diff --git a/.gitignore b/.gitignore
index 1296338..e2a293b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,7 @@ lib-cov
 
 # Coverage directory used by tools like istanbul
 coverage
+.nyc_output
 
 # Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
 .grunt
diff --git a/karma.conf.js b/karma.conf.js
index cf70b03..1ffca9b 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -19,6 +19,7 @@ module.exports = function(config) {
       'node_modules/chai/chai.js',
       'dist/regenerator.min.js',
       'dist/nodent.min.js',
+      'node_modules/bluebird/js/browser/bluebird.core.min.js',
       '.browser/*.spec.js'
     ],
 
diff --git a/karma.sauce.js b/karma.sauce.js
index e787518..1316ab0 100644
--- a/karma.sauce.js
+++ b/karma.sauce.js
@@ -113,6 +113,7 @@ module.exports = function(config) {
       'dist/ajv.min.js',
       'node_modules/chai/chai.js',
       'dist/nodent.min.js',
+      'node_modules/bluebird/js/browser/bluebird.core.min.js',
       '.browser/*.spec.js'
     ],
 
diff --git a/package.json b/package.json
index 4f2b32f..89eaecc 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "test-spec": "mocha spec/*.spec.js -R spec",
     "test-fast": "AJV_FAST_TEST=true npm run test-spec",
     "test-debug": "mocha spec/*.spec.js --debug-brk -R spec",
-    "test-cov": "istanbul cover -x '**/spec/**' node_modules/mocha/bin/_mocha -- spec/*.spec.js -R spec",
+    "test-cov": "nyc npm run test-spec",
     "test-ts": "tsc --target ES5 --noImplicitAny lib/ajv.d.ts",
     "bundle": "./scripts/bundle . Ajv pure_getters",
     "bundle-regenerator": "./scripts/bundle regenerator",
@@ -30,6 +30,16 @@
     "prepublish": "npm run build && npm run bundle-all",
     "watch": "watch 'npm run build' ./lib/dot"
   },
+  "nyc": {
+    "exclude": [
+      "**/spec/**",
+      "node_modules"
+    ],
+    "reporter": [
+      "lcov",
+      "text-summary"
+    ]
+  },
   "repository": {
     "type": "git",
     "url": "https://github.com/epoberezkin/ajv.git"
@@ -66,7 +76,6 @@
     "gh-pages-generator": "^0.2.0",
     "glob": "^7.0.0",
     "if-node-version": "^1.0.0",
-    "istanbul": "^0.4.2",
     "js-beautify": "^1.5.6",
     "jshint": "^2.8.0",
     "json-schema-test": "^1.1.1",
@@ -77,6 +86,7 @@
     "karma-sauce-launcher": "^0.3.0",
     "mocha": "^3.0.0",
     "nodent": "^2.5.3",
+    "nyc": "^8.3.0",
     "phantomjs-prebuilt": "^2.1.4",
     "pre-commit": "^1.1.1",
     "regenerator": "0.8.42",
diff --git a/spec/after_test.js b/spec/after_test.js
new file mode 100644
index 0000000..17c0167
--- /dev/null
+++ b/spec/after_test.js
@@ -0,0 +1,19 @@
+'use strict';
+
+var should = require('./chai').should();
+
+exports.error = function (res) {
+  console.log('ajv options:', res.validator._opts);
+};
+
+exports.each = function (res) {
+  // console.log(res.errors);
+  res.valid .should.be.a('boolean');
+  if (res.valid === true ) {
+    should.equal(res.errors, null);
+  } else {
+    res.errors .should.be.an('array');
+    for (var i=0; i<res.errors.length; i++)
+      res.errors[i] .should.be.an('object');
+  }
+};
diff --git a/spec/async_schemas.spec.js b/spec/async_schemas.spec.js
index 29380a6..25551fa 100644
--- a/spec/async_schemas.spec.js
+++ b/spec/async_schemas.spec.js
@@ -3,7 +3,9 @@
 var jsonSchemaTest = require('json-schema-test')
   , Promise = require('./promise')
   , getAjvInstances = require('./ajv_async_instances')
-  , Ajv = require('./ajv');
+  , Ajv = require('./ajv')
+  , suite = require('./brower_test_suite')
+  , after = require('./after_test');
 
