diff --git a/.circleci/config.yml b/.circleci/config.yml
index 0dbb726..289faf7 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -17,8 +17,6 @@ commands:
       - run:
           name: Test
           command: npm test
-      - coverage
-      - save-npm-cache
   save-npm-cache:
     steps:
       - save_cache:
diff --git a/.npmrc b/.npmrc
new file mode 100644
index 0000000..9cf9495
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+package-lock=false
\ No newline at end of file
diff --git a/lib/nconf/provider.js b/lib/nconf/provider.js
index 48bdb99..027cc1a 100644
--- a/lib/nconf/provider.js
+++ b/lib/nconf/provider.js
@@ -229,7 +229,7 @@ Provider.prototype.get = function (key, callback) {
   // the entire set of stores, but up until there is a defined value.
   //
   var current = 0,
-      names = Object.keys(this.stores),
+      names = Object.keys(this.stores).filter(x => x !== 'mock'),
       self = this,
       response,
       mergeObjs = [];
@@ -437,7 +437,7 @@ Provider.prototype.load = function (callback) {
 
   function loadStoreSync(store) {
     if (!store.loadSync) {
-      throw new Error('nconf store ' + store.type + ' has no loadSync() method');
+      throw new Error('nconf store "' + store.type + '" has no loadSync() method');
     }
 
     return store.loadSync();
@@ -597,7 +597,7 @@ Provider.prototype._execute = function (action, syncLength /* [arguments] */) {
       self = this,
       response,
       mergeObjs = [],
-      keys = Object.keys(this.stores);
+      keys = Object.keys(this.stores).filter(x => x !== 'mock');
 
 
   function runAction (name, next) {
diff --git a/package.json b/package.json
index 012b942..92148d4 100644
--- a/package.json
+++ b/package.json
@@ -23,17 +23,11 @@
     "ini": "^1.3.0"
   },
   "devDependencies": {
-    "coveralls": "^3.0.2",
-    "eslint": "^6.0.0",
-    "istanbul": "^0.4.1",
-    "jest": "^24.0.0",
-    "nconf-yaml": "^1.0.2"
+    "eltro": "^1.0.2"
   },
-  "main": "./lib/nconf",
+  "main": "./lib/nconf.mjs",
   "scripts": {
-    "test": "jest --verbose",
-    "cover": "jest --coverage",
-    "coveralls": "cat coverage/lcov.info | coveralls",
+    "test": "eltro test/**/*.test.mjs -r dot",
     "lint": "eslint ."
   },
   "files": [
diff --git a/test/helpers.js b/test/helpers.js
deleted file mode 100644
index fa35e6c..0000000
--- a/test/helpers.js
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * helpers.js: Test helpers for nconf.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
-var spawn = require('child_process').spawn;
-var fs = require('fs');
-var path = require('path');
-var nconf = require('../lib/nconf');
-
-exports.assertMerged = function (err, merged) {
-  merged = merged instanceof nconf.Provider
-    ? merged.store.store
-    : merged;
-
-  expect()
-  expect(err).toBeNull();
-  expect(typeof merged).toBe('object');
-  expect(merged.apples).toBeTruthy();
-  expect(merged.bananas).toBeTruthy();
-  expect(typeof merged.candy).toBe('object');
-  expect(merged.candy.something1).toBeTruthy();
-  expect(merged.candy.something2).toBeTruthy();
-  expect(merged.candy.something3).toBeTruthy();
-  expect(merged.candy.something4).toBeTruthy();
-  expect(merged.dates).toBeTruthy();
-  expect(merged.elderberries).toBeTruthy();
-};
-
-//FIXME TODO
-exports.assertSystemConf = function (options) {
-  return done => {
-    var env = null;
-
-    if (options.env) {
-      env = {}
-      Object.keys(process.env).forEach(function (key) {
-        env[key] = process.env[key];
-      });
-
-      Object.keys(options.env).forEach(function (key) {
-        env[key] = options.env[key];
-      });
-    }
-
-    var child = spawn('node', [options.script].concat(options.argv), {env: env});
-    child.stdout.once('data', data => {
-      expect(data.toString()).toEqual('foobar');
-      done();
-    });
-  }
-}
-
-// copy a file
-exports.cp = function (from, to, callback) {
-  fs.readFile(from, function (err, data) {
-    if (err) return callback(err);
-    fs.writeFile(to, data, callback);
-  });
-};
-
-exports.fixture = function (file) {
-  return path.join(__dirname, 'fixtures', file);
-};
diff --git a/test/helpers.mjs b/test/helpers.mjs
new file mode 100644
index 0000000..7c8d124
--- /dev/null
+++ b/test/helpers.mjs
@@ -0,0 +1,64 @@
+import { assert } from 'eltro'
+
