I did a 'guix system build' of my Plasma configuration ahead of actually
installing it and got the following build failure:

phase `install' succeeded after 15.5 seconds
starting phase `check-after-install'
Test project /tmp/guix-build-plasma-workspace-5.25.5.drv-0/build
      Start  1: kworkspace-testPlatformDetection
 1/14 Test  #1: kworkspace-testPlatformDetection ...   Passed    0.01 sec
      Start  2: tasktoolstest
 2/14 Test  #2: tasktoolstest ......................   Passed    0.05 sec
      Start  3: launchertasksmodeltest
 3/14 Test  #3: launchertasksmodeltest .............   Passed    0.11 sec
      Start  4: screenpooltest
 4/14 Test  #4: screenpooltest .....................***Exception: SegFault  2.52 sec
********* Start testing of ScreenPoolTest *********
Config: Using QtTest library 5.15.8, Qt 5.15.8 (x86_64-little_endian-lp64 shared (dynamic) release b
uild; by GCC 11.3.0), unknown unknown
PASS   : ScreenPoolTest::initTestCase()
PASS   : ScreenPoolTest::testScreenInsertion()
PASS   : ScreenPoolTest::testRedundantScreenInsertion()
PASS   : ScreenPoolTest::testMoveOutOfRedundant()
PASS   : ScreenPoolTest::testMoveInRedundant()
PASS   : ScreenPoolTest::testPrimarySwap()
PASS   : ScreenPoolTest::testPrimarySwapToRedundant()
PASS   : ScreenPoolTest::testMoveRedundantToMakePrimary()
PASS   : ScreenPoolTest::testMoveInRedundantToLosePrimary()
PASS   : ScreenPoolTest::testSecondScreenRemoval()
PASS   : ScreenPoolTest::testThirdScreenRemoval()
QINFO  : ScreenPoolTest::testLastScreenRemoval() qt.qpa.wayland: Creating a fake screen in order for
 Qt not to crash
PASS   : ScreenPoolTest::testLastScreenRemoval()
PASS   : ScreenPoolTest::testFakeToRealScreen()
PASS   : ScreenPoolTest::cleanupTestCase()
Totals: 14 passed, 0 failed, 0 skipped, 0 blacklisted, 2399ms
********* Finished testing of ScreenPoolTest *********

      Start  5: klipper-testHistory
 5/14 Test  #5: klipper-testHistory ................   Passed    0.03 sec
      Start  6: klipper-testHistoryModel
 6/14 Test  #6: klipper-testHistoryModel ...........   Passed    0.04 sec
      Start  7: klipper-testUtils
 7/14 Test  #7: klipper-testUtils ..................   Passed    0.03 sec
      Start  8: testChromeBookmarks
 8/14 Test  #8: testChromeBookmarks ................   Passed    0.05 sec
      Start  9: testFirefoxBookmarks
 9/14 Test  #9: testFirefoxBookmarks ...............   Passed    0.10 sec
      Start 10: testBookmarksMatch
10/14 Test #10: testBookmarksMatch .................   Passed    0.04 sec
      Start 11: calculatorrunnertest
11/14 Test #11: calculatorrunnertest ...............   Passed    0.08 sec
      Start 12: locationsrunnertest
12/14 Test #12: locationsrunnertest ................   Passed    0.28 sec
      Start 13: servicerunnertest
13/14 Test #13: servicerunnertest ..................   Passed    0.26 sec
      Start 14: shellrunnertest
14/14 Test #14: shellrunnertest ....................   Passed    0.10 sec

93% tests passed, 1 tests failed out of 14

Total Test time (real) =   3.71 sec

The following tests FAILED:
          4 - screenpooltest (SEGFAULT)
Errors while running CTest
error: in phase 'check-after-install': uncaught exception:
%exception #<&invoke-error program: "ctest" arguments: ("-E" "(appstreamtest|lookandfeel-kcmTest|tst
_triangleFilter|systemtraymodeltest|testdesktop| screenpooltest)") exit-status: 8 term-signal: #f st
op-signal: #f> 
phase `check-after-install' failed after 3.7 seconds
command "ctest" "-E" "(appstreamtest|lookandfeel-kcmTest|tst_triangleFilter|systemtraymodeltest|test
desktop| screenpooltest)" failed with status 8
builder for `/gnu/store/ims94hwcfi3wjsxqz89vr8xhr2shxm3d-plasma-workspace-5.25.5.drv' failed with ex
it code 1
build of /gnu/store/ims94hwcfi3wjsxqz89vr8xhr2shxm3d-plasma-workspace-5.25.5.drv failed
View build log at '/var/log/guix/drvs/im/s94hwcfi3wjsxqz89vr8xhr2shxm3d-plasma-workspace-5.25.5.drv.
gz'.
guix system: error: build of `/gnu/store/ims94hwcfi3wjsxqz89vr8xhr2shxm3d-plasma-workspace-5.25.5.dr
v' failed