Add infrastructure for CMakeCommands tests

Generalize the build_command test framework as a macro to add the
test.  Process the CMakeCommands subdirectory explicitly.

Tests/CMakeCommands/CMakeLists.txt

@@ -0,0 +1,10 @@
+macro(add_CMakeCommands_test test)
+  add_test(CMakeCommands.${test} ${CMAKE_CMAKE_COMMAND}
+    -DCMake_SOURCE_DIR=${CMake_SOURCE_DIR} # TODO: Remove
+    -Ddir=${CMAKE_CURRENT_BINARY_DIR}/${test}
+    -Dgen=${CMAKE_TEST_GENERATOR}
+    -P "${CMAKE_CURRENT_SOURCE_DIR}/${test}/test.cmake"
+    )
+endmacro()
+
+add_CMakeCommands_test(build_command)

Tests/CMakeLists.txt

@@ -48,6 +48,7 @@ IF(BUILD_TESTING)
 
   ADD_SUBDIRECTORY(CMakeLib)
   ADD_SUBDIRECTORY(CMakeOnly)
+  ADD_SUBDIRECTORY(CMakeCommands)
 
   ADD_SUBDIRECTORY(FindPackageModeMakefileTest)
 
@@ -1695,13 +1696,6 @@ ${CMake_BINARY_DIR}/bin/cmake -DVERSION=master -P ${CMake_SOURCE_DIR}/Utilities/
   add_config_tests(Release)
   add_config_tests(RelWithDebInfo)
 
-  add_test(CMakeCommands.build_command ${CMAKE_CMAKE_COMMAND}
-    -DCMake_SOURCE_DIR=${CMake_SOURCE_DIR}
-    -Ddir=${CMake_BINARY_DIR}/Tests/CMakeCommands/build_command
-    -Dgen=${CMAKE_TEST_GENERATOR}
-    -P "${CMake_SOURCE_DIR}/Tests/CMakeCommands/build_command/RunCMake.cmake"
-  )
-
   ADD_TEST_MACRO(CMakeCommands.target_link_libraries target_link_libraries)
 
   CONFIGURE_FILE(