diff --git a/.editorconfig b/.editorconfig
index 2f868c7..ec0fd49 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -5,7 +5,7 @@ charset = utf-8
 end_of_line = lf
 insert_final_newline = true
 indent_style = space
-indent_size = 4
+indent_size = 2
 trim_trailing_whitespace = true
 
 # Do not trim in jade files
diff --git a/.eslintrc b/.eslintrc
index c6e7fd9..95a4da2 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -12,5 +12,8 @@
     ],
     "plugins": [
         "@coorpacademy/coorpacademy"
-    ]
-}
\ No newline at end of file
+    ],
+    "rules": {
+      "promise/no-native": 0
+    }
+}
diff --git a/package.json b/package.json
index b903476..055e485 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,7 @@
     "rxjs": "^5.0.0-beta.7"
   },
   "devDependencies": {
-    "@coorpacademy/eslint-plugin-coorpacademy": "^1.2.1",
+    "@coorpacademy/eslint-plugin-coorpacademy": "^2.0.0",
     "ava": "^0.16.0",
     "babel-cli": "^6.18.0",
     "babel-core": "^6.18.2",
@@ -49,6 +49,8 @@
     "coveralls": "^2.11.15",
     "eslint": "^3.10.2",
     "eslint-plugin-ava": "^4.0.0",
+    "eslint-plugin-fp": "^2.2.0",
+    "eslint-plugin-import": "^2.2.0",
     "eslint-plugin-lodash-fp": "^2.1.3",
     "nyc": "^9.0.1"
   },
diff --git a/src/api.js b/src/api.js
index 88439fc..bb3e7fa 100644
--- a/src/api.js
+++ b/src/api.js
@@ -1,4 +1,7 @@
-import path from 'path';
+import {
+    join,
+    relative
+} from 'path';
 import {
   find,
   getOr,
@@ -6,9 +9,9 @@ import {
   startsWith,
   curry
 } from 'lodash/fp';
-import {stringify, parseValue} from './parse';
-import {set$} from './util/etcd';
 import createDebug from 'debug';
+import {set$} from './util/etcd';
+import {stringify, parseValue} from './parse';
 
 const debug = createDebug('squirrel');
 
@@ -30,29 +33,29 @@ const createAPI = (store, client, options = {cwd: '/'}) => {
     return getByRaw(index, key).then(getOr(null, ['value']));
   };
 
+  const _get = curry((_path, node) => {
+    if (!node) return null;
+    if (relative(node.key, _path) === '') return node;
+
+    return _get(_path, find(function(child) {
+      return startsWith(child.key, _path);
+    }, node.nodes));
+  });
+
   const get = path => {
     debug(`get => ${path}`);
     return store('node').then(_get(path));
   };
 
   const set = (_path, value) => {
-    _path = path.join(options.cwd, _path);
-    debug(`set => ${_path}`);
-    return set$(client, _path, stringify(value))
+    const fullPath = join(options.cwd, _path);
+    debug(`set => ${fullPath}`);
+    return set$(client, fullPath, stringify(value))
         .pluck('node', 'value')
         .map(parseValue)
         .toPromise();
   };
 
-  const _get = curry((_path, node) => {
-    if (!node) return null;
-    if (path.relative(node.key, _path) === '') return node;
-
-    return _get(_path, find(function(child) {
-      return startsWith(child.key, _path);
-    }, node.nodes));
-  });
-
   return {
     getBy,
     getByRaw,
diff --git a/src/bin/sync.js b/src/bin/sync.js
index b2e5c0b..c7164c6 100644
--- a/src/bin/sync.js
+++ b/src/bin/sync.js
@@ -2,9 +2,8 @@
 
 import {resolve} from 'path';
 import minimist from 'minimist';
-
-import makeEtcdClient from './etcd';
 import {sync$} from '../util/cli';
+import makeEtcdClient from './etcd';
 
 const argz = minimist(process.argv.slice(2));
 
@@ -13,6 +12,7 @@ const pathETCD = resolve('/', argz._[1]);
 
 const client = makeEtcdClient(argz);
 