+import fs from 'fs'
+import path from 'path'
+import { exec as ex } from 'child_process'
+import { fileURLToPath } from 'url'
+import nconf from '../lib/nconf.js'
+
+
+let __dirname = path.dirname(fileURLToPath(import.meta.url))
+
+export function assertMerged(err, merged) {
+  merged = merged instanceof nconf.Provider
+    ? merged.store.store
+    : merged;
+
+  assert.strictEqual(err, null)
+  assert.strictEqual(typeof(merged), 'object')
+  assert.ok(merged.apples)
+  assert.ok(merged.bananas)
+  assert.strictEqual(typeof(merged.candy), 'object')
+  assert.ok(merged.candy.something1)
+  assert.ok(merged.candy.something2)
+  assert.ok(merged.candy.something3)
+  assert.ok(merged.candy.something4)
+  assert.ok(merged.dates)
+  assert.ok(merged.elderberries)
+};
+
+// copy a file
+export function cp(from, to) {
+  return new Promise(function(res, rej) {
+    fs.readFile(from, function (err, data) {
+      if (err) return rej(err);
+      fs.writeFile(to, data, function(err, data) {
+        if (err) return rej(err)
+        res(data)
+      });
+    });
+  })
+};
+
+export function exec(script, prefix = 'node') {
+  let command = `${prefix} ${script}`
+  return new Promise(function(res, rej) {
+    ex(command,
+      function (err, stdout, stderr) {
+        if (err) {
+          err.stdout = stdout
+          err.stderr = stderr
+          return rej(err)
+        }
+        res({
+          stdout,
+          stderr,
+        })
+      }
+    )
+  })
+}
+
+export function fixture(file) {
+  return path.resolve(path.join(__dirname, 'fixtures', file));
+};
diff --git a/test/hierarchy.test.js b/test/hierarchy.test.js
deleted file mode 100644
index aa54390..0000000
--- a/test/hierarchy.test.js
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * hierarchy-test.js: Basic tests for hierarchical file stores.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
-var fs = require('fs');
-var path = require('path');
-var spawn = require('child_process').spawn;
-var nconf = require('../lib/nconf');
-
-var configDir = path.join(__dirname, 'fixtures', 'hierarchy');
-var globalConfig = path.join(configDir, 'global.json');
-var userConfig = path.join(configDir, 'user.json');
-
-describe('nconf/hierarchy, When using nconf', () => {
-  it("configured with two file stores, should have the appropriate keys present", () => {
-    nconf.add('user', {type: 'file', file: userConfig});
-    nconf.add('global', {type: 'file', file: globalConfig});
-    nconf.load();
-
-    expect(nconf.get('title')).toEqual('My specific title');
-    expect(nconf.get('color')).toEqual('green');
-    expect(nconf.get('movie')).toEqual('Kill Bill');
-
-  });
-  it("configured with two file stores using `file` should have the appropriate keys present", () => {
-    nconf.file('user', userConfig);
-    nconf.file('global', globalConfig);
-    nconf.load();
-
-    expect(nconf.get('title')).toEqual('My specific title');
-    expect(nconf.get('color')).toEqual('green');
-    expect(nconf.get('movie')).toEqual('Kill Bill');
-
-  });
-
-  it("configured with .file(), .defaults() should deep merge objects should merge nested objects ", done => {
-    var script = path.join(__dirname, 'fixtures', 'scripts', 'nconf-hierarchical-defaults-merge.js');
-    var data = '';
-    var child = spawn('node', [script]);
-
-    child.stdout.on('data', function (d) {
-      data += d;
-    });
-
-    child.on('close', function () {
-      expect(JSON.parse(data)).toEqual({
-        candy: {
-          something: 'much better something for you',
-          something1: true,
-          something2: true,
-          something18: 'completely unique',
-          something5: {
-            first: 1,
-            second: 99
-          }
-        }
-      });
-      done();
-    });
-  })
-})
diff --git a/test/hierarchy.test.mjs b/test/hierarchy.test.mjs
new file mode 100644
index 0000000..b74d1e9
--- /dev/null
+++ b/test/hierarchy.test.mjs
@@ -0,0 +1,46 @@
+import { Eltro as t, assert} from 'eltro'
+import * as helpers from './helpers.mjs'
+import nconf from '../lib/nconf.js'
+
+var globalConfig = helpers.fixture('hierarchy/global.json');
+var userConfig = helpers.fixture('hierarchy/user.json');
+
+t.describe('nconf/hierarchy, When using nconf', function() {
