SyntaxConformanceTest::testSqlOperators - Skip "Dedupe" entity on MySQL 5.5

[totten]

Overview

This disables a particularly flaky test-scenario.

Technical Details

The SyntaxConformanceTest::testSqlOperators() has been rather flaky for a while. (I think this goes back either to the creation of the test or the expansion of Dedupe API -- in other words, the test of this scenario has always been flaky.)

When the test fails, it looks like this:

api_v3_SyntaxConformanceTest::testSqlOperators with data set #28 ('Dedupe')
incorrect count returned from Dedupe getcount
Failed asserting that 0 matches expected 2.

/home/jenkins/bknix-min/build/build-1/web/sites/all/modules/civicrm/Civi/Test/Api3TestTrait.php:191
/home/jenkins/bknix-min/build/build-1/web/sites/all/modules/civicrm/tests/phpunit/api/v3/SyntaxConformanceTest.php:1131
/home/jenkins/bknix-min/build/build-1/web/sites/all/modules/civicrm/tests/phpunit/CiviTest/CiviUnitTestCase.php:215
/home/jenkins/bknix-min/civicrm-buildkit/extern/phpunit6/phpunit6.phar:570

I've spent a chunk of time investigating the flakiness and found:

1. The version of PHP (php70 vs php72) did not make much difference.
2. The test usually (possibly always?) passed on MySQL 5.7.
3. The test often (but not always) failed on MySQL 5.5.
4. The test never failed when run by itself. The smallest scenario which seemed to reliably produce the failure was:

    env
      SYNTAX_CONFORMANCE_ENTITIES='ContactType Country Dedupe Domain StateProvince' \
      CIVICRM_UF=UnitTests \
      phpunit5 \
      --stop-on-failure --tap \
      tests/phpunit/api/v3/SyntaxConformanceTest.php \
      --filter '(testCustomDataGet|testLimit|testSqlOperators)'
   

5. The reproducibility differed on two laptops. The laptops were largely identical wrt PHP/MySQL binaries+configuration (macOS, bknix@master-loco, min cfg). They differed (nominally) in host OS and (significantly) in hardware specs. The slower machine (low-wattage 2-core CPU; 8gb; Mojave) produced test-failures much more reliably than the faster machine (high-wattage 4-core CPU; 16gb; Sierra).

Rationalizations for why it's OK to skip:

• The test will continue to be monitored on MySQL 5.7+.
• The test does pass reliably when run by itself on MySQL 5.5.
• Civi doesn't officially support MySQL 5.5, so we're not required to faff-about over a failure that only occurs on MySQL 5.5.

See also: https://chat.civicrm.org/civicrm/pl/s7nbkro8yjfgzk5z4epo8g9jph

[civibot]

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