Create taskhandler.py

Author: learning-zone

task_handler/taskhandler.py

@@ -0,0 +1,120 @@
+import unittest
+import sys
+from StringIO import StringIO
+
+
+class TaskHandler(object):
+
+    def __init__(self):
+
+        """
+        Ships must dock first, then vessel can be unloaded, then a truck can
+        load a container, and lastly it needs to go through a customs check.
+        The refueling process can happen anytime after a ship docks.
+        """
+
+        self._task_order = {'RE-FUELING SHIP': ['SHIP DOCKING'],
+                            'UNLOADING VESSEL': ['SHIP DOCKING'],
+                            'TRUCK LOADING CONTAINER': ['UNLOADING VESSEL'],
+                            'CUSTOMS CHECK': ['TRUCK LOADING CONTAINER']
+                           }
+
+
+        self.task_list = {'SHIP DOCKING': 0,
+                          'RE-FUELING SHIP': 0,
+                          'UNLOADING VESSEL': 0,
+                          'TRUCK LOADING CONTAINER': 0,
+                          'CUSTOMS CHECK': 0
+                         }
+
+
+    def tasks_remaining(self):
+        """ Gets total number of tasks remaining. """
+
+        return sum(self.task_list.values())
+
+
+    def add_task(self, tasks_array):
+        """ Adds an array of tasks to existing task list. """
+
+        for task_file in tasks_array:
+            task = open(task_file).read().rstrip()
+            self.task_list[task] = self.task_list.get(task) + 1
+
+
+    def execute_tasks(self):
+        """ Executes tasks in sensible order. """
+
+        for task in self.task_list.keys():
+
+            if task not in self._task_order:
+                while self.task_list[task] > 0:
+                    print task + ' COMPLETED'
+                    self.remove_task(task)
+
+            else:
+                while self.task_list[task] > 0:
+                    self.check_dependencies(task)
+                    print task + ' COMPLETED'
+                    self.remove_task(task)
+
+
+
+    def check_dependencies(self, task):
+        """ Checks for any task dependencies. """
+
+        dependencies_remaining = []
+
+        if task in self._task_order:
+            dependencies = self._task_order[task]
+
+            for dependency in dependencies:
+                dependencies_remaining.append(dependency)
+
+        if dependencies_remaining == []:
+            return
+        else:
+            for dependency in dependencies_remaining:
+                self.check_dependencies(dependency)
+
+
+
+    def remove_task(self, task):
+        """ Removes a task from the task list once it has been completed. """
+
+        self.task_list[task] -= 1
+
+
+    def __repr__(self):
+
+        return '<{} tasks remaining>'.format(self.tasks_remaining())
+
+
+
+class TestingTaskHandler(unittest.TestCase):
+
+    def setUp(self):
+        self.job = TaskHandler()
+        self.job.add_task(['task0.py', 'task1.py', 'task4.py', 'task2.py', 'task3.py', 'task3.py', 'task4.py', 'task2.py', 'task1.py'])
+        self.held = sys.stdout
+        sys.stdout = StringIO()
+
+    def test_add_tasks(self):
+        self.assertEqual(self.job.tasks_remaining(), 9)
+        self.assertEqual(self.job.task_list, {'SHIP DOCKING': 1, 'UNLOADING VESSEL': 2, 'CUSTOMS CHECK': 2, 'TRUCK LOADING CONTAINER': 2, 'RE-FUELING SHIP': 2})
+
+    def test_remove_task(self):
+        self.job.remove_task('SHIP DOCKING')
+        self.assertEqual(self.job.tasks_remaining(), 8)
+        self.assertEqual(self.job.task_list, {'SHIP DOCKING': 0, 'UNLOADING VESSEL': 2, 'CUSTOMS CHECK': 2, 'TRUCK LOADING CONTAINER': 2, 'RE-FUELING SHIP': 2})
+
+    def test_execute_tasks(self):
+        self.job.execute_tasks()
+        self.assertEqual(self.job.tasks_remaining(), 0)
+        self.assertEqual(sys.stdout.getvalue(),
+            'SHIP DOCKING COMPLETED\nUNLOADING VESSEL COMPLETED\nUNLOADING VESSEL COMPLETED\nCUSTOMS CHECK COMPLETED\nCUSTOMS CHECK COMPLETED\nTRUCK LOADING CONTAINER COMPLETED\nTRUCK LOADING CONTAINER COMPLETED\nRE-FUELING SHIP COMPLETED\nRE-FUELING SHIP COMPLETED\n')
+
+
+
+if __name__ == '__main__':
+    unittest.main()