Add CTestLimitDashJ test (#12904)

Add a test that verifies that when ctest -j 4 is called, at most, 4 tests
are executed at any one time.

The test works by running the same script as each of 100 tests. And then setting
up test properties for DEPENDS, RUN_SERIAL, PROCESSORS and COST in order to get
the tests to run in a semi-deterministic ordering, even in parallel. The script
writes a file, sleeps for a bit, and then deletes the file. In the meantime, it
counts files that currently exist, and emits output that triggers a test failure
if the count of files is ever greater than 4.

Prior to the commit that fixed bug #12904, this would result in a failed test
because the output of some of the tests would indicate that more than 4 tests
were running simultaneously.

Now that this issue is resolved, this test will help guarantee that it stays
resolved moving forward.

1 files changed, 48 insertions, 0 deletions

diff --git a/Tests/CTestLimitDashJ/CreateSleepDelete.cmake b/Tests/CTestLimitDashJ/CreateSleepDelete.cmake
new file mode 100644
index 0000000..b09307f
--- /dev/null
+++ b/Tests/CTestLimitDashJ/CreateSleepDelete.cmake
@@ -0,0 +1,48 @@
+set(CTEST_RUN_CURRENT_SCRIPT 0)
+
+if(NOT DEFINED basefilename)
+  message(FATAL_ERROR "pass -Dbasefilename=f1")
+endif()
+
+if(NOT DEFINED ext)
+  set(ext "jkqvxz")
+endif()
+
+if(NOT DEFINED sleep_interval)
+  set(sleep_interval 1)
+endif()
+
+get_filename_component(self_dir "${CMAKE_CURRENT_LIST_FILE}" PATH)
+set(filename "${self_dir}/${basefilename}.${ext}")
+
+# count files
+file(GLOB f1 *.${ext})
+list(LENGTH f1 c1)
+message("c='${c1}'")
+
+# write a new file
+message("Writing file: filename='${filename}'")
+file(WRITE "${filename}" "${filename}")
+
+# count files again
+file(GLOB f2 *.${ext})
+list(LENGTH f2 c2)
+message("c='${c2}'")
+
+# snooze
+message("Sleeping: sleep_interval='${sleep_interval}'")
+ctest_sleep(${sleep_interval})
+
+# count files again
+file(GLOB f3 *.${ext})
+list(LENGTH f3 c3)
+message("c='${c3}'")
+
+# delete the file we wrote earlier
+message("Removing file: filename='${filename}'")
+file(REMOVE "${filename}")
+
+# count files again
+file(GLOB f4 *.${ext})
+list(LENGTH f4 c4)
+message("c='${c4}'")