-sync$(client, pathFS, pathETCD).toPromise().then(() =>
-  process.stdout.write(`The end.\n`)
+sync$(client, pathFS, pathETCD).toPromise().then( // eslint-disable-line promise/catch-or-return
+  () => process.stdout.write(`The end.\n`),
+  err => process.stderr.write(`${err.stack}\n`)
 );
diff --git a/src/bin/watch.js b/src/bin/watch.js
index 3931010..83b84ec 100644
--- a/src/bin/watch.js
+++ b/src/bin/watch.js
@@ -2,10 +2,9 @@
 
 import {resolve} from 'path';
 import minimist from 'minimist';
-
-import makeEtcdClient from './etcd';
 import createWatcher$ from '../watch';
 import {stringify} from '../parse';
+import makeEtcdClient from './etcd';
 
 const argz = minimist(process.argv.slice(2));
 
diff --git a/src/build-index.js b/src/build-index.js
index 1340e25..4ffbef9 100644
--- a/src/build-index.js
+++ b/src/build-index.js
@@ -1,31 +1,39 @@
 import {
   assign,
+  cond,
+  constant,
   flatMap,
   get,
+  getOr,
   map,
   pipe,
   reduce,
   zipObject
 } from 'lodash/fp';
 import createDebug from 'debug';
-const debug = createDebug('squirrel:indexer');
 
-const updateIndexes = indexes => store => {
-  debug(`Update indexes ${indexes.join(',')}`);
-  return zipObject(indexes, map(function(index) {
-    return buildIndex(index, store);
-  }, indexes));
-};
+const debug = createDebug('squirrel:indexer');
 
 const buildIndex = (index, node) => {
   const value = get(index, node.value);
 
   return pipe(
+    cond([
+        [get('dir'), getOr([], 'nodes')],
+        [constant(true), constant([])]
+    ]),
     flatMap(function(child) {
       return buildIndex(index, child);
     }),
     reduce(assign, value ? zipObject([get(index, node.value)], [node]) : {})
-  )(node.dir && node.nodes || []);
+  )(node);
+};
+
+const updateIndexes = indexes => store => {
+  debug(`Update indexes ${indexes.join(',')}`);
+  return zipObject(indexes, map(function(index) {
+    return buildIndex(index, store);
+  }, indexes));
 };
 
 export default updateIndexes;
diff --git a/src/combine.js b/src/combine.js
index d7cfed7..41cbe6e 100644
--- a/src/combine.js
+++ b/src/combine.js
@@ -1,5 +1,6 @@
-import {set, del} from './patch';
 import createDebug from 'debug';
+import {set, del} from './patch';
+
 const debug = createDebug('squirrel:combine');
 
 const createCombiner$ = event$ => {
diff --git a/src/fallback.js b/src/fallback.js
index c1af9ea..b62e3c8 100644
--- a/src/fallback.js
+++ b/src/fallback.js
@@ -1,8 +1,9 @@
 import {readFile} from 'fs';
 import {isString, identity} from 'lodash/fp';
 import {Observable} from 'rxjs';
-import {parseAction} from './parse';
 import createDebug from 'debug';
+import {parseAction} from './parse';
+
 const debug = createDebug('squirrel:fallback');
 
 const readFile$ = Observable.bindNodeCallback(readFile);
diff --git a/src/fetch.js b/src/fetch.js
index c26a9d9..c90459c 100644
--- a/src/fetch.js
+++ b/src/fetch.js
@@ -1,6 +1,7 @@
 import {Observable} from 'rxjs';
-import {parseAction} from './parse';
 import createDebug from 'debug';
+import {parseAction} from './parse';
+
 const debug = createDebug('squirrel:etcd');
 
 const createFetch$ = (client, cwd) => {
diff --git a/src/index.js b/src/index.js
index bff63e6..269e46e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -6,7 +6,6 @@ import {
 import Etcd from 'node-etcd';
 import {Observable} from 'rxjs';
 import createDebug from 'debug';
-
 import createEtcd$ from './etcd';
 import createFallback$ from './fallback';
 import createCombiner$ from './combine';
@@ -17,9 +16,9 @@ import createIndexBuilder from './build-index';
 
 const debug = createDebug('squirrel');
 
