests__/index.spec.js

@@ -1,5 +1,6 @@
 import React from 'react';
 import TestRenderer from 'react-test-renderer';
+import { LIB_NAME } from '../src/constants';
 
 import Select from '../src/index';
 
@@ -60,9 +61,25 @@ describe('<Select/> component', () => {
   });
 
   it('<Select/> renders with custom search function', () => {
-    const tree = selectWithProps(<Select {...props({ searchFn: () => {} })} />).toJSON();
+    const options = [
+      { id: 0, name: 'Zero' },
+      { id: 1, name: 'One' },
+      { id: 2, name: 'Two' },
+    ];
 
-    expect(tree).toMatchSnapshot();
+    const searchFn = ({ props, state }) => {
+      return props.options.filter(({ name }) => new RegExp(state.search).test(name) );
+    };
+
+    const component = selectWithProps(<Select {...props({ searchFn, options })} />);
+
+    const input = component.root.find(element => element.props.className === 'react-dropdown-select-input');
+
+    TestRenderer.act(() => input.props.onChange({ target: { value: 'Zer' } }));
+
+    expect(component.toTree().instance.state.search).toBe('Zer');
+    expect(component.toTree().instance.state.searchResults).toStrictEqual([{ id: 0, name: 'Zero'}])
+    expect(component.toJSON()).toMatchSnapshot();
   });
 
   it('<Select/> is disabled', () => {

src/index.js

@@ -382,6 +382,7 @@ export class Select extends Component {
     });
 
   handleKeyDown = (event) => {
+    console.log({ event });
     const args = {
       event,
       state: this.state,