From e0377a3e92663f6ab9a8c6ffd405031db6ed0096 Mon Sep 17 00:00:00 2001
From: Bertrand Benjamin <benjamin.bertrand@opytex.org>
Date: Fri, 8 Apr 2022 21:49:18 +0200
Subject: [PATCH] Feat: scheduler handle dependencies (basic)

---
 bopytex/scheduler.py   |  9 ++++++++-
 test/test_scheduler.py | 25 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/bopytex/scheduler.py b/bopytex/scheduler.py
index db141c0..db00b12 100644
--- a/bopytex/scheduler.py
+++ b/bopytex/scheduler.py
@@ -19,12 +19,19 @@ class Scheduler:
         self._tasks += tasks
 
     def dispatch(self, task):
-        """ Do a task """
+        """Do a task"""
         ans = self.actions[task.action](task.deps, task.args)
         return ans
 
     def __next__(self):
+        undoable = []
+
         task = self._tasks.pop(0)
+        while not all([d in self.done for d in task.deps]):
+            undoable.append(task)
+            task = self._tasks.pop(0)
+
+        self.append(undoable)
         ans = self.dispatch(task)
         self._done.append(ans)
         return ans
diff --git a/test/test_scheduler.py b/test/test_scheduler.py
index 183a878..a79c764 100644
--- a/test/test_scheduler.py
+++ b/test/test_scheduler.py
@@ -59,3 +59,28 @@ def test_schedule_multiple_tasks():
     assert result == "three done"
     assert scheduler.tasks == []
     assert scheduler.done == ["one done", "two done", "three done"]
+
+
+def test_schedule_multiple_tasks_with_dependencies():
+    actions = {"DO": lambda deps, args: f"{args['task']} done"}
+    scheduler = Scheduler(actions)
+    t1 = Task(action="DO", args={"task": "one"}, deps=["three done"])
+    t2 = Task(action="DO", args={"task": "two"}, deps=["one done"])
+    t3 = Task(action="DO", args={"task": "three"}, deps=[])
+    scheduler.append([t1, t2, t3])
+
+    result = scheduler.__next__()
+    assert result == "three done"
+    assert scheduler.tasks == [t1, t2]
+    assert scheduler.done == ["three done"]
+
+    result = scheduler.__next__()
+    assert result == "one done"
+    assert scheduler.tasks == [t2]
+    assert scheduler.done == ["three done", "one done"]
+
+    result = scheduler.__next__()
+    assert result == "two done"
+    assert scheduler.tasks == []
+    assert scheduler.done == ["three done", "one done", "two done"]
+