Add initial test files from lodash v4. (#4172)

* Install test dependencies.

* Add initial test files.

These files were created using a simplistic AST manipulator using `recast` to
preserve formatting. There's bound to be a huge chunk of errors, but this serves
as a good start. QUnit was replaced with Mocha, with ES2015 imports running via
`esm`.

As far as possible, QUnit-specific syntax has been replaced with Mocha's
`describe` and `it`, while the native Node.js `assert` module is used for
assertions. Files in the `test` directory ending in `.test.js` will be treated
as test files.

* Add initial passing files to test run.

test/curry-methods.js

@@ -0,0 +1,52 @@
+import assert from 'assert';
+import lodashStable from 'lodash';
+import { _, slice } from './utils.js';
+import curry from '../curry.js';
+
+describe('curry methods', function() {
+  lodashStable.each(['curry', 'curryRight'], function(methodName) {
+    var func = _[methodName],
+        fn = function(a, b) { return slice.call(arguments); },
+        isCurry = methodName == 'curry';
+
+    it('`_.' + methodName + '` should not error on functions with the same name as lodash methods', function() {
+      function run(a, b) {
+        return a + b;
+      }
+
+      var curried = func(run);
+
+      try {
+        var actual = curried(1)(2);
+      } catch (e) {}
+
+      assert.strictEqual(actual, 3);
+    });
+
+    it('`_.' + methodName + '` should work for function names that shadow those on `Object.prototype`', function() {
+      var curried = curry(function hasOwnProperty(a, b, c) {
+        return [a, b, c];
+      });
+
+      var expected = [1, 2, 3];
+
+      assert.deepStrictEqual(curried(1)(2)(3), expected);
+    });
+
+    it('`_.' + methodName + '` should work as an iteratee for methods like `_.map`', function() {
+      var array = [fn, fn, fn],
+          object = { 'a': fn, 'b': fn, 'c': fn };
+
+      lodashStable.each([array, object], function(collection) {
+        var curries = lodashStable.map(collection, func),
+            expected = lodashStable.map(collection, lodashStable.constant(isCurry ? ['a', 'b'] : ['b', 'a']));
+
+        var actual = lodashStable.map(curries, function(curried) {
+          return curried('a')('b');
+        });
+
+        assert.deepStrictEqual(actual, expected);
+      });
+    });
+  });
+});