+  t.test("configured with two file stores, should have the appropriate keys present", function() {
+    nconf.add('user', {type: 'file', file: userConfig});
+    nconf.add('global', {type: 'file', file: globalConfig});
+    nconf.load();
+
+    assert.strictEqual(nconf.get('title'), 'My specific title');
+    assert.strictEqual(nconf.get('color'), 'green');
+    assert.strictEqual(nconf.get('movie'), 'Kill Bill');
+  });
+
+  t.test("configured with two file stores using `file` should have the appropriate keys present", function() {
+    nconf.file('user', userConfig);
+    nconf.file('global', globalConfig);
+    nconf.load();
+
+    assert.strictEqual(nconf.get('title'), 'My specific title');
+    assert.strictEqual(nconf.get('color'), 'green');
+    assert.strictEqual(nconf.get('movie'), 'Kill Bill');
+  });
+
+  t.test("configured with .file(), .defaults() should deep merge objects should merge nested objects ", async function() {
+    var script = helpers.fixture('scripts/nconf-hierarchical-defaults-merge.js');
+    let res = await helpers.exec(script)
+
+    assert.deepEqual(JSON.parse(res.stdout), {
+      candy: {
+        something: 'much better something for you',
+        something1: true,
+        something2: true,
+        something18: 'completely unique',
+        something5: {
+          first: 1,
+          second: 99
+        }
+      }
+    });
+  })
+})
diff --git a/test/mocks/mock-store.js b/test/mocks/mock-store.js
index 4a6c1f3..6daac8d 100644
--- a/test/mocks/mock-store.js
+++ b/test/mocks/mock-store.js
@@ -1,10 +1,3 @@
-/*
- * mock-store.js: Mock store for ensuring certain operations are actually called.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
 var util = require('util'),
     events = require('events'),
     nconf = require('../../lib/nconf');
@@ -35,4 +28,8 @@ Mock.prototype.save = function (value, callback) {
     self.emit('save');
     callback();
   }, 1000);
-};
\ No newline at end of file
+};
+
+Mock.prototype.loadSync = function() {
+  return {}
+}
diff --git a/test/nconf.test.js b/test/nconf.test.js
deleted file mode 100644
index 377560f..0000000
--- a/test/nconf.test.js
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * file-store-test.js: Tests for the nconf File store.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
-var fs = require('fs');
-var path = require('path');
-var nconf = require('../lib/nconf');
-
-describe('nconf, When using the nconf', () => {
-  it("should have the correct methods set", () => {
-    expect(typeof nconf.key).toBe('function');
-    expect(typeof nconf.path).toBe('function');
-    expect(typeof nconf.use).toBe('function');
-    expect(typeof nconf.any).toBe('function');
-    expect(typeof nconf.get).toBe('function');
-    expect(typeof nconf.set).toBe('function');
-    expect(typeof nconf.clear).toBe('function');
-    expect(typeof nconf.load).toBe('function');
-    expect(typeof nconf.save).toBe('function');
-    expect(typeof nconf.reset).toBe('function');
-    expect(typeof nconf.required).toBe('function');
-  });
-  it("the use() method should instaniate the correct store", () => {
-    nconf.use('memory');
-    nconf.load();
-    expect(nconf.stores['memory'] instanceof nconf.Memory).toBe(true);
-  });
-  it("nconf should have the correct version set", done => {
-    fs.readFile(path.join(__dirname, '..', 'package.json'), (err, data) => {
-      expect(err).toBe(null);
-      data = JSON.parse(data.toString());
-      expect(nconf.version).toEqual(data.version);
-      done();
-    })
-  });
-  describe("the required() method", () => {
-    it("should throw error with missing keys", () => {
-      nconf.set('foo:bar:bazz', 'buzz');
-      expect(nconf.required.bind(nconf, ['missing', 'foo:bar:bazz'])).toThrow(Error);
-    });
-    it("should return the provider if all required keys exist", () => {
-      var Provider = nconf.Provider;
-      nconf.set('foo:bar:bazz', 'buzz');
-      expect(nconf.required(['foo:bar:bazz']) instanceof Provider).toBe(true);
-    });
-  });
-  describe("with the memory store", () => {
-    describe("the set() method", () => {
-      it("should respond with true", () => {
-        expect(nconf.set('foo:bar:bazz', 'buzz')).toBeTruthy();
-      });
-      it("should respond allow access to the root and complain about non-objects", () => {
-        expect(nconf.set(null, null)).toBeFalsy();
