Update Test.

Author: jverswijver

datajoint/expression.py

@@ -439,17 +439,11 @@ def tail(self, limit=25, **fetch_kwargs):
 
     def __len__(self):
         """:return: number of elements in the result set e.g. ``len(q1)``."""
-        try:
-            if self._left[0]:
-                return self.connection.query(
-                    'SELECT distinct count(*) FROM {from_}{where}'.format(
-                        from_=self.from_clause(),
-                        where=self.where_clause())).fetchone()[0]
-        except IndexError:
-            pass
         return self.connection.query(
-            'SELECT count(DISTINCT {fields}) FROM {from_}{where}'.format(
-                fields=self.heading.as_sql(self.primary_key, include_aliases=False),
+            'SELECT {select_} FROM {from_}{where}'.format(
+                select_=('DISTINCT count(*)' if any(self._left)
+                         else 'count(DISTINCT {fields})'.format(fields=self.heading.as_sql(
+                            self.primary_key, include_aliases=False))),
                 from_=self.from_clause(),
                 where=self.where_clause())).fetchone()[0]
 

tests/test_aggr_regressions.py

@@ -8,6 +8,8 @@
 from . import PREFIX, CONN_INFO
 import datetime
 import numpy as np
+import uuid
+from .schema_uuid import Topic, Item, top_level_namespace_id
 schema = dj.Schema(PREFIX + '_aggr_regress', connection=dj.conn(**CONN_INFO))
 
 # --------------- ISSUE 386 -------------------
@@ -95,38 +97,6 @@ class X(dj.Lookup):
     contents = zip(range(10))
 
 
-@schema
-class Parent(dj.Manual):
-    definition = """
-    # Parent table
-    id: int
-    ---
-    txt = "NA" : varchar(32)
-    """
-
-
-@schema
-class Child(dj.Computed):
-    definition = """
-    # Child table
-    -> Parent
-    start_time: datetime(6)
-    ---
-    timestamps: longblob
-    """
-
-    def make(self, key):
-        t = np.random.poisson(1000, 10)
-        t.sort()
-        self.insert1(
-            {
-                "start_time": datetime.datetime.now(),
-                "timestamps": t,
-                **key,
-            }
-        )
-        print(f"ingested w/ {key}")
-
 def test_issue558_part1():
     q = (A-B).proj(id2='3')
     assert_equal(len(A - B), len(q))
@@ -138,9 +108,11 @@ def test_issue558_part2():
 
 
 def test_left_join_len():
-    Parent.insert1({"id": 1})
-    Child.populate()
-    Parent.insert([{"id": 2}, {"id": 3}, {"id": 4}])
-    q = Parent.join(Child & "id != 1", left=True)
+    Topic().add('jeff')
+    Item.populate()
+    Topic().add('jeff2')
+    Topic().add('jeff3')
+    q = Topic.join(Item - dict(topic_id=uuid.uuid5(top_level_namespace_id, 'jeff')),
+                   left=True)
     qf = q.fetch()
     assert len(q) == len(qf)