-const createSquirrel = options => {
+const createSquirrel = _options => {
   debug('Init');
-  options = assign({
+  const options = assign({
     hosts: 'http://localhost:2379',
     auth: null,
     ca: null,
@@ -30,7 +29,7 @@ const createSquirrel = options => {
 
     cwd: '/',
     indexes: []
-  }, options);
+  }, _options);
 
   const client = new Etcd(options.hosts, pick(['auth', 'ca', 'key', 'cert'], options));
   const indexBuilder = createIndexBuilder(options.indexes);
diff --git a/src/parse.js b/src/parse.js
index f8e06b1..6bf10ae 100644
--- a/src/parse.js
+++ b/src/parse.js
@@ -26,10 +26,10 @@ export const parseNode = pipe(
 );
 
 export const parseAction = action => {
-  return reduce((action, key) => {
-    if (has(key, action)) {
-      return set(key, parseNode(get(key, action)), action);
+  return reduce((_action, key) => {
+    if (has(key, _action)) {
+      return set(key, parseNode(get(key, _action)), _action);
     }
-    return action;
+    return _action;
   }, action, ['node', 'prevNode']);
 };
diff --git a/src/patch.js b/src/patch.js
index 55409cb..c2e3aad 100644
--- a/src/patch.js
+++ b/src/patch.js
@@ -7,6 +7,7 @@ import {
   startsWith
 } from 'lodash/fp';
 import createDebug from 'debug';
+
 const debug = createDebug('squirrel:patch');
 
 const get = (store, {action, node}) => {
diff --git a/src/resync.js b/src/resync.js
index 598620f..b11f258 100644
--- a/src/resync.js
+++ b/src/resync.js
@@ -1,6 +1,7 @@
 import {Observable} from 'rxjs';
-import createFetcher$ from './fetch';
 import createDebug from 'debug';
+import createFetcher$ from './fetch';
+
 const debug = createDebug('squirrel:etcd');
 
 const createResync$ = (client, cwd, events$) =>
diff --git a/src/save.js b/src/save.js
index a74a288..55b628e 100644
--- a/src/save.js
+++ b/src/save.js
@@ -3,6 +3,7 @@ import {Observable} from 'rxjs';
 import {isString} from 'lodash/fp';
 import createDebug from 'debug';
 import {stringify} from './parse';
+
 const debug = createDebug('squirrel:save');
 
 const writeFile$ = Observable.bindNodeCallback(writeFile);
diff --git a/src/test/api.js b/src/test/api.js
index 8dc24d3..85c7771 100644
--- a/src/test/api.js
+++ b/src/test/api.js
@@ -1,8 +1,8 @@
 import test from 'ava';
 import createEtcdMock from '../util/test/helpers/etcd';
 import {stringify} from '../parse';
-
 import createAPI from '../api';
+
 const node = {
   key: '/',
   dir: true,
@@ -213,9 +213,9 @@ test('should get null if no node matches this path', async t => {
   );
 });
 
-const createAction = (type, node) => ({
+const createAction = (type, _node) => ({
   type,
-  node
+  node: _node
 });
 const createNode = (key, value) => ({
   key,
@@ -233,9 +233,9 @@ test('should set value if value setted', async t => {
       values: [null, createAction('set', createNode('/foo', {foo: 'baz'})), null]
     }]
   });
-  const api = createAPI(getStore, client);
+  const _api = createAPI(getStore, client);
   t.deepEqual(
-    await api.set('/foo', {foo: 'baz'}),
+    await _api.set('/foo', {foo: 'baz'}),
     {foo: 'baz'}
   );
 });
@@ -244,9 +244,9 @@ test('should failed if error occured', async t => {
   const client = createEtcdMock({
     set: [[new Error('boom'), null, null]]
   });
-  const api = createAPI(getStore, client);
+  const _api = createAPI(getStore, client);
   t.throws(
-    api.set('/foo', {foo: 'baz'}),
+    _api.set('/foo', {foo: 'baz'}),
     /boom/
   );
 });
diff --git a/src/test/combine.js b/src/test/combine.js
index a2b7397..d777041 100644
--- a/src/test/combine.js
+++ b/src/test/combine.js
@@ -1,8 +1,6 @@
 import test from 'ava';
 import {Observable} from 'rxjs';
-
 import createCombiner$ from '../combine';
-
 import emptyRoot from './fixtures/empty-root';
 import setEvent from './fixtures/set-event';
 
