BUG: Seven ImageProcessing tests never run under ctest because their names contain a semicolon #1898

Problem

Seven ImageProcessing test cases never run under ctest, and ctest reports them as passed. Their names contain a
semicolon, and test discovery splits each name at the semicolon into two ctest entries. Neither entry matches a test
case, so Catch2 runs nothing and exits successfully.

• Expected: every visible test case is registered with ctest under its full name and runs.
• Actual: each of these cases becomes two entries such as
  ImageProcessing::BinaryMorphologicalClosingImageFilter: Computed-expected (safeBorder=false and
  both algorithm paths). Both print No test cases matched and pass in about 0.02 s.

Occurs on develop at f58acc1. The affected test cases:

• BinaryMorphologicalClosingImageFilterTest.cpp L38 and L104
• ContourEngineTest.cpp L648
• GrayscaleMorphologicalOpeningImageFilterTest.cpp L18
• GrayscaleMorphologicalClosingImageFilterTest.cpp L18
• WhiteTopHatImageFilterTest.cpp L18
• BlackTopHatImageFilterTest.cpp L18

Steps to Reproduce

1. Configure a build with SIMPLNX_BUILD_TESTS=ON and build ImageProcessingUnitTest.
2. List the registered tests: ctest --test-dir "<build-dir>" -N -R "safeBorder=false$|both algorithm paths\)$|labels differ\)$".
   The list shows the name fragments, not the full names.
3. Ask ctest for one full name:
   ctest --test-dir "<build-dir>" -R "^ImageProcessing::BinaryMorphologicalClosingImageFilter: Computed-expected \(safeBorder=false; both algorithm paths\)$" --no-tests=error.
   ctest finds no test.
4. Run one fragment with -V: the command passes " both algorithm paths)" to the executable, Catch2 prints
   No test cases matched, and ctest reports Passed.

Cause

cmake/Plugin.cmake L410 registers the plugin tests with
catch_discover_tests(${UNIT_TEST_TARGET}). In Catch2 2.13.6, the discovery script CatchAddTests.cmake (in the
vcpkg Catch2 package) turns the output of --list-test-names-only into a CMake list and registers one test per
element:

string(REPLACE "\n" ";" output "${output}")
...
foreach(line ${output})

A semicolon is the CMake list separator, so a test name that contains ; becomes two list elements. The script
escapes ,, [ and ] in the test spec it passes to the executable, but nothing protects ;.

Verification Unit Test

The existing test cases are the verification; no new test is needed. For example, from
src/Plugins/ImageProcessing/test/BinaryMorphologicalClosingImageFilterTest.cpp:

TEST_CASE("ImageProcessing::BinaryMorphologicalClosingImageFilter: Computed-expected (safeBorder=false; both algorithm paths)",
          "[ImageProcessing][BinaryMorphologicalClosingImageFilter]")

Command that should run it (in-core Release build of develop, macOS arm64):

ctest --test-dir "<build-dir>" -R "^ImageProcessing::BinaryMorphologicalClosingImageFilter: Computed-expected \(safeBorder=false; both algorithm paths\)$" -j 1 --output-on-failure --timeout 300 --no-tests=error

Observed:

No tests were found!!!
Errors while running CTest

And the fragment that ctest does run:

203: Test command: .../Bin/ImageProcessingUnitTest " both algorithm paths)"
203: No test cases matched 'both algorithm paths)'
1/1 Test #203:  both algorithm paths) ...........   Passed    0.02 sec

Proposed Fix

1. Replace the ; in the seven test names with , (for example
   Computed-expected (safeBorder=false, both algorithm paths)). Run the seven tests afterwards: they have not run
   under ctest, so they may fail.
2. Keep it from coming back: add a rule to docs/Code_Style_Guide.md (Testing) that a test case name contains no
   ;, and optionally a CMake check after discovery that fails when a registered name does not match a test case.

Notes

• Found while checking the test registration for DOC: Add coding rules, a knowledge base and a shared AGENTS.md #1889; that pull request does not change
  this behavior (its split discovery registers the same names).
• One SimplnxOoc test case has the same problem.
• Test names with commas, brackets or parentheses register correctly.