Tests: Consolidate detection of 'rpmbuild'

Several tests use slight variations of the same logic to enable CPack
RPM tests.  Consolidate this logic into one check before any tests are
added.  Look for 'rpmbuild' only on Linux and only when the test build
tree does not have spaces in the path.  In particular, this will make
the result available in time for the RunCMake.CPackRPM test to be
activated even if CMake is configured exactly once.

Tests/CMakeLists.txt

@@ -102,6 +102,17 @@ if(BUILD_TESTING)
     list(APPEND build_options -DCMAKE_MAKE_PROGRAM:FILEPATH=${CMake_TEST_EXPLICIT_MAKE_PROGRAM})
   endif()
 
+  # Look for rpmbuild to use for tests.
+  # The tool does not work with spaces in the path.
+  if (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT CMAKE_CURRENT_BINARY_DIR MATCHES " ")
+    find_program(RPMBUILD_EXECUTABLE NAMES rpmbuild)
+  else()
+    set(RPMBUILD_EXECUTABLE "RPMBUILD_EXECUTABLE-NOTFOUND")
+  endif()
+
+  #---------------------------------------------------------------------------
+  # Add tests below here.
+
   if(NOT CMake_TEST_EXTERNAL_CMAKE)
     add_subdirectory(CMakeLib)
   endif()
@@ -826,11 +837,8 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
   set(CTEST_package_X11_TEST ${CTEST_TEST_CPACK})
   set(CTEST_RUN_CPackComponentsForAll ${CTEST_TEST_CPACK})
 
-  if (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT CMAKE_CURRENT_BINARY_DIR MATCHES " ")
-    find_program(RPMBUILD NAMES rpmbuild)
-  endif()
   # Do not try to build RPM
-  if (NOT RPMBUILD)
+  if (NOT RPMBUILD_EXECUTABLE)
     set(CPACK_BINARY_RPM OFF)
   endif()
 
@@ -912,7 +920,6 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
   if(CTEST_RUN_CPackComponentsForAll)
     # Check whether if rpmbuild command is found
     # before adding RPM tests
-    find_program(RPMBUILD_EXECUTABLE NAMES rpmbuild)
     if(RPMBUILD_EXECUTABLE)
       list(APPEND ACTIVE_CPACK_GENERATORS RPM)
     endif()
@@ -931,11 +938,9 @@ ${CMake_BINARY_DIR}/bin/cmake -DDIR=dev -P ${CMake_SOURCE_DIR}/Utilities/Release
     if(APPLE)
       list(APPEND GENLST "DragNDrop")
     endif()
-    if (NOT CMAKE_CURRENT_BINARY_DIR MATCHES " ")
-      list(FIND ACTIVE_CPACK_GENERATORS "RPM" RPM_ACTIVE)
-      if (NOT ${RPM_ACTIVE} EQUAL -1)
-        list(APPEND GENLST "RPM")
-      endif()
+    list(FIND ACTIVE_CPACK_GENERATORS "RPM" RPM_ACTIVE)
+    if (NOT ${RPM_ACTIVE} EQUAL -1)
+      list(APPEND GENLST "RPM")
     endif()
     list(FIND ACTIVE_CPACK_GENERATORS "DEB" DEB_ACTIVE)
     if (NOT ${DEB_ACTIVE} EQUAL -1)

Tests/RunCMake/CMakeLists.txt

@@ -195,6 +195,6 @@ add_RunCMake_test(IfacePaths_INCLUDE_DIRECTORIES TEST_DIR IfacePaths)
 set(IfacePaths_SOURCES_ARGS -DTEST_PROP=SOURCES)
 add_RunCMake_test(IfacePaths_SOURCES TEST_DIR IfacePaths)
 
-if(RPMBUILD)
+if(RPMBUILD_EXECUTABLE)
   add_RunCMake_test(CPackRPM)
 endif()