A new version of CollectionsTests was added to project The Inbox:
http://source.squeak.org/inbox/CollectionsTests-jar.349.mcz==================== Summary ====================
Name: CollectionsTests-jar.349
Author: jar
Time: 8 February 2021, 8:25:19.407373 pm
UUID: f484ba2b-2035-b046-9222-c3e4e42a7ad4
Ancestors: CollectionsTests-ul.348
Test to show differing SharedQueue and SharedQueue2 semantics
=============== Diff against CollectionsTests-ul.348 ===============
Item was added:
+ ----- Method: AbstractSharedQueueTest>>testContention2 (in category 'tests') -----
+ testContention2
+ "and here's a test case that distunguishes SharedQueue from SharedQueue2 semantics:
+ SharedQueue2 produces a sequence #(5 10 15) while SharedQueue produces #(5 15 10)"
+
+ | q r1 r2 r3 |
+ q := self queueClass new.
+
+ [ r1 := q next. q nextPut: 15. r3 := q next ] fork.
+ [ r2 := q next ] fork.
+
+ Processor yield. "let the above two threads block"
+
+ q nextPut: 5.
+ Processor yield. "let the first thread above proceed"
+
+ q nextPut: 10.
+ Processor yield. "let the unfinished thread above finish"
+
+ q class = SharedQueue2 ifTrue: [
+ self assert: 5 equals: r1.
+ self assert: 10 equals: r2.
+ self assert: 15 equals: r3.
+ self assert: nil equals: q nextOrNil ].
+
+ q class = SharedQueue ifTrue: [
+ self assert: 5 equals: r1.
+ self assert: 15 equals: r2.
+ self assert: 10 equals: r3.
+ self assert: nil equals: q nextOrNil ].
+
+ "SharedQueue2 implementation using a Monitor checks the queue for available data while
+ the SharedQueue implementation based on a Semaphore checks for excessSignals > 0,
+ which results in these two different outcomes"!
Locked