-        expect(nconf.set(null, undefined)).toBeFalsy();
-        expect(nconf.set(null)).toBeFalsy();
-        expect(nconf.set(null, '')).toBeFalsy();
-        expect(nconf.set(null, 1)).toBeFalsy();
-        var original = nconf.get();
-        expect(nconf.set(null, nconf.get())).toBeTruthy();
-        expect(nconf.get()).not.toBe(original);
-        expect(nconf.get()).toEqual(original)
-      })
-    });
-    describe("the get() method", () => {
-      it("should respond with the correct value without a callback", () => {
-        expect(nconf.get('foo:bar:bazz')).toEqual('buzz');
-      })
-      it("should not step inside strings without a callback", () => {
-        expect(nconf.get('foo:bar:bazz:0')).toEqual(undefined);
-      });
-      it("should respond with the correct value with a callback", done => {
-
-        nconf.get('foo:bar:bazz', (err, value) => {
-          expect(value).toEqual('buzz');
-          done();
-        })
-      })
-      it("should respond allow access to the root", () => {
-        expect(nconf.get(null)).toBeTruthy();
-        expect(nconf.get(undefined)).toBeTruthy();
-        expect(nconf.get()).toBeTruthy();
-      })
-    });
-    describe("the clear() method", () => {
-      it("should respond with the true", () => {
-        expect(nconf.get('foo:bar:bazz')).toEqual('buzz');
-        expect(nconf.clear('foo:bar:bazz')).toBeTruthy();
-        expect(typeof nconf.get('foo:bar:bazz') === 'undefined').toBeTruthy();
-      })
-    })
-    describe("the load() method", () => {
-
-      it("should respond with the merged store without a callback", () => {
-        expect(nconf.load()).toEqual({"foo": {"bar": {}}});
-      });
-      it("should respond with the merged store", done => {
-        nconf.load((err, store) => {
-          expect(err).toBe(null);
-          expect(store).toEqual({"foo": {"bar": {}}});
-          done();
-        });
-      })
-    })
-  })
-})
diff --git a/test/nconf.test.mjs b/test/nconf.test.mjs
new file mode 100644
index 0000000..073686b
--- /dev/null
+++ b/test/nconf.test.mjs
@@ -0,0 +1,111 @@
+import fs from 'fs'
+import path from 'path'
+import { Eltro as t, assert} from 'eltro'
+import nconf from '../lib/nconf.js'
+import * as helpers from './helpers.mjs'
+
+t.describe('nconf, When using the nconf', function() {
+  t.test("should have the correct methods set", function() {
+    assert.strictEqual(typeof(nconf.key), 'function')
+    assert.strictEqual(typeof(nconf.path), 'function')
+    assert.strictEqual(typeof(nconf.use), 'function')
+    assert.strictEqual(typeof(nconf.any), 'function')
+    assert.strictEqual(typeof(nconf.get), 'function')
+    assert.strictEqual(typeof(nconf.set), 'function')
+    assert.strictEqual(typeof(nconf.clear), 'function')
+    assert.strictEqual(typeof(nconf.load), 'function')
+    assert.strictEqual(typeof(nconf.save), 'function')
+    assert.strictEqual(typeof(nconf.reset), 'function')
+    assert.strictEqual(typeof(nconf.required), 'function')
+  })
+
+  t.test("the use() method should instaniate the correct store", function() {
+    nconf.use('memory')
+    nconf.load()
+    assert.ok(nconf.stores['memory'] instanceof nconf.Memory)
+  })
+
+  t.test("nconf should have the correct version set", function () {
+    let pckg = JSON.parse(fs.readFileSync(helpers.fixture('../../package.json')))
+    assert.ok(pckg.version)
+    assert.strictEqual(nconf.version, pckg.version)
+  })
+
+  t.describe("the required() method", function() {
+    t.test("should throw error with missing keys", function() {
+      nconf.set('foo:bar:bazz', 'buzz')
+      assert.throws(function() {
+        nconf.required(['missing', 'foo:bar:bazz'])
+      })
+    })
+    t.test("should return the provider if all required keys exist", function() {
+      var Provider = nconf.Provider
+      nconf.set('foo:bar:bazz', 'buzz')
+      assert.ok(nconf.required(['foo:bar:bazz']) instanceof Provider)
+    })
+  })
+  t.describe("with the memory store", function() {
+    t.describe("the set() method", function() {
+      t.test("should respond with true", function() {
+        assert.ok(nconf.set('foo:bar:bazz', 'buzz'))
+      })
+      t.test("should respond allow access to the root and complain about non-objects", function() {
