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Fix test
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m-kuhn committed Aug 8, 2018
1 parent 58da975 commit bbffad6fc8390edc632425389123a8ba3af50879
Showing with 22 additions and 0 deletions.
  1. +22 −0 tests/src/python/
@@ -846,3 +846,25 @@ def testStringComparison(self):
self.assertEqual(count, 5)

def testConcurrency(self):
The connection pool has a maximum of 4 connections defined (+2 spare connections)
Make sure that if we exhaust those 4 connections and force another connection
it is actually using the spare connections and does not freeze.
This situation normally happens when (at least) 4 rendering threads are active
in parallel and one requires an expression to be evaluated.
# Acquire the maximum amount of concurrent connections
iterators = list()
for i in range(QgsApplication.instance().maxConcurrentConnectionsPerPool()):

# Run an expression that will also do a request and should use a spare
# connection. It just should not deadlock here.

feat = next(iterators[0])
context = QgsExpressionContext()
exp = QgsExpression('get_feature(\'{layer}\', \'pk\', 5)'.format(

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