YAML: Add package importing feature

```yaml
imports:
  # single task
  - rkd.standardlib.docker.TagImageTask
  # package
  - rkd.standardlib.docker
  ```

.rkd/makefile.py

@@ -1,9 +1,8 @@
 
 from rkd.syntax import TaskAliasDeclaration as Task
 from rkd.standardlib.python import imports as PythonImports
-from rkd.standardlib.docker import imports as DockerImports
 
-IMPORTS = [] + PythonImports() + DockerImports()
+IMPORTS = [] + PythonImports()
 
 TASKS = [
     Task(':release', description='Release RKD to PyPI (snapshot when on master, release on tag)',

.rkd/makefile.yaml

@@ -1,6 +1,7 @@
 version: org.riotkit.rkd/0.3
 imports:
-  - rkd.standardlib.docker.TagImageTask
+  #- rkd.standardlib.docker.TagImageTask  # example of importing single task without dependencies
+  - rkd.standardlib.docker                # example of importing a package with dependencies
 
 tasks:
   :examples:bash-test:

src/rkd/yaml_context.py

@@ -1,8 +1,8 @@
-
 import yaml
 import ast
 import os
 import importlib
+from types import FunctionType
 from argparse import ArgumentParser
 from typing import List, Tuple, Union, Callable
 from traceback import format_exc
@@ -182,7 +182,23 @@ def arguments_callback(parser: ArgumentParser):
 
     @staticmethod
     def parse_imports(classes: List[str]) -> List[TaskDeclaration]:
-        """ Parses imports strings into Python classes """
+        """Parses imports strings into Python classes
+
+        Args:
+            classes: List of classes to import
+
+        Returns:
+            A list of basic task declarations with imported tasks inside
+            [
+                TaskDeclaration(ProtestWorkplaceTask()),
+                TaskDeclaration(StrikeWorkplaceTask()),
+                TaskDeclaration(OccupyWorkplaceTask()),
+                TaskDeclaration(RunProductionByWorkersOnTheirOwnTask())
+            ]
+
+        Raises:
+            YamlParsingException: When a class or module does not exist
+        """
 
         parsed: List[TaskDeclaration] = []
 
@@ -191,6 +207,12 @@ def parse_imports(classes: List[str]) -> List[TaskDeclaration]:
             class_name = parts[-1]
             import_path = '.'.join(parts[:-1])
 
+            # Test if it's not a class name
+            # In this case we treat is as a module and import an importing method imports()
+            if class_name.lower() == class_name:
+                import_path += '.' + class_name
+                class_name = 'imports'
+
             try:
                 module = importlib.import_module(import_path)
             except ImportError as e:
@@ -200,9 +222,12 @@ def parse_imports(classes: List[str]) -> List[TaskDeclaration]:
 
             if class_name not in dir(module):
                 raise YamlParsingException('Import "%s" is invalid. Class "%s" not found in module "%s"' % (
-                    import_str, import_path, class_name
+                    import_str, class_name, import_path
                 ))
 
-            parsed.append(TaskDeclaration(module.__getattribute__(class_name)()))
+            if isinstance(module.__getattribute__(class_name), FunctionType):
+                parsed += module.__getattribute__(class_name)()
+            else:
+                parsed.append(TaskDeclaration(module.__getattribute__(class_name)()))
 
         return parsed

test/test_yaml_context.py

@@ -10,12 +10,24 @@
 
 
 class TestYamlContext(unittest.TestCase):
-    def test_parse_imports_successful_case(self):
+    def test_parse_imports_successful_case_single_task(self):
         factory = YamlParser(NullSystemIO())
         imported = factory.parse_imports(['rkd.standardlib.python.PublishTask'])
 
         self.assertEqual(':py:publish', imported[0].to_full_name())
 
+    def test_parse_imports_successful_case_module(self):
+        factory = YamlParser(NullSystemIO())
+        imported = factory.parse_imports(['rkd.standardlib.python'])
+
+        names_of_imported_tasks = []
+
+        for task in imported:
+            names_of_imported_tasks.append(task.to_full_name())
+
+        self.assertIn(':py:publish', names_of_imported_tasks)
+        self.assertIn(':py:build', names_of_imported_tasks)
+
     def test_parse_imports_wrong_class_type_but_existing(self):
         def test():
             factory = YamlParser(NullSystemIO())
@@ -59,6 +71,7 @@ def test_parse_tasks_successful_case(self):
                          msg='Expected that the task name will be present')
 
         declaration = parsed_tasks[0]
+        declaration.get_task_to_execute()._io = NullSystemIO()
         declaration.get_task_to_execute().execute(ExecutionContext(declaration))
 
         with open('/tmp/.test_parse_tasks', 'r') as test_helper:
@@ -88,6 +101,7 @@ def test_parse_tasks_signals_error_instead_of_throwing_exception(self):
         parsed_tasks = factory.parse_tasks(input_tasks, '')
 
         declaration = parsed_tasks[0]
+        declaration.get_task_to_execute()._io = IO()
         task = declaration.get_task_to_execute()
         task._io = io