diff --git a/src/test/etcd.js b/src/test/etcd.js
index a06f656..a6cc712 100644
--- a/src/test/etcd.js
+++ b/src/test/etcd.js
@@ -1,12 +1,10 @@
-import {EventEmitter} from 'events';
+import {EventEmitter} from 'events'; // eslint-disable-line fp/no-events
 import test from 'ava';
-
 import createEtcd$ from '../etcd';
-
+import createEtcdMock from '../util/test/helpers/etcd';
 import setEvent from './fixtures/set-event';
 import deleteEvent from './fixtures/delete-event';
 import resyncEvent from './fixtures/resync-event';
-import createEtcdMock from '../util/test/helpers/etcd';
 
 test('should composite events observable', async t => {
   const getMocks = [[null, {
diff --git a/src/test/fallback.js b/src/test/fallback.js
index 1bd2d2c..7a270f9 100644
--- a/src/test/fallback.js
+++ b/src/test/fallback.js
@@ -1,9 +1,7 @@
-import test from 'ava';
 import {join} from 'path';
+import test from 'ava';
 import {parseNode} from '../parse';
-
 import createFallback$ from '../fallback';
-
 import expected from './fixtures/fallback';
 
 test('should load fallback', async t => {
diff --git a/src/test/fetch.js b/src/test/fetch.js
index 86aebdf..78bba95 100644
--- a/src/test/fetch.js
+++ b/src/test/fetch.js
@@ -1,10 +1,8 @@
 import test from 'ava';
 import {pipe, fill, map, concat} from 'lodash/fp';
-
 import createFetch$ from '../fetch';
-
-import emptyRoot from './fixtures/empty-root';
 import createEtcdMock from '../util/test/helpers/etcd';
+import emptyRoot from './fixtures/empty-root';
 
 test('should fetch nodes', t => {
   const client = createEtcdMock({
diff --git a/src/test/index.js b/src/test/index.js
index 203c1f4..014872f 100644
--- a/src/test/index.js
+++ b/src/test/index.js
@@ -1,5 +1,5 @@
 import test from 'ava';
-import createClient from '../index';
+import createClient from '../index'; // eslint-disable-line import/default
 
 test('should createClient', t => {
   const client = createClient();
diff --git a/src/test/resync.js b/src/test/resync.js
index d43c556..ed1c13b 100644
--- a/src/test/resync.js
+++ b/src/test/resync.js
@@ -1,11 +1,9 @@
 import test from 'ava';
 import {Observable} from 'rxjs';
-
 import createResyncer$ from '../resync';
-
+import createEtcdMock from '../util/test/helpers/etcd';
 import setEvent from './fixtures/set-event';
 import resyncEvent from './fixtures/resync-event';
-import createEtcdMock from '../util/test/helpers/etcd';
 
 test('should transform resync event', async t => {
   const client = createEtcdMock({
diff --git a/src/test/save.js b/src/test/save.js
index 192857b..81b8d88 100644
--- a/src/test/save.js
+++ b/src/test/save.js
@@ -4,7 +4,6 @@ import {readFile} from 'fs';
 import test from 'ava';
 import {Observable} from 'rxjs';
 import createSave from '../save';
-
 import fallback from './fixtures/fallback';
 
 const readFile$ = Observable.bindNodeCallback(readFile);
diff --git a/src/test/store.js b/src/test/store.js
index 57c8f9e..7c2f864 100644
--- a/src/test/store.js
+++ b/src/test/store.js
@@ -1,7 +1,6 @@
 import {Observable, Subject, Subscription} from 'rxjs';
 import test from 'ava';
 import {identity} from 'lodash/fp';
-
 import createStore from '../store';
 
 test('should get node and indexes', t => {
@@ -12,8 +11,8 @@ test('should get node and indexes', t => {
   } = createStore(node$, identity);
 
   const assert = Promise.all([
-    store('node').then(store =>
-      t.deepEqual(store, 'foo')
+    store('node').then(node =>
+      t.deepEqual(node, 'foo')
     ),
     store('indexes').then(indexes =>
       t.deepEqual(indexes, 'foo')
@@ -48,7 +47,7 @@ test('should return subscription', t => {
   t.true(subscription instanceof Subscription);
 });
 
