Allow excluding spec files and helper files

Paths in spec_files and helpers starting with ! will be excluded
from respectively spec files and helper files.

#128

Author: liuxh0

lib/jasmine.js

@@ -155,11 +155,26 @@ function addFiles(kind) {
     var jasmineRunner = this;
     var fileArr = this[kind];
 
+    var includeFiles = [];
+    var excludeFiles = [];
     files.forEach(function(file) {
+      if (file.startsWith('!')) {
+        var excludeFile = file.substring(1);
+        if(!(path.isAbsolute && path.isAbsolute(excludeFile))) {
+          excludeFile = path.join(jasmineRunner.projectBaseDir, jasmineRunner.specDir, excludeFile);
+        }
+
+        excludeFiles.push(excludeFile);
+      } else {
+        includeFiles.push(file);
+      }
+    });
+
+    includeFiles.forEach(function(file) {
       if(!(path.isAbsolute && path.isAbsolute(file))) {
         file = path.join(jasmineRunner.projectBaseDir, jasmineRunner.specDir, file);
       }
-      var filePaths = glob.sync(file);
+      var filePaths = glob.sync(file, { ignore: excludeFiles });
       filePaths.forEach(function(filePath) {
         if(fileArr.indexOf(filePath) === -1) {
           fileArr.push(filePath);

spec/jasmine_spec.js

@@ -63,6 +63,12 @@ describe('Jasmine', function() {
       expect(this.testJasmine.specFiles.map(basename)).toEqual(['command_spec.js', 'jasmine_spec.js']);
     });
 
+    it('add spec files with excluded files', function() {
+      expect(this.testJasmine.specFiles).toEqual([]);
+      this.testJasmine.addSpecFiles(['spec/*.js', '!spec/command*']);
+      expect(this.testJasmine.specFiles.map(basename)).toEqual(['jasmine_spec.js']);
+    });
+
     it('add spec files with glob pattern to existings files', function() {
       var aFile = path.join(this.testJasmine.projectBaseDir, this.testJasmine.specDir, 'spec/command_spec.js');
       this.testJasmine.specFiles = [aFile, 'b'];