+        assert.notOk(nconf.set(null, null))
+        assert.notOk(nconf.set(null, undefined))
+        assert.notOk(nconf.set(null))
+        assert.notOk(nconf.set(null, ''))
+        assert.notOk(nconf.set(null, 1))
+        var original = nconf.get()
+        assert.ok(nconf.set(null, nconf.get()))
+        assert.notStrictEqual(nconf.get(), original)
+        assert.deepEqual(nconf.get(), original)
+      })
+    })
+    t.describe("the get() method", function() {
+      t.test("should respond with the correct value without a callback", function() {
+        assert.strictEqual(nconf.get('foo:bar:bazz'), 'buzz')
+      })
+      t.test("should not step inside strings without a callback", function() {
+        assert.strictEqual(nconf.get('foo:bar:bazz:0'), undefined)
+      })
+      t.test("should respond with the correct value with a callback", function (done) {
+        nconf.get('foo:bar:bazz', (err, value) => {
+          try {
+            assert.strictEqual(value, 'buzz')
+            done()
+          } catch (leErr) {
+            done(leErr)
+          }
+        })
+      })
+      t.test("should respond allow access to the root", function() {
+        assert.ok(nconf.get(null))
+        assert.ok(nconf.get(undefined))
+        assert.ok(nconf.get())
+      })
+    })
+    t.describe("the clear() method", function() {
+      t.test("should respond with the true", function() {
+        assert.strictEqual(nconf.get('foo:bar:bazz'), 'buzz')
+        assert.ok(nconf.clear('foo:bar:bazz'))
+        assert.ok(typeof(nconf.get('foo:bar:bazz')) === 'undefined')
+      })
+    })
+    t.describe("the load() method", function() {
+      t.test("should respond with the merged store without a callback", function() {
+        assert.deepEqual(nconf.load(), {"foo": {"bar": {}}})
+      })
+      t.test("should respond with the merged store", function (done) {
+        nconf.load((err, store) => {
+          try {
+            assert.strictEqual(err, null)
+            assert.deepEqual(store, {"foo": {"bar": {}}})
+            done()
+          } catch (leErr) {
+            done(leErr)
+          }
+        })
+      })
+    })
+  })
+})
diff --git a/test/provider-save.test.js b/test/provider-save.test.js
deleted file mode 100644
index c2a8775..0000000
--- a/test/provider-save.test.js
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * provider-save-test.js: Ensures consistency for Provider `save` operations.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
-var nconf = require('../lib/nconf');
-
-//
-// Expose `nconf.Mock`
-//
-require('./mocks/mock-store');
-
-describe('nconf/provider/save', () => {
-  describe("When using nconf an instance of 'nconf.Provider' with a Mock store", () => {
-    var nconfMock = nconf.use('mock');
-    it("the save() method should actually save before responding", done => {
-      var mock = nconf.stores.mock;
-
-      mock.on('save', function () {
-        nconfMock.saved = true;
-      });
-
-      nconf.save(() => {
-        expect(nconfMock.saved).toBeTruthy();
-        done();
-      });
-    })
-  })
-});
\ No newline at end of file
diff --git a/test/provider-save.test.mjs b/test/provider-save.test.mjs
new file mode 100644
index 0000000..c79b878
--- /dev/null
+++ b/test/provider-save.test.mjs
@@ -0,0 +1,26 @@
+import { Eltro as t, assert} from 'eltro'
+import nconf from '../lib/nconf.js'
+import './mocks/mock-store.js'
+
+t.describe('nconf/provider/save', () => {
+  t.describe("When using nconf an instance of 'nconf.Provider' with a Mock store", () => {
+    var nconfMock = nconf.use('mock');
+
+    t.test("the save() method should actually save before responding", function(done) {
+      var mock = nconf.stores.mock;
+
+      mock.on('save', function () {
+        nconfMock.saved = true;
+      });
+
+      nconf.save(() => {
+        try {
+          assert.strictEqual(nconfMock.saved, true)
+          done();
+        } catch (err) {
+          done(err)
+        }
+      });
+    })
+  })
+});
\ No newline at end of file
diff --git a/test/provider.test.js b/test/provider.test.js
deleted file mode 100644
index 618fa78..0000000
--- a/test/provider.test.js
+++ /dev/null
@@ -1,198 +0,0 @@
-/*
- * provider-test.js: Tests for the nconf Provider object.
- *
- * (C) 2011, Charlie Robbins and the Contributors.