 
 var instances = getAjvInstances({ v5: true });
@@ -14,42 +16,23 @@ instances.forEach(addAsyncFormatsAndKeywords);
 
 jsonSchemaTest(instances, {
   description: 'asynchronous schemas tests of ' + instances.length + ' ajv instances with different options',
-  suites: testSuites(),
+  suites: {
+    'async schemas':
+      typeof window == 'object'
+      ? suite(require('./async/{**/,}*.json', {mode: 'list'}))
+      : './async/{**/,}*.json'
+  },
   async: true,
   assert: require('./chai').assert,
   Promise: Promise,
-  afterError: function (res) {
-    console.log('ajv options:', res.validator._opts);
-  },
-  // afterEach: function (res) {
-  //   console.log(res.errors);
-  // },
+  afterError: after.error,
+  // afterEach: after.each,
   cwd: __dirname,
   hideFolder: 'async/',
   timeout: 90000
 });
 
 
-function testSuites() {
-  var suites;
-  if (typeof window == 'object') {
-    suites = {
-      'async schemas': require('./async/{**/,}*.json', {mode: 'list'})
-    };
-    for (var suiteName in suites) {
-      suites[suiteName].forEach(function (suite) {
-        suite.test = suite.module;
-      });
-    }
-  } else {
-    suites = {
-      'async schemas': './async/{**/,}*.json'
-    };
-  }
-  return suites;
-}
-
-
 function addAsyncFormatsAndKeywords (ajv) {
   ajv.addFormat('english_word', {
     async: true,
diff --git a/spec/async_validate.spec.js b/spec/async_validate.spec.js
index 1541d6f..bf550e1 100644
--- a/spec/async_validate.spec.js
+++ b/spec/async_validate.spec.js
@@ -31,7 +31,7 @@ describe('async schemas, formats and keywords', function() {
         maxLength: 3
       };
 
-      return repeat(function() { return Promise.map(instances, test); });
+      return repeat(function() { return Promise.all(instances.map(test)); });
 
       function test(_ajv) {
         var validate = _ajv.compile(schema);
@@ -211,7 +211,7 @@ describe('async schemas, formats and keywords', function() {
         }
       };
 
-      return repeat(function() { return Promise.map(instances, function (_ajv) {
+      return repeat(function() { return Promise.all(instances.map(function (_ajv) {
         var validate = _ajv.compile(schema);
         var _co = useCo(_ajv);
 
@@ -221,7 +221,7 @@ describe('async schemas, formats and keywords', function() {
           shouldBeInvalid( _co(validate({ word: 1 })) ),
           shouldThrow(     _co(validate({ word: 'today' })), 'unknown word' )
         ]);
-      }); });
+      })); });
     });
 
     it('should validate recursive async schema', function() {
@@ -330,7 +330,7 @@ describe('async schemas, formats and keywords', function() {
     });
 
     function recursiveTest(schema, refSchema) {
-      return repeat(function() { return Promise.map(instances, function (_ajv) {
+      return repeat(function() { return Promise.all(instances.map(function (_ajv) {
         if (refSchema) try { _ajv.addSchema(refSchema); } catch(e) {}
         var validate = _ajv.compile(schema);
         var _co = useCo(_ajv);
@@ -349,7 +349,7 @@ describe('async schemas, formats and keywords', function() {
           shouldBeInvalid( _co(validate({ foo: { foo: { foo: 1 }}})) ),
           shouldThrow(     _co(validate({ foo: { foo: { foo: 'today' }}})), 'unknown word' )
         ]);
-      }); });
+      })); });
     }
   });
 
diff --git a/spec/brower_test_suite.js b/spec/brower_test_suite.js
new file mode 100644
index 0000000..9133433
--- /dev/null
+++ b/spec/brower_test_suite.js
@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function (suite) {
+  suite.forEach(function (file) {
+    file.test = file.module;
+  });
+  return suite;
+};
diff --git a/spec/json-schema.spec.js b/spec/json-schema.spec.js
index d55dcab..10c8028 100644
--- a/spec/json-schema.spec.js
+++ b/spec/json-schema.spec.js
@@ -3,36 +3,28 @@
 var jsonSchemaTest = require('json-schema-test')
   , getAjvInstances = require('./ajv_instances')
   , options = require('./ajv_options')
-  , should = require('./chai').should();
+  , suite = require('./brower_test_suite')
+  , after = require('./after_test');
 
