feat(task): let Grunt do the file matching

Use the task's `files` property, but merge with `options.files`,
so we can specify some files that should be available in all test-targets.
Grunt's file objects may be extended with the file options supported
by Karma (included, watched).
Projects that use the undocumented `karma.<target>.files` option should
rename this option and use `karma.<target>.src` instead.

README.md

@@ -65,6 +65,36 @@ karma: {
 To change the `logLevel` in the grunt config file instead of the karma config, use one of the following strings:
 `OFF`, `ERROR`, `WARN`, `INFO`, `DEBUG`
 
+The `files` option can be extended "per-target" in the typical way
+Grunt handles [files][grunt-config-files]:
+
+```js
+karma: {
+  options: {
+    files: ['lib/**/*.js']
+  },
+  unit: {
+    files: [
+      { src: ['test/**/*.js'] }
+    ]
+  }
+}
+```
+
+When using the "Grunt way" of specifying files, you can also extend the
+file objects with the options [supported by karma][karma-config-files]:
+
+```js
+karma: {
+  unit: {
+    files: [
+      { src: ['test/**/*.js'], served: true },
+      { src: ['lib/**/*.js'], served: true, included: false }
+    ]
+  }
+}
+```
+
 ### Config with Grunt Template Strings in `files`
 
 When using template strings in the `files` option, the results will flattened. Therefore, if you include a variable that includes an array, the array will be flattened before being passed to Karma.
@@ -200,7 +230,9 @@ $ grunt karma:dev watch --grep=mypattern
 ## License
 MIT License
 
-[karma-config-file]: http://karma-runner.github.com/0.8/config/configuration-file.html
+[karma-config-file]: http://karma-runner.github.com/0.12/config/configuration-file.html
+[karma-config-files]: http://karma-runner.github.io/0.12/config/files.html
+[grunt-config-files]: http://gruntjs.com/configuring-tasks#files
 [grunt-contrib-watch]: https://github.com/gruntjs/grunt-contrib-watch
 [PhantomJS]: http://phantomjs.org/
 [karma-mocha]: https://github.com/karma-runner/karma-mocha

tasks/grunt-karma.js

@@ -30,12 +30,11 @@ module.exports = function(grunt) {
   grunt.registerMultiTask('karma', 'run karma.', function() {
     var done = this.async();
     var options = this.options({
-      background: false
+      background: false,
+      files: [],
+      client: {}
     });
 
-    if (!options.client) {
-        options.client = {};
-    }
     // Allow for passing cli arguments to `client.args` using  `--grep=x`
     var args = parseArgs(process.argv.slice(2));
     if (_.isArray(options.client.args)) {
@@ -69,9 +68,20 @@ module.exports = function(grunt) {
       data.configFile = path.resolve(data.configFile);
     }
 
-    if (data.files){
-      data.files = _.flatten(data.files);
-    }
+    data.files = [].concat.apply(options.files, this.files.map(function(file) {
+      return file.src.map(function(src) {
+        var obj = {
+          pattern: src
+        };
+
+        ['watched', 'served', 'included'].forEach(function(opt) {
+          if (opt in file) {
+            obj[opt] = file[opt];
+          }
+        });
+        return obj;
+      });
+    }));
 
     // Allow the use of templates in preprocessors
     if (_.isPlainObject(data.preprocessors)) {