Adopt 'src' layout and add 'testing' extras

src/xdist/scheduler/each.py

@@ -0,0 +1,132 @@
+from py.log import Producer
+
+from xdist.workermanage import parse_spec_config
+from xdist.report import report_collection_diff
+
+
+class EachScheduling(object):
+    """Implement scheduling of test items on all nodes
+
+    If a node gets added after the test run is started then it is
+    assumed to replace a node which got removed before it finished
+    its collection.  In this case it will only be used if a node
+    with the same spec got removed earlier.
+
+    Any nodes added after the run is started will only get items
+    assigned if a node with a matching spec was removed before it
+    finished all its pending items.  The new node will then be
+    assigned the remaining items from the removed node.
+    """
+
+    def __init__(self, config, log=None):
+        self.config = config
+        self.numnodes = len(parse_spec_config(config))
+        self.node2collection = {}
+        self.node2pending = {}
+        self._started = []
+        self._removed2pending = {}
+        if log is None:
+            self.log = Producer("eachsched")
+        else:
+            self.log = log.eachsched
+        self.collection_is_completed = False
+
+    @property
+    def nodes(self):
+        """A list of all nodes in the scheduler."""
+        return list(self.node2pending.keys())
+
+    @property
+    def tests_finished(self):
+        if not self.collection_is_completed:
+            return False
+        if self._removed2pending:
+            return False
+        for pending in self.node2pending.values():
+            if len(pending) >= 2:
+                return False
+        return True
+
+    @property
+    def has_pending(self):
+        """Return True if there are pending test items
+
+        This indicates that collection has finished and nodes are
+        still processing test items, so this can be thought of as
+        "the scheduler is active".
+        """
+        for pending in self.node2pending.values():
+            if pending:
+                return True
+        return False
+
+    def add_node(self, node):
+        assert node not in self.node2pending
+        self.node2pending[node] = []
+
+    def add_node_collection(self, node, collection):
+        """Add the collected test items from a node
+
+        Collection is complete once all nodes have submitted their
+        collection.  In this case its pending list is set to an empty
+        list.  When the collection is already completed this
+        submission is from a node which was restarted to replace a
+        dead node.  In this case we already assign the pending items
+        here.  In either case ``.schedule()`` will instruct the
+        node to start running the required tests.
+        """
+        assert node in self.node2pending
+        if not self.collection_is_completed:
+            self.node2collection[node] = list(collection)
+            self.node2pending[node] = []
+            if len(self.node2collection) >= self.numnodes:
+                self.collection_is_completed = True
+        elif self._removed2pending:
+            for deadnode in self._removed2pending:
+                if deadnode.gateway.spec == node.gateway.spec:
+                    dead_collection = self.node2collection[deadnode]
+                    if collection != dead_collection:
+                        msg = report_collection_diff(
+                            dead_collection,
+                            collection,
+                            deadnode.gateway.id,
+                            node.gateway.id,
+                        )
+                        self.log(msg)
+                        return
+                    pending = self._removed2pending.pop(deadnode)
+                    self.node2pending[node] = pending
+                    break
+
+    def mark_test_complete(self, node, item_index, duration=0):
+        self.node2pending[node].remove(item_index)
+
+    def remove_node(self, node):
+        # KeyError if we didn't get an add_node() yet
+        pending = self.node2pending.pop(node)
+        if not pending:
+            return
+        crashitem = self.node2collection[node][pending.pop(0)]
+        if pending:
+            self._removed2pending[node] = pending
+        return crashitem
+
+    def schedule(self):
+        """Schedule the test items on the nodes
+
+        If the node's pending list is empty it is a new node which
+        needs to run all the tests.  If the pending list is already
+        populated (by ``.add_node_collection()``) then it replaces a
+        dead node and we only need to run those tests.
+        """
+        assert self.collection_is_completed
+        for node, pending in self.node2pending.items():
+            if node in self._started:
+                continue
+            if not pending:
+                pending[:] = range(len(self.node2collection[node]))
+                node.send_runtest_all()
+                node.shutdown()
+            else:
+                node.send_runtest_some(pending)
+            self._started.append(node)