-test('should', t => {
+test('should', async t => {
   const node$ = Observable.of('foo', 'bar');
 
   const {
@@ -56,13 +55,13 @@ test('should', t => {
     subscription
   } = createStore(node$, identity);
 
-  return Promise.all([
-    store('node').then(store =>
-      t.deepEqual(store, 'bar')
-    ),
-    store('indexes').then(indexes =>
-      t.deepEqual(indexes, 'bar')
-    )
-  ]).then(() => subscription.unsubscribe());
+  const [node, indexes] = await Promise.all([
+    store('node'),
+    store('indexes')
+  ]);
+  t.deepEqual(node, 'bar');
+  t.deepEqual(indexes, 'bar');
+
+  subscription.unsubscribe();
 });
 
diff --git a/src/test/watch.js b/src/test/watch.js
index babf44a..ce70958 100644
--- a/src/test/watch.js
+++ b/src/test/watch.js
@@ -1,12 +1,10 @@
-import {EventEmitter} from 'events';
+import {EventEmitter} from 'events'; // eslint-disable-line fp/no-events
 import test from 'ava';
-
 import createWatcher$ from '../watch';
-
+import createEtcdMock from '../util/test/helpers/etcd';
 import setEvent from './fixtures/set-event';
 import deleteEvent from './fixtures/delete-event';
 import resyncEvent from './fixtures/resync-event';
-import createEtcdMock from '../util/test/helpers/etcd';
 
 test('should create watcher observable', t => {
   t.plan(2);
@@ -20,9 +18,9 @@ test('should create watcher observable', t => {
 
   const watcher$ = createWatcher$(client, '/');
 
-  const assertion = watcher$.first().toPromise().then(event => {
+  const assertion = watcher$.first().do(event => {
     t.deepEqual(event, setEvent);
-  });
+  }).toPromise();
 
   watcher.emit(setEvent.action, setEvent);
 
@@ -55,9 +53,9 @@ test('should, emit set/delete/resync events', t => {
 
   const expected = [setEvent, deleteEvent, resyncEvent];
 
-  const assertion = watcher$.take(3).toArray().toPromise().then(events => {
+  const assertion = watcher$.take(3).toArray().do(events => {
     t.deepEqual(events, expected);
-  });
+  }).toPromise();
 
   expected.forEach(event =>
     watcher.emit(event.action, event)
diff --git a/src/util/cli.js b/src/util/cli.js
index 0eb6c8d..0ed8d5b 100644
--- a/src/util/cli.js
+++ b/src/util/cli.js
@@ -1,21 +1,11 @@
 import {join, relative} from 'path';
 import {Observable} from 'rxjs';
 import {includes, get, filter} from 'lodash/fp';
+import makeDebug from 'debug';
 import {isDirectory$, readdir$, readFileUTF8$} from './fs';
 import {get$, set$, delRecursive$, del$, mkdir$, rmdirRecursive$} from './etcd';
-import makeDebug from 'debug';
-const debug = makeDebug('squirrel:util:cli');
 
-export const sync$ = (client, pathFS, pathETCD) => {
-  debug('sync', pathFS, pathETCD);
-  return isDirectory$(pathFS).flatMap(isDirectory => {
-    if (isDirectory)
-      return syncDirectory$(client, pathFS, pathETCD);
-    return syncFile$(client, pathFS, pathETCD);
-  }).flatMap(entry =>
-    sync$(client, join(pathFS, entry), join(pathETCD, entry))
-  );
-};
+const debug = makeDebug('squirrel:util:cli');
 
 export const syncDirectory$ = (client, pathFS, pathETCD) => {
   debug('syncDirectory', pathFS, pathETCD);
@@ -33,12 +23,12 @@ export const syncDirectory$ = (client, pathFS, pathETCD) => {
 
     const entries = readdir$(pathFS);
 