 var instances = getAjvInstances(options);
 
 var remoteRefs = {
-  // for JSON-Schema-Test-Suite
   'http://localhost:1234/integer.json': require('./JSON-Schema-Test-Suite/remotes/integer.json'),
   'http://localhost:1234/subSchemas.json': require('./JSON-Schema-Test-Suite/remotes/subSchemas.json'),
   'http://localhost:1234/folder/folderInteger.json': require('./JSON-Schema-Test-Suite/remotes/folder/folderInteger.json'),
-  // for tests
-  'http://localhost:1234/name.json': require('./remotes/name.json')
 };
 
-var remoteRefsWithIds = [
-  require('./remotes/bar.json'),
-  require('./remotes/foo.json'),
-  require('./remotes/buu.json'),
-  require('./remotes/tree.json'),
-  require('./remotes/node.json'),
-  require('./remotes/second.json'),
-  require('./remotes/first.json'),
-  require('./remotes/scope_change.json'),
-];
-
 instances.forEach(addRemoteRefs);
 
 
 jsonSchemaTest(instances, {
-  description: 'Schema tests of ' + instances.length + ' ajv instances with different options',
-  suites: testSuites(),
+  description: 'JSON-Schema Test Suite: ' + instances.length + ' ajv instances with different options',
+  suites: {
+    'JSON-Schema tests draft4':
+      typeof window == 'object'
+      ? suite(require('./JSON-Schema-Test-Suite/tests/draft4/{**/,}*.json', {mode: 'list'}))
+      : './JSON-Schema-Test-Suite/tests/draft4/{**/,}*.json'
+  },
   only: [
     // 'type', 'not', 'allOf', 'anyOf', 'oneOf', 'enum',
     // 'maximum', 'minimum', 'multipleOf', 'maxLength', 'minLength', 'pattern',
@@ -42,55 +34,17 @@ jsonSchemaTest(instances, {
     // 'items', 'additionalItems', 'uniqueItems',
     // 'optional/format', 'optional/bignum',
     // 'ref', 'refRemote', 'definitions',
-    // 'schemas/complex', 'schemas/basic', 'schemas/advanced',
-  ],
-  skip: [
-    'optional/zeroTerminatedFloats'
   ],
+  skip: [ 'optional/zeroTerminatedFloats' ],
   assert: require('./chai').assert,
-  afterError: function (res) {
-    console.log('ajv options:', res.validator._opts);
-  },
-  afterEach: function (res) {
-    // console.log(res.errors);
-    res.valid .should.be.a('boolean');
-    if (res.valid === true ) {
-      should.equal(res.errors, null);
-    } else {
-      res.errors .should.be.an('array');
-      for (var i=0; i<res.errors.length; i++)
-        res.errors[i] .should.be.an('object');
-    }
-  },
+  afterError: after.error,
+  afterEach: after.each,
   cwd: __dirname,
   hideFolder: 'draft4/',
   timeout: 120000
 });
 
 
-function testSuites() {
-  var suites;
-  if (typeof window == 'object') {
-    suites = {
-      'JSON-Schema tests draft4': require('./JSON-Schema-Test-Suite/tests/draft4/{**/,}*.json', {mode: 'list'}),
-      'Advanced schema tests': require('./tests/{**/,}*.json', {mode: 'list'})
-    };
-    for (var suiteName in suites) {
-      suites[suiteName].forEach(function (suite) {
-        suite.test = suite.module;
-      });
-    }
-  } else {
-    suites = {
-      'JSON-Schema tests draft4': './JSON-Schema-Test-Suite/tests/draft4/{**/,}*.json',
-      'Advanced schema tests': './tests/{**/,}*.json'
-    };
-  }
-  return suites;
-}
-
-
 function addRemoteRefs(ajv) {
   for (var id in remoteRefs) ajv.addSchema(remoteRefs[id], id);
-  ajv.addSchema(remoteRefsWithIds);
 }
diff --git a/spec/promise.js b/spec/promise.js
index 8370eff..8c55c87 100644
--- a/spec/promise.js
+++ b/spec/promise.js
@@ -1,12 +1,11 @@
 'use strict';
 
-var Promise = require('bluebird');
-
-Promise.config({ warnings: false });
-
 var g = typeof global == 'object' ? global :
         typeof window == 'object' ? window : this;
 
