move getFlowFromConfig into flow for testability

Also add tests

Author: stephanebachelier

lib/flow.js

@@ -62,3 +62,27 @@ Flow.prototype.setPost = function (post) {
 Flow.prototype.blockTypes = function () {
   return _.union(_.keys(this._steps), _.keys(this._post));
 };
+
+// Default flow configuration for a target
+Flow.defaultConfig = {
+  steps: {
+    js: ['concat', 'uglify'],
+    css: ['concat', 'cssmin']
+  },
+  post: {}
+}
+
+// Retrieve the flow config from the furnished configuration. It can be:
+//  - a dedicated one for the furnished target
+//  - a general one
+//  - the default one
+Flow.getFlowFromConfig = function (config, target) {
+  var flow = new Flow(Flow.defaultConfig);
+
+  if (config.options && config.options.flow) {
+    var flowConfig = config.options.flow[target] ? config.options.flow[target] : config.options.flow;
+    flow.mergeSteps(flowConfig.steps);
+    flow.setPost(flowConfig.post);
+  }
+  return flow;
+};

tasks/usemin.js

@@ -2,27 +2,7 @@
 var util = require('util');
 var chalk = require('chalk');
 
-// Retrieve the flow config from the furnished configuration. It can be:
-//  - a dedicated one for the furnished target
-//  - a general one
-//  - the default one
-var getFlowFromConfig = function (config, target) {
-  var Flow = require('../lib/flow');
-  var flow = new Flow({
-    steps: {
-      js: ['concat', 'uglify'],
-      css: ['concat', 'cssmin']
-    },
-    post: {}
-  });
-
-  if (config.options && config.options.flow) {
-    var flowConfig = config.options.flow[target] ? config.options.flow[target] : config.options.flow;
-    flow.mergeSteps(flowConfig.steps);
-    flow.setPost(flowConfig.post);
-  }
-  return flow;
-};
+var Flow = require('../lib/flow');
 
 //
 // Return which locator to use to get the revisioned version (revved) of the files, with, by order of
@@ -169,7 +149,7 @@ module.exports = function (grunt) {
       .writeln('Going through ' + grunt.log.wordlist(this.filesSrc) + ' to update the config')
       .writeln('Looking for build script HTML comment blocks');
 
-    var flow = getFlowFromConfig(grunt.config('useminPrepare'), this.target);
+    var flow = Flow.getFlowFromConfig(grunt.config('useminPrepare'), this.target);
 
     var c = new ConfigWriter(flow, {
       root: root,

test/test-flow.js

@@ -134,3 +134,78 @@ describe('ConfigWriter', function () {
   });
 
 });
+
+describe('Flow builder from configuration', function () {
+  describe('global flow', function () {
+    it('should enable removing a step for a type', function () {
+      var flow = Flow.getFlowFromConfig({
+        html: 'index.html',
+        options: {
+          flow: {
+            steps: {
+              js: ['uglify']
+            }
+          }
+        }
+      });
+
+      assert.deepEqual(flow.steps('js'), ['uglify']);
+      assert.deepEqual(flow.steps('css'), Flow.defaultConfig.steps.css);
+    });
+
+    it('should enable clearing all steps for a type', function () {
+      var flow = Flow.getFlowFromConfig({
+        html: 'index.html',
+        options: {
+          flow: {
+            steps: {
+              css: []
+            }
+          }
+        }
+      });
+
+      assert.deepEqual(flow.steps('js'), Flow.defaultConfig.steps.js);
+      assert.deepEqual(flow.steps('css'), []);
+    });
+  });
+
+  describe('flow per target', function () {
+    it('should enable removing a step for a type', function () {
+      var flow = Flow.getFlowFromConfig({
+        html: 'index.html',
+        options: {
+          flow: {
+            html: {
+              steps: {
+                js: ['uglify']
+              }
+            }
+          }
+        }
+      }, 'html');
+
+      assert.deepEqual(flow.steps('js'), ['uglify']);
+      assert.deepEqual(flow.steps('css'), Flow.defaultConfig.steps.css);
+    });
+
+    it('should enable clearing all steps for a type', function () {
+      var flow = Flow.getFlowFromConfig({
+        html: 'index.html',
+        options: {
+          flow: {
+            html: {
+              steps: {
+                js: ['uglify'],
+                css: []
+              }
+            }
+          }
+        }
+      }, 'html');
+
+      assert.deepEqual(flow.steps('js'), ['uglify']);
+      assert.deepEqual(flow.steps('css'), []);
+    });
+  });
+});