Ensure that the cache default functions gets correctly executed (#150)

src/options/WebpackOptionHelper.js

@@ -25,6 +25,12 @@ class WebpackOptionHelper extends OptionHelper {
       options.cache = false;
     }
 
+    // ensure that when we send the cache option to webpack in watch mode it is not the function
+    // TODO: this is workaround and should be handled in a more generic way
+    if (typeof options.cache === 'function') {
+      options.cache = options.cache(options);
+    }
+
     return this.filterGruntOptions(options);
   }
 }

tests/src/options/WebpackOptionHelper.js

@@ -1,7 +1,7 @@
 import test from 'ava';
 import WebpackOptionHelper from '../../../src/options/WebpackOptionHelper';
 
-test('cache is enabled in watch mode', (t) => {
+test('cache stays enabled in watch mode', (t) => {
   const options = { watch: true, cache: true };
   const helper = new WebpackOptionHelper();
 
@@ -10,6 +10,24 @@ test('cache is enabled in watch mode', (t) => {
   t.true(result.cache);
 });
 
+test('cache is enabled in watch mode by default', (t) => {
+  const options = { watch: true, cache: () => true };
+  const helper = new WebpackOptionHelper();
+
+  const result = helper.filterOptions(options);
+
+  t.true(result.cache);
+});
+
+test('cache is disabled in normal mode by default', (t) => {
+  const options = { watch: false, cache: () => true };
+  const helper = new WebpackOptionHelper();
+
+  const result = helper.filterOptions(options);
+
+  t.false(result.cache);
+});
+
 test('cache is disabled in normal mode', (t) => {
   const options = { watch: false, cache: true };
   const helper = new WebpackOptionHelper();