Test migration to jest by hand

Apparently using regular expressions is way easier.

test/toSnakeCase/toSnakeCase.js

@@ -0,0 +1,7 @@
+const toSnakeCase = str =>
+str &&
+str
+.match(/[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+/g)
+.map(x => x.toLowerCase())
+.join('_');
+module.exports = toSnakeCase;

test/toSnakeCase/toSnakeCase.test.js

@@ -0,0 +1,24 @@
+const expect = require('expect');
+const toSnakeCase = require('./toSnakeCase.js');
+
+
+  test('toSnakeCase is a Function', () => {
+  expect(toSnakeCase).toBeInstanceOf(Function);
+});
+  t.equal(toSnakeCase('camelCase'), 'camel_case', "toSnakeCase('camelCase') returns camel_case");
+  t.equal(toSnakeCase('some text'), 'some_text', "toSnakeCase('some text') returns some_text");
+  t.equal(toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'), 'some_mixed_string_with_spaces_underscores_and_hyphens', "toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens') returns some_mixed_string_with_spaces_underscores_and_hyphens");
+  t.equal(toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML'), 'i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html', "toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML') returns i_am_listening_to_fm_while_loading_different_url_on_my_browser_and_also_editing_some_xml_and_html");
+  t.equal(toSnakeCase(), undefined, 'toSnakeCase() returns undefined');
+  t.throws(() => toSnakeCase([]), 'toSnakeCase([]) throws an error');
+  t.throws(() => toSnakeCase({}), 'toSnakeCase({}) throws an error');
+  t.throws(() => toSnakeCase(123), 'toSnakeCase(123) throws an error');
+
+  let start = new Date().getTime();
+  toSnakeCase('IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML');
+  let end = new Date().getTime();
+  test('toSnakeCase(IAmListeningToFMWhileLoadingDifferentURLOnMyBrowserAndAlsoEditingSomeXMLAndHTML) takes less than 2s to run', () => {
+  expect((end - start) < 2000).toBeTruthy();
+});
+  
+