-    return entries.toArray().flatMap(entries => {
-      const nodeToDelete = filter(node => {
-        return !includes(join(pathFS, relative(pathETCD, node.key)), entries);
+    return entries.toArray().flatMap(_entries => {
+      const nodeToDelete = filter(_node => {
+        return !includes(join(pathFS, relative(pathETCD, _node.key)), _entries);
       }, nodes);
-      const nodeToDelete$ = Observable.from(nodeToDelete).flatMap(node =>
-        delRecursive$(client, node.key)
+      const nodeToDelete$ = Observable.from(nodeToDelete).flatMap(_node =>
+        delRecursive$(client, _node.key)
       );
       return nodeToDelete$;
     }).toArray().flatMap(() => entries);
@@ -61,3 +51,14 @@ export const syncFile$ = (client, pathFS, pathETCD) => {
     return set$(client, pathETCD, file);
   }).combineAll().ignoreElements();
 };
+
+export const sync$ = (client, pathFS, pathETCD) => {
+  debug('sync', pathFS, pathETCD);
+  return isDirectory$(pathFS).flatMap(isDirectory => {
+    if (isDirectory)
+      return syncDirectory$(client, pathFS, pathETCD);
+    return syncFile$(client, pathFS, pathETCD);
+  }).flatMap(entry =>
+    sync$(client, join(pathFS, entry), join(pathETCD, entry))
+  );
+};
diff --git a/src/util/etcd.js b/src/util/etcd.js
index aef5076..ce1cfeb 100644
--- a/src/util/etcd.js
+++ b/src/util/etcd.js
@@ -1,6 +1,7 @@
 import {Observable} from 'rxjs';
 import {invokeArgs} from 'lodash/fp';
 import makeDebug from 'debug';
+
 const debug = makeDebug('squirrel:util:etcd');
 
 const wrap = fnName => (client, ...argz) =>
diff --git a/src/util/fs.js b/src/util/fs.js
index 06f0b82..20e0920 100644
--- a/src/util/fs.js
+++ b/src/util/fs.js
@@ -1,7 +1,7 @@
-import {curry} from 'lodash/fp';
-import {Observable} from 'rxjs';
 import {stat, readdir, readFile} from 'fs';
 import {join} from 'path';
+import {curry} from 'lodash/fp';
+import {Observable} from 'rxjs';
 
 export const stat$ =
   Observable.bindNodeCallback(stat);
@@ -13,10 +13,10 @@ export const readFile$ = Observable.bindNodeCallback(readFile);
 export const readFileUTF8$ = file => readFile$(file, {encoding: 'UTF8'});
 
 export const isFile$ = pathFS =>
-  stat$(pathFS).map(stat => stat.isFile());
+  stat$(pathFS).map(_stat => _stat.isFile());
 
 export const isDirectory$ = pathFS =>
-  stat$(pathFS).map(stat => stat.isDirectory());
+  stat$(pathFS).map(_stat => _stat.isDirectory());
 
 export const filter$ = curry((predicate, value) =>
   predicate(value)
diff --git a/src/util/test/cli.js b/src/util/test/cli.js
index 336a0fe..0ff98a8 100644
--- a/src/util/test/cli.js
+++ b/src/util/test/cli.js
@@ -34,13 +34,14 @@ test('should create etcd directory if not exists', t => {
     }]
   });
 
-  return syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().toPromise().then(events => {
+  return syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().do(events => {
     t.deepEqual(xor(events, ['foo', 'bar']), []);
     t.plan(3);
-  });
+  }).toPromise();
 });
 
-test('should throw error on directory sync if etcd throw unknown error', t => {
+test('should throw error on directory sync if etcd throw unknown error', async t => {
+  t.plan(2);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -54,14 +55,17 @@ test('should throw error on directory sync if etcd throw unknown error', t => {
     }]
   });
 
-  return syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().toPromise().then(() =>
-    t.fail()
-  , () =>
-    Promise.resolve()
-  );
+  try {
+    await syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().toPromise();
+    t.fail();
+  }
+  catch (err) {
+    t.pass();
+  }
 });
 
 test('should remove extra entry of directory', t => {
+  t.plan(3);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -85,13 +89,13 @@ test('should remove extra entry of directory', t => {
     }]
   });
 