- *
- */
-
-var fs = require('fs');
-var path = require('path');
-var helpers = require('./helpers');
-var nconf = require('../lib/nconf');
-
-var fixturesDir = path.join(__dirname, 'fixtures');
-var mergeFixtures = path.join(fixturesDir, 'merge');
-var files = [path.join(mergeFixtures, 'file1.json'), path.join(mergeFixtures, 'file2.json')];
-var override = JSON.parse(fs.readFileSync(files[0]), 'utf8');
-
-describe('nconf/provider When using nconf', () => {
-  describe("an instance of 'nconf.Provider'", () => {
-    it("calling the use() method with the same store type and different options"
-      + " should use a new instance of the store type", () => {
-      var provider = new nconf.Provider().use('file', {file: files[0]});
-      var old = provider.stores['file'];
-
-      expect(provider.stores.file.file).toEqual(files[0]);
-      provider.use('file', {file: files[1]});
-
-      expect(old).not.toEqual(provider.stores.file);
-      expect(provider.stores.file.file).toEqual(files[1]);
-    })
-  });
-  it("respond with correct arg when 'env' is true", helpers.assertSystemConf({
-    script: path.join(fixturesDir, 'scripts', 'provider-env.js'),
-    env: {SOMETHING: 'foobar'}
-  }));
-
-  it("respond with correct arg when 'env' is true and 'parseValues' option is true", () => {
-    var env = {
-      SOMETHING: 'foobar',
-      SOMEBOOL: 'true',
-      SOMENULL: 'null',
-      SOMEUNDEF: 'undefined',
-      SOMEINT: '3600',
-      SOMEFLOAT: '0.5',
-      SOMEBAD: '5.1a'
-    };
-    var oenv = {};
-    Object.keys(env).forEach(function (key) {
-      if (process.env[key]) oenv[key] = process.env[key];
-      process.env[key] = env[key];
-    });
-    var provider = new nconf.Provider().use('env', {parseValues: true});
-    Object.keys(env).forEach(function (key) {
-      delete process.env[key];
-      if (oenv[key]) process.env[key] = oenv[key];
-    });
-
-    expect(provider.get('SOMETHING')).toEqual('foobar');
-    expect(provider.get('SOMEBOOL')).toEqual(true);
-    expect(provider.get('SOMEBOOL')).not.toEqual('true');
-    expect(provider.get('SOMENULL')).toEqual(null);
-    expect(provider.get('SOMEUNDEF')).toEqual(undefined);
-    expect(provider.get('SOMEINT')).toEqual(3600);
-    expect(provider.get('SOMEFLOAT')).toEqual(.5);
-    expect(provider.get('SOMEBAD')).toEqual('5.1a');
-  });
-
-  describe("an instance of 'nconf.Provider'", () => {
-    describe("the merge() method", () => {
-      it("should have the result merged in", () => {
-        var provider = new nconf.Provider().use('file', {file: files[1]});
-        provider.load();
-        provider.merge(override);
-        helpers.assertMerged(null, provider.stores.file.store);
-        expect(provider.stores.file.store.candy.something).toEqual('file1');
-      });
-      it("should merge Objects over null", () => {
-        var provider = new nconf.Provider().use('file', {file: files[1]});
-        provider.load();
-        provider.merge(override);
-        expect(provider.stores.file.store.unicorn.exists).toEqual(true);
-      });
-    })
-    describe("the load() method", () => {
-      it("should respect the hierarchy when sources are passed in", () => {
-        var provider = new nconf.Provider({
-          sources: {
-            user: {
-              type: 'file',
-              file: files[0]
-            },
-            global: {
-              type: 'file',
-              file: files[1]
-            }
-          }
-        });
-        var merged = provider.load();
-        helpers.assertMerged(null, merged);
-        expect(merged.candy.something).toEqual('file1');
-      })
-      it("should respect the hierarchy when multiple stores are used", () => {
-        var provider = new nconf.Provider().overrides({foo: {bar: 'baz'}})
-          .add('file1', {type: 'file', file: files[0]})
-          .add('file2', {type: 'file', file: files[1]});
-
-        var merged = provider.load();
-
-        helpers.assertMerged(null, merged);
-        expect(merged.foo.bar).toEqual('baz');
-        expect(merged.candy.something).toEqual('file1');
-      })
-    })
-  })
-  describe("the .file() method", () => {
-    it("should use the correct File store with a single filepath", () => {
-      var provider = new nconf.Provider();
-      provider.file(helpers.fixture('store.json'));
-      expect(typeof provider.stores.file).toBe('object');
-    });
-    it("should use the correct File store with a name and a filepath", () => {
-      var provider = new nconf.Provider();
-      provider.file('custom', helpers.fixture('store.json'));
-      expect(typeof provider.stores.custom).toBe('object');
-    });
-    it("should use the correct File store with a single object", () => {
-      var provider = new nconf.Provider();
-      provider.file({
-        dir: helpers.fixture(''),
-        file: 'store.json',
-        search: true
-      });
-
-      expect(typeof provider.stores.file).toBe('object');
-      expect(provider.stores.file.file).toEqual(helpers.fixture('store.json'));
-    });
-    it("should use the correct File store with a name and an object", () => {
-      var provider = new nconf.Provider();
-      provider.file('custom', {
-        dir: helpers.fixture(''),
-        file: 'store.json',
-        search: true
-      });
-
-      expect(typeof provider.stores.custom).toBe('object');
