[core/output] Move widget/module handling inside output

The core.output module now manages the list of modules and retrieves the
widgets inside draw() itself. That way, details of drawing/updating
widgets are not visible from the outside anymore.

tests/core/test_output.py

@@ -1,11 +1,18 @@
-import unittest
 import json
+import unittest
 
 import core.output
+import core.module
+
+class TestModule(core.module.Module):
+    pass
 
 class i3(unittest.TestCase):
     def setUp(self):
         self.i3 = core.output.i3()
+        widget = unittest.mock.MagicMock()
+        widget.full_text.return_value = "test"
+        self.someModule = TestModule([widget, widget, widget])
 
     def tearDown(self):
         pass
@@ -18,8 +25,34 @@ class i3(unittest.TestCase):
         self.assertEqual('\n[', all_data['suffix'])
 
     def test_stop(self):
-        self.assertEqual('\n]', self.i3.stop()['suffix'])
+        self.assertEqual('\n]', self.i3.stop()['suffix'], 'wrong i3bar protocol during stop')
 
-    # TODO: mock a "draw" call
+    def test_no_modules_by_default(self):
+        self.assertEqual(0, len(self.i3.modules()), 'module list should be empty by default')
+
+    def test_register_single_module(self):
+        self.i3.modules(self.someModule)
+        self.assertEqual(1, len(self.i3.modules()), 'setting single module does not work')
+
+    def test_register_multiple_modules(self):
+        self.i3.modules([ self.someModule, self.someModule, self.someModule ])
+        self.assertEqual(3, len(self.i3.modules()), 'setting module list does not work')
+
+    def test_draw_existing_module(self):
+        self.i3.test_draw = unittest.mock.MagicMock(return_value={
+            'data': { 'test': True }, 'suffix': 'end'
+        })
+        self.i3.draw('test_draw')
+        self.i3.test_draw.assert_called_once_with()
+
+    def test_empty_status_line(self):
+        data = self.i3.statusline()
+        self.assertEqual([], data['data'], 'expected empty list of status line entries')
+        self.assertEqual(',', data['suffix'], 'expected "," as suffix')
+
+    def test_statusline(self):
+        self.i3.modules([ self.someModule, self.someModule, self.someModule ])
+        data = self.i3.statusline()
+        self.assertEqual(len(self.someModule.widgets())*3, len(data['data']), 'wrong number of widgets')
 
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