-  syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().toPromise().then(events => {
+  return syncDirectory$(client, join(__dirname, 'fixtures/fs'), '/test').toArray().do(events => {
     t.deepEqual(xor(events, ['bar', 'foo']), []);
-    t.plan(3);
-  });
+  }).toPromise();
 });
 
-test('should create file if doesn\t exists', t => {
+test('should create file if doesn\t exists', async t => {
+  t.plan(4);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -113,13 +117,12 @@ test('should create file if doesn\t exists', t => {
     }]
   });
 
-  return syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise().then(events => {
-    t.deepEqual(events, []);
-    t.plan(4);
-  });
+  const events = await syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise();
+  t.deepEqual(events, []);
 });
 
-test('should throw error on file sync if etcd throw unknown error', t => {
+test('should throw error on file sync if etcd throw unknown error', async t => {
+  t.plan(2);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -132,14 +135,17 @@ test('should throw error on file sync if etcd throw unknown error', t => {
     }]
   });
 
-  return syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise().then(() =>
-    t.fail()
-  , () =>
-    Promise.resolve()
-  );
+  try {
+    await syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise();
+    t.fail();
+  }
+  catch (err) {
+    t.pass();
+  }
 });
 
-test('should remove directory if it should be a file', t => {
+test('should remove directory if it should be a file', async t => {
+  t.plan(6);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -185,13 +191,12 @@ test('should remove directory if it should be a file', t => {
     }]
   });
 
-  return syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise().then(events => {
-    t.deepEqual(events, []);
-    t.plan(6);
-  });
+  const events = await syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise();
+  t.deepEqual(events, []);
 });
 
-test('should remove file if it should be a directory', t => {
+test('should remove file if it should be a directory', async t => {
+  t.plan(4);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -232,13 +237,12 @@ test('should remove file if it should be a directory', t => {
     }]
   });
 
-  return syncDirectory$(client, join(__dirname, 'fixtures/fs/bar'), '/test/bar').toArray().toPromise().then(events => {
-    t.deepEqual(events, ['baz']);
-    t.plan(4);
-  });
+  const events = await syncDirectory$(client, join(__dirname, 'fixtures/fs/bar'), '/test/bar').toArray().toPromise();
+  t.deepEqual(events, ['baz']);
 });
 
-test('should update file if it\'s outdated', t => {
+test('should update file if it\'s outdated', async t => {
+  t.plan(4);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -270,13 +274,12 @@ test('should update file if it\'s outdated', t => {
     }]
   });
 
-  return syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise().then(events => {
-    t.deepEqual(events, []);
-    t.plan(4);
-  });
+  const events = await syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise();
+  t.deepEqual(events, []);
 });
 
-test('shouldn\'t update file if it\'s updated', t => {
+test('shouldn\'t update file if it\'s updated', async t => {
+  t.plan(2);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -295,13 +298,12 @@ test('shouldn\'t update file if it\'s updated', t => {
     }]
   });
 
-  return syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise().then(events => {
-    t.deepEqual(events, []);
-    t.plan(2);
-  });
+  const events = await syncFile$(client, join(__dirname, 'fixtures/fs/foo'), '/test/foo').toArray().toPromise();
+  t.deepEqual(events, []);
 });
 
-test('should loop on sync', t => {
+test('should loop on sync', async t => {
+  t.plan(7);
   const client = createEtcdMock({
     get: [{
       assert: key =>
@@ -361,7 +363,5 @@ test('should loop on sync', t => {
     }]
   });
 
-  return sync$(client, join(__dirname, 'fixtures/fs'), '/test').toPromise().then(() => {
-    t.plan(7);
-  });
+  await sync$(client, join(__dirname, 'fixtures/fs'), '/test').toPromise();
 });
diff --git a/src/util/test/etcd.js b/src/util/test/etcd.js
index 017b093..27e2fe9 100644
--- a/src/util/test/etcd.js
+++ b/src/util/test/etcd.js
@@ -14,7 +14,7 @@ import {
   isFile
 } from '../etcd';
 