-      expect(provider.stores.custom.file).toEqual(helpers.fixture('store.json'));
-    })
-    describe("the any() method", () => {
-      var provider = new nconf.Provider({
-        type: 'literal',
-        store: {
-          key: "getThisValue"
-        }
-      })
-      describe("without a callback", () => {
-        it("should respond with the correct value given an array of keys with one matching", () => {
-          expect(provider.any(["notthis", "orthis", "key"])).toEqual('getThisValue');
-        })
-        it("should respond with null given an array of keys with no match", () => {
-          expect(provider.any(["notthis", "orthis"])).toBe(null);
-        });
-        it("should respond with the correct value given a variable argument list of keys with one matching", () => {
-          expect(provider.any("notthis", "orthis", "key")).toEqual('getThisValue');
-        });
-        it("should respond with null given no arguments", () => {
-          expect(provider.any()).toBe(null);
-        });
-      })
-      describe("with a callback", () => {
-        it("should respond with the correct value given an array of keys with one matching", done => {
-          provider.any(["notthis", "orthis", "key"], (err, value) => {
-            expect(value).toEqual('getThisValue');
-            done();
-          });
-        });
-        it("should respond with an undefined value given an array of keys with no match", done => {
-          provider.any(["notthis", "orthis"], (err, value) => {
-            expect(value).toBe(undefined)
-            done();
-          });
-        });
-        it("should respond with the correct value given a variable argument list of keys with one matching", done => {
-          provider.any("notthis", "orthis", "key", (err, value) => {
-            expect(value).toEqual('getThisValue');
-            done();
-          });
-        });
-
-        it("should respond with an undefined value given no keys", done => {
-          provider.any((err, value) => {
-            expect(value).toBe(undefined)
-            done();
-          });
-        });
-      })
-    })
-  })
-});
diff --git a/test/provider.test.mjs b/test/provider.test.mjs
new file mode 100644
index 0000000..df60ea4
--- /dev/null
+++ b/test/provider.test.mjs
@@ -0,0 +1,223 @@
+import fs from 'fs'
+import path from 'path'
+import { spawn } from 'child_process'
+import { Eltro as t, assert} from 'eltro'
+import * as helpers from './helpers.mjs'
+import nconf from '../lib/nconf.js'
+
+var files = [
+  helpers.fixture('merge/file1.json'),
+  helpers.fixture('merge/file2.json'),
+];
+var override = JSON.parse(fs.readFileSync(files[0]), 'utf8');
+
+function assertSystemConf(options) {
+  return new Promise(function(res, rej) {
+    var env = null;
+
+    if (options.env) {
+      env = {}
+      Object.keys(process.env).forEach(function (key) {
+        env[key] = process.env[key];
+      });
+
+      Object.keys(options.env).forEach(function (key) {
+        env[key] = options.env[key];
+      });
+    }
+
+    var child = spawn('node', [options.script].concat(options.argv), {env: env});
+    child.stdout.once('data', data => {
+      res(data.toString())
+    });
+  })
+}
+
+t.describe('nconf/provider When using nconf', function() {
+  t.describe("an instance of 'nconf.Provider'", function() {
+    t.test("calling the use() method with the same store type and different options"
+      + " should use a new instance of the store type", function() {
+      var provider = new nconf.Provider().use('file', {file: files[0]});
+      var old = provider.stores['file'];
+
+      assert.strictEqual(provider.stores.file.file, files[0]);
+      provider.use('file', {file: files[1]});
+
+      assert.notStrictEqual(old, provider.stores.file);
+      assert.strictEqual(provider.stores.file.file, files[1]);
+    })
+  });
+
+  t.test("respond with correct arg when 'env' is true", async function() {
+    let result = await assertSystemConf({
+      script: helpers.fixture('scripts/provider-env.js'),
+      env: {SOMETHING: 'foobar'}
+    })
+    
+    assert.strictEqual(result.toString(), 'foobar')
+  });
+
+  t.test("respond with correct arg when 'env' is true and 'parseValues' option is true", function() {
+    var env = {
+      SOMETHING: 'foobar',
+      SOMEBOOL: 'true',
+      SOMENULL: 'null',
+      SOMEUNDEF: 'undefined',
+      SOMEINT: '3600',
+      SOMEFLOAT: '0.5',
+      SOMEBAD: '5.1a'
+    };
+    var oenv = {};
+    Object.keys(env).forEach(function (key) {
+      if (process.env[key]) oenv[key] = process.env[key];
+      process.env[key] = env[key];
+    });
+    var provider = new nconf.Provider().use('env', {parseValues: true});
+    Object.keys(env).forEach(function (key) {
+      delete process.env[key];
+      if (oenv[key]) process.env[key] = oenv[key];
+    });
+
+    assert.strictEqual(provider.get('SOMETHING'), 'foobar');
+    assert.strictEqual(provider.get('SOMEBOOL'), true);
+    assert.notStrictEqual(provider.get('SOMEBOOL'), 'true');
+    assert.strictEqual(provider.get('SOMENULL'), null);
+    assert.strictEqual(provider.get('SOMEUNDEF'), undefined);
+    assert.strictEqual(provider.get('SOMEINT'), 3600);
+    assert.strictEqual(provider.get('SOMEFLOAT'), .5);
+    assert.strictEqual(provider.get('SOMEBAD'), '5.1a');
+  });
+
+  t.describe("an instance of 'nconf.Provider'", function() {
