Simplify version guard

- Updated index.js test to run in Node.js and browsers
- Simplified message and clarified case where two of the same versions would conflict

index.js

@@ -1,20 +1,18 @@
+'use strict';
+
 var bitcore = module.exports;
 
 // module information
 bitcore.version = 'v' + require('./package.json').version;
-
-if (global._bitcore !== undefined) {
-  var versions = bitcore.version + ' and ' + global._bitcore;
-  var message = 'More than one instance of bitcore found with different versions: ' + versions;
-  if (typeof window === 'undefined') {
-    message += '. Make sure there are no version conflicts between package.json files of your ' +
-      'dependencies. This could also happen when a package depends on a git repository.';
-  } else {
-    message += '. Make sure any scripts included don\'t contain their own bitcore bundle.';
+bitcore.versionGuard = function(version) {
+  if (version !== undefined) {
+    var message = 'More than one instance of bitcore found with versions: ' + bitcore.version +
+      ' and ' + version + '. Please make sure to require bitcore and check that submodules do' +
+      ' not also include their own bitcore dependency.';
+    throw new Error(message);
   }
-
-  throw new Error(message);
-}
+};
+bitcore.versionGuard(global._bitcore);
 global._bitcore = bitcore.version;
 
 // crypto

test/index.js

@@ -1,39 +1,16 @@
 'use strict';
 
-var expect = require('chai').expect;
+var should = require('chai').should();
 var bitcore = require('../');
 
-// current tests works only in node.js
-var bdescribe = typeof window === 'undefined' ? describe : xdescribe
-bdescribe('index.js', function() {
-  var bitcoreModulePath;
-  var bitcoreModule;
-
-  before(function() {
-    bitcoreModulePath = require.resolve('../');
-    bitcoreModule = require.cache[bitcoreModulePath];
-    delete require.cache[bitcoreModulePath];
-  });
-
-  after(function() {
-    require.cache[bitcoreModulePath] = bitcoreModule;
-  });
-
-  function importBitcore() {
-    require('../');
-  }
-
+describe('#versionGuard', function() {
   it('global._bitcore should be defined', function() {
-    expect(global._bitcore).to.equal(bitcore.version);
-  });
-
-  it('throw error on importing other bitcore module', function() {
-    expect(importBitcore).to.throw(Error);
+    should.equal(global._bitcore, bitcore.version);
   });
 
-  it('throw error on importing with defined window', function () {
-    global.window = 'window hack';
-    expect(importBitcore).to.throw(Error);
-    delete global.window;
+  it('throw an error if version is already defined', function() {
+    (function() {
+      bitcore.versionGuard('version');
+    }).should.throw('More than one instance of bitcore');
   });
 });