-const action = (action, node, prevNode) => ({action, node, prevNode});
+const action = (_action, _node, _prevNode) => ({action: _action, node: _node, prevNode: _prevNode});
 const node = (key, value, dir) => ({key, value, dir});
 const headers = () => ({'content-type': 'application/json'});
 
@@ -75,9 +75,9 @@ const headers = () => ({'content-type': 'application/json'});
   argz: ['foo', 'foo'],
   results: [action('set', node('/foo', 'foo'), node('/foo', 'bar')), headers]
 }].forEach(({title, fn$, fn, argz, expected, results}) => {
-  test(title, t => {
+  test(title, async t => {
     t.plan(3);
-    return fn$({
+    const events = await fn$({
       [fn]: (..._argz) => {
         const cb = _argz.pop();
         t.deepEqual(expected || argz, _argz);
@@ -88,9 +88,8 @@ const headers = () => ({'content-type': 'application/json'});
           }
         };
       }
-    }, ...argz).toArray().toPromise().then(events =>
-      t.deepEqual(events, slice(0, results.length - 1, results))
-    );
+    }, ...argz).toArray().toPromise();
+    t.deepEqual(events, slice(0, results.length - 1, results));
   });
 
   test(`${title} be cancellable`, t => {
@@ -106,22 +105,25 @@ const headers = () => ({'content-type': 'application/json'});
     }, ...argz).subscribe().unsubscribe();
   });
 
-  test(`${title} raise error`, t => {
-    return fn$({
-      [fn]: (..._argz) => {
-        const cb = _argz.pop();
-        cb(new Error('za'));
-        return {
-          abort: () => {
-            t.pass();
-          }
-        };
-      }
-    }, ...argz).toPromise().then(() => {
-      throw new Error();
-    }, () => {
-      return Promise.resolve();
-    });
+  test(`${title} raise error`, async t => {
+    t.plan(2);
+    try {
+      await fn$({
+        [fn]: (..._argz) => {
+          const cb = _argz.pop();
+          cb(new Error('za'));
+          return {
+            abort: () => {
+              t.pass();
+            }
+          };
+        }
+      }, ...argz).toPromise();
+      t.fail();
+    }
+    catch (err) {
+      t.pass();
+    }
   });
 });
 
diff --git a/src/util/test/fs.js b/src/util/test/fs.js
index d9f5973..fbab9fb 100644
--- a/src/util/test/fs.js
+++ b/src/util/test/fs.js
@@ -1,7 +1,6 @@
 import {join} from 'path';
 import {xor, map, isBuffer} from 'lodash/fp';
 import test from 'ava';
-
 import {isFile$, readdir$, isDirectory$, filter$, readFile$, readFileUTF8$} from '../fs';
 
 const joinTestFolder = (...argz) => join(__dirname, 'fixtures/fs', ...argz);
@@ -61,16 +60,14 @@ test('should filterDirectory directory content', t =>
   )
 );
 
-test('should read file', t =>
-  readFile$(joinTestFolder('foo')).toPromise().then(data => {
-    t.true(isBuffer(data));
-    t.deepEqual(data.toString(), 'foo');
-  })
-);
+test('should read file', async t => {
+  const data = await readFile$(joinTestFolder('foo')).toPromise();
+  t.true(isBuffer(data));
+  t.deepEqual(data.toString(), 'foo');
+});
 
-test('should read UTF8 file', t =>
-  readFileUTF8$(joinTestFolder('foo')).toPromise().then(data => {
-    t.falsy(isBuffer(data));
-    t.deepEqual(data, 'foo');
-  })
-);
+test('should read UTF8 file', async t => {
+  const data = await readFileUTF8$(joinTestFolder('foo')).toPromise();
+  t.falsy(isBuffer(data));
+  t.deepEqual(data, 'foo');
+});
diff --git a/src/util/test/helpers/etcd.js b/src/util/test/helpers/etcd.js
index b9d6c7c..e62e617 100644
--- a/src/util/test/helpers/etcd.js
+++ b/src/util/test/helpers/etcd.js
@@ -1,4 +1,4 @@
-import EventEmitter from 'events';
+import EventEmitter from 'events'; // eslint-disable-line fp/no-events
 import {assign, mapValues, noop, pipe} from 'lodash/fp';
 
 const createWatcher = () => () => {