Allow to set config location

Author: Andrey Kuzmin

index.js

@@ -110,11 +110,24 @@ function withConfigLoader(cb) {
       })
     } else {
       var postcssLoadConfig = require('postcss-load-config')
+      var contextOptions = plugins || {}
       return cb(function(file) {
-        return postcssLoadConfig({
-          file: file
-        , options: plugins
-        })
+        var configPath
+        if (contextOptions.config) {
+          if (path.isAbsolute(contextOptions.config)) {
+            configPath = contextOptions.config
+          } else {
+            configPath = path.join(file.base, contextOptions.config)
+          }
+        } else {
+          configPath = file.dirname
+        }
+        return postcssLoadConfig(
+          { file: file
+          , options: contextOptions
+          },
+          configPath
+        )
       })
     }
   }

test.js

@@ -168,8 +168,8 @@ describe('PostCSS Guidelines', function () {
       postcssStub.use(plugins)
       return postcssStub
     }
-  , 'postcss-load-config': function (ctx) {
-      return postcssLoadConfigStub(ctx)
+  , 'postcss-load-config': function (ctx, configPath) {
+      return postcssLoadConfigStub(ctx, configPath)
     }
   , 'vinyl-sourcemaps-apply': function () {
       return {}
@@ -303,6 +303,67 @@ describe('PostCSS Guidelines', function () {
 
   })
 
+  it('should point the config location to file directory', function (cb) {
+    var cssPath = __dirname + '/fixture.css'
+    var stream = postcss()
+    postcssLoadConfigStub.returns(Promise.resolve({ plugins: [] }))
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    }))
+    stream.on('data', function () {
+      assert.deepEqual(postcssLoadConfigStub.getCall(0).args[1], __dirname)
+      cb()
+    })
+    stream.end(new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    }))
+  })
+
+  it('should set the config location from option', function (cb) {
+    var cssPath = __dirname + '/fixture.css'
+    var stream = postcss({ config: '/absolute/path' })
+    postcssLoadConfigStub.returns(Promise.resolve({ plugins: [] }))
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    }))
+    stream.on('data', function () {
+      assert.deepEqual(postcssLoadConfigStub.getCall(0).args[1], '/absolute/path')
+      cb()
+    })
+    stream.end(new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    }))
+  })
+
+  it('should set the config location from option relative to the base dir', function (cb) {
+    var cssPath = __dirname + '/src/fixture.css'
+    var stream = postcss({ config: './relative/path' })
+    postcssLoadConfigStub.returns(Promise.resolve({ plugins: [] }))
+    postcssStub.process.returns(Promise.resolve({
+      css: ''
+    , warnings: function () {
+        return []
+      }
+    }))
+    stream.on('data', function () {
+      assert.deepEqual(postcssLoadConfigStub.getCall(0).args[1], __dirname + '/relative/path')
+      cb()
+    })
+    stream.end(new gutil.File({
+      contents: new Buffer('a {}')
+    , path: cssPath
+    , base: __dirname
+    }))
+  })
+
   it('should not override `from` and `map` if using gulp-sourcemaps', function (cb) {
     var stream = postcss([ doubler ], { from: 'overriden', map: 'overriden' })
     var cssPath = __dirname + '/fixture.css'