The LocalDateTimeStringConverterTest fails on a system with a Canadian locale or any other locale that uses the suffix "p.m." to denote the 12 hours from noon until midnight.

SYSTEM / OS / JAVA RUNTIME INFORMATION

Ubuntu 20.04.2 LTS
  $ uname -srm
  Linux 5.4.0-67-generic x86_64

macOS 11.2.3 (Big Sur)
  $ uname -srm
  Darwin 20.3.0 x86_64

Microsoft Windows 10 Pro Version 10.0.19042
  $ uname -srm
  CYGWIN_NT-10.0 3.1.7(0.340/5/3) x86_64

Oracle OpenJDK 15.0.2
  $ java --version
  openjdk 15.0.2 2021-01-19
  OpenJDK Runtime Environment (build 15.0.2+7-27)
  OpenJDK 64-Bit Server VM (build 15.0.2+7-27, mixed mode, sharing)

Apache Ant 1.10.9
  $ ant -version
  Apache Ant(TM) version 1.10.9 compiled on September 27 2020

STEPS TO REPRODUCE

Simulate a Canadian locale by running the tests with:

  $ bash gradlew -Duser.country=CA test -x :web:test

EXPECTED RESULTS

The tests should be successful regardless of the locale:

  $ bash gradlew test -x :web:test
  ...
  BUILD SUCCESSFUL in 4m 16s
  192 actionable tasks: 192 executed

ACTUAL RESULT

The tests fail on a system with a Canadian locale:

  $ bash gradlew test -x :web:test
  ...
  > Task :base:test

  test.javafx.util.converter.LocalDateTimeStringConverterTest
    > toString_to_fromString_testRoundtrip[0] FAILED
    java.time.format.DateTimeParseException:
    Text '1985-01-12, 12:34 p.m.' could not be parsed,
    unparsed text found at index 19
  ...
  5311 tests completed, 1 failed, 28 skipped

  > Task :base:test FAILED

  FAILURE: Build failed with an exception.

SOURCE CODE FOR AN EXECUTABLE TEST CASE

None.

WORKAROUND

To work around the problem, run the tests with a default U.S. locale:

  $ bash gradlew -Duser.country=US test -x :web:test