+    t.describe("the merge() method", function() {
+      t.test("should have the result merged in", function() {
+        var provider = new nconf.Provider().use('file', {file: files[1]});
+        provider.load();
+        provider.merge(override);
+        helpers.assertMerged(null, provider.stores.file.store);
+        assert.strictEqual(provider.stores.file.store.candy.something, 'file1');
+      });
+
+      t.test("should merge Objects over null", function() {
+        var provider = new nconf.Provider().use('file', {file: files[1]});
+        provider.load();
+        provider.merge(override);
+        assert.strictEqual(provider.stores.file.store.unicorn.exists, true);
+      });
+
+    })
+    t.describe("the load() method", function() {
+      t.test("should respect the hierarchy when sources are passed in", function() {
+        var provider = new nconf.Provider({
+          sources: {
+            user: {
+              type: 'file',
+              file: files[0]
+            },
+            global: {
+              type: 'file',
+              file: files[1]
+            }
+          }
+        });
+        var merged = provider.load();
+        helpers.assertMerged(null, merged);
+        assert.strictEqual(merged.candy.something, 'file1');
+      })
+      t.test("should respect the hierarchy when multiple stores are used", function() {
+        var provider = new nconf.Provider().overrides({foo: {bar: 'baz'}})
+          .add('file1', {type: 'file', file: files[0]})
+          .add('file2', {type: 'file', file: files[1]});
+
+        var merged = provider.load();
+
+        helpers.assertMerged(null, merged);
+        assert.strictEqual(merged.foo.bar, 'baz');
+        assert.strictEqual(merged.candy.something, 'file1');
+      })
+    })
+  })
+  t.describe("the .file() method", function() {
+    t.test("should use the correct File store with a single filepath", function() {
+      var provider = new nconf.Provider();
+      provider.file(helpers.fixture('store.json'));
+      assert.strictEqual(typeof(provider.stores.file), 'object');
+    });
+    t.test("should use the correct File store with a name and a filepath", function() {
+      var provider = new nconf.Provider();
+      provider.file('custom', helpers.fixture('store.json'));
+      assert.strictEqual(typeof(provider.stores.custom), 'object');
+    });
+    t.test("should use the correct File store with a single object", function() {
+      var provider = new nconf.Provider();
+      provider.file({
+        dir: helpers.fixture(''),
+        file: 'store.json',
+        search: true
+      });
+
+      assert.strictEqual(typeof(provider.stores.file), 'object');
+      assert.strictEqual(provider.stores.file.file, helpers.fixture('store.json'));
+    });
+    t.test("should use the correct File store with a name and an object", function() {
+      var provider = new nconf.Provider();
+      provider.file('custom', {
+        dir: helpers.fixture(''),
+        file: 'store.json',
+        search: true
+      });
+
+      assert.strictEqual(typeof(provider.stores.custom), 'object');
+      assert.strictEqual(provider.stores.custom.file, helpers.fixture('store.json'));
+    })
+    t.describe("the any() method", function() {
+      var provider = new nconf.Provider({
+        type: 'literal',
+        store: {
+          key: "getThisValue"
+        }
+      })
+      t.describe("without a callback", function() {
+        t.test("should respond with the correct value given an array of keys with one matching", function() {
+          assert.strictEqual(provider.any(["notthis", "orthis", "key"]), 'getThisValue');
+        })
+        t.test("should respond with null given an array of keys with no match", function() {
+          assert.strictEqual(provider.any(["notthis", "orthis"]), null);
+        });
+        t.test("should respond with the correct value given a variable argument list of keys with one matching", function() {
+          assert.strictEqual(provider.any("notthis", "orthis", "key"), 'getThisValue');
+        });
+        t.test("should respond with null given no arguments", function() {
+          assert.strictEqual(provider.any(), null);
+        });
+      })
+      t.describe("with a callback", function() {
+        t.test("should respond with the correct value given an array of keys with one matching", function(done) {
+          provider.any(["notthis", "orthis", "key"], (err, value) => {
+            assert.strictEqual(value, 'getThisValue');
+            done();
+          });
+        });
+        t.test("should respond with an undefined value given an array of keys with no match", function(done) {
+          provider.any(["notthis", "orthis"], (err, value) => {
+            assert.strictEqual(value, undefined)
+            done();
+          });
+        });
+        t.test("should respond with the correct value given a variable argument list of keys with one matching", function(done) {
+          provider.any("notthis", "orthis", "key", (err, value) => {
+            assert.strictEqual(value, 'getThisValue');
+            done();
+          });
+        });
+
+        t.test("should respond with an undefined value given no keys", function(done) {
+          provider.any((err, value) => {
+            assert.strictEqual(value, undefined)
+            done();
+          });
+        });
+      })
+    })
+  })
+});