-g.Promise = g.Promise || Promise;
+if (!g.Promise) {
+  g.Promise = require('' + 'bluebird');
+  g.Promise.config({ warnings: false });
+}
 
-module.exports = Promise;
+module.exports = g.Promise;
diff --git a/spec/schema-tests.spec.js b/spec/schema-tests.spec.js
new file mode 100644
index 0000000..8a7b17f
--- /dev/null
+++ b/spec/schema-tests.spec.js
@@ -0,0 +1,53 @@
+'use strict';
+
+var jsonSchemaTest = require('json-schema-test')
+  , getAjvInstances = require('./ajv_instances')
+  , options = require('./ajv_options')
+  , suite = require('./brower_test_suite')
+  , after = require('./after_test');
+
+var instances = getAjvInstances(options);
+
+var remoteRefs = {
+  'http://localhost:1234/integer.json': require('./JSON-Schema-Test-Suite/remotes/integer.json'),
+  'http://localhost:1234/folder/folderInteger.json': require('./JSON-Schema-Test-Suite/remotes/folder/folderInteger.json'),
+  'http://localhost:1234/name.json': require('./remotes/name.json')
+};
+
+var remoteRefsWithIds = [
+  require('./remotes/bar.json'),
+  require('./remotes/foo.json'),
+  require('./remotes/buu.json'),
+  require('./remotes/tree.json'),
+  require('./remotes/node.json'),
+  require('./remotes/second.json'),
+  require('./remotes/first.json'),
+  require('./remotes/scope_change.json'),
+];
+
+instances.forEach(addRemoteRefs);
+
+
+jsonSchemaTest(instances, {
+  description: 'Schema tests of ' + instances.length + ' ajv instances with different options',
+  suites: {
+    'Advanced schema tests':
+      typeof window == 'object'
+      ? suite(require('./tests/{**/,}*.json', {mode: 'list'}))
+      : './tests/{**/,}*.json'
+  },
+  only: [
+    // 'schemas/complex', 'schemas/basic', 'schemas/advanced',
+  ],
+  assert: require('./chai').assert,
+  afterError: after.error,
+  afterEach: after.each,
+  cwd: __dirname,
+  timeout: 120000
+});
+
+
+function addRemoteRefs(ajv) {
+  for (var id in remoteRefs) ajv.addSchema(remoteRefs[id], id);
+  ajv.addSchema(remoteRefsWithIds);
+}
diff --git a/spec/v5.spec.js b/spec/v5.spec.js
index c27a2b4..9d21a8e 100644
--- a/spec/v5.spec.js
+++ b/spec/v5.spec.js
@@ -2,42 +2,24 @@
 
 var jsonSchemaTest = require('json-schema-test')
   , getAjvInstances = require('./ajv_instances')
-  , options = require('./ajv_options');
+  , options = require('./ajv_options')
+  , suite = require('./brower_test_suite')
+  , after = require('./after_test');
 
 var instances = getAjvInstances(options, { v5: true });
 
 
 jsonSchemaTest(instances, {
   description: 'v5 schemas tests of ' + instances.length + ' ajv instances with different options',
-  suites: testSuites(),
-  assert: require('./chai').assert,
-  afterError: function (res) {
-    console.log('ajv options:', res.validator._opts);
+  suites: {
+    'v5 proposals': typeof window == 'object'
+                    ? suite(require('./v5/{**/,}*.json', {mode: 'list'}))
+                    : './v5/{**/,}*.json'
   },
-  // afterEach: function (res) {
-  //   console.log(res.errors);
-  // },
+  assert: require('./chai').assert,
+  afterError: after.error,
+  afterEach: after.each,
   cwd: __dirname,
   hideFolder: 'v5/',
   timeout: 90000
 });
-
-
-function testSuites() {
-  var suites;
-  if (typeof window == 'object') {
-    suites = {
-      'v5 proposals': require('./v5/{**/,}*.json', {mode: 'list'})
-    };
-    for (var suiteName in suites) {
-      suites[suiteName].forEach(function (suite) {
-        suite.test = suite.module;
-      });
-    }
-  } else {
-    suites = {
-      'v5 proposals': './v5/{**/,}*.json'
-    };
-  }
-  return suites;
-}