tests: Switch from PYTHON_EXECUTABLE to PYTHON_DEFAULT_EXECUTABLE

The DetectPython cmake script now outputs a default python executable.
Updated other cmake scripts to use this concept.  Used default where
python2/3 will work, use explicit PYTHON2/3_EXECUTABLE where an
explicit version is needed.  Also, fail if python is required and NO
version of python was found.

Signed-off-by: Noel Eck <noel.eck@intel.com>

CMakeLists.txt

@@ -54,11 +54,23 @@ if (BUILDSWIGPYTHON OR BUILDSWIGNODE OR BUILDSWIGJAVA)
   include (${SWIG_USE_FILE})
 endif ()
 
-# Python is required for swig generated python and for UPM tests
+# Python is required for swig generated python and for UPM tests.
-# UPM build can generated modules for both python2 AND python3
+# The UPM build can generated modules for both python2 AND python3
+# with the corresponding PYTHONLIBS.  Currently, BUILDTESTS has a
+# hard dependency on the PYTHON2INTERP.
 # OpenCV python detect will attempt to find python2/3
 if (BUILDSWIGPYTHON OR BUILDTESTS)
   include (cmake/modules/OpenCVDetectPython.cmake)
+
+  # Fail if building tests but no python interpreter was found
+  if (BUILDTESTS AND NOT PYTHON2INTERP_FOUND)
+      message(FATAL_ERROR "BUILDTESTS=ON requires the python2 interpreter")
+  endif (BUILDTESTS AND NOT PYTHON2INTERP_FOUND)
+
+  # Fail if no LIBS were found
+  if (NOT PYTHON2LIBS_FOUND AND NOT PYTHON3LIBS_FOUND)
+      message(FATAL_ERROR "At least one python lib is required")
+  endif (NOT PYTHON2LIBS_FOUND AND NOT PYTHON3LIBS_FOUND)
 endif (BUILDSWIGPYTHON OR BUILDTESTS)
 
 # Which versions of python were found?

src/CMakeLists.txt

@@ -442,7 +442,7 @@ endmacro(upm_module_init)
 if (BUILDDOC AND BUILDSWIGPYTHON)
   # doxy2swig the doxygen output
   add_custom_target (pyupm_doxy2swig ALL
-    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/doxy2swig.py
+    COMMAND ${PYTHON2_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/doxy2swig.py
       ${CMAKE_BINARY_DIR}/xml/index.xml
       ${CMAKE_CURRENT_BINARY_DIR}/pyupm_doxy2swig.i
       DEPENDS doc)

tests/CMakeLists.txt

@@ -1,55 +1,65 @@
-add_test (NAME check_consistency COMMAND ${PYTHON_EXECUTABLE}
+# Add some general tests (which use python2)...
+if (PYTHON_DEFAULT_AVAILABLE)
+    # Consistency check
+    add_test (NAME check_consistency COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_consistency.py
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
 
-# Check file encodings in src tree
+    # Check file encodings in src tree
-if (PYTHON2INTERP_FOUND)
+    add_test (NAME check_file_encoding COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
-    add_test (NAME check_file_encoding COMMAND ${PYTHON_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_file_encoding.py
         WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/src)
-endif (PYTHON2INTERP_FOUND)
+endif (PYTHON_DEFAULT_AVAILABLE)
 
-if (BUILDSWIGJAVA)
+# Add some java tests
-    add_test (NAME check_autoloadlibrary COMMAND ${PYTHON_EXECUTABLE}
+if (BUILDSWIGJAVA AND PYTHON_DEFAULT_AVAILABLE)
+    add_test (NAME check_autoloadlibrary COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_autoloadlibrary.py
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
 
-    add_test (NAME check_examplenames_java COMMAND ${PYTHON_EXECUTABLE}
+    add_test (NAME check_examplenames_java COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_examplenames.py java
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
 
-    add_test (NAME check_clean COMMAND ${PYTHON_EXECUTABLE}
+    add_test (NAME check_clean COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_clean.py
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
-endif ()
+endif (BUILDSWIGJAVA AND PYTHON_DEFAULT_AVAILABLE)
 
-if (BUILDSWIGNODE)
+# Add a node test
-    add_test (NAME check_examplenames_js COMMAND ${PYTHON_EXECUTABLE}
+if (BUILDSWIGNODE AND PYTHON_DEFAULT_AVAILABLE)
+    add_test (NAME check_examplenames_js COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_examplenames.py js
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
-endif (BUILDSWIGNODE)
+endif (BUILDSWIGNODE AND PYTHON_DEFAULT_AVAILABLE)
 
-if (BUILDSWIGPYTHON)
+# Add a python test
-    add_test (NAME check_examplenames_python COMMAND ${PYTHON_EXECUTABLE}
+if (BUILDSWIGPYTHON AND PYTHON_DEFAULT_AVAILABLE)
+    # Check python examples against cxx examples
+    add_test (NAME check_examplenames_python COMMAND ${PYTHON_DEFAULT_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_examplenames.py python
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+endif (BUILDSWIGPYTHON AND PYTHON_DEFAULT_AVAILABLE)
 
-    if (PYTHON2INTERP_FOUND)
+# Add some python2 tests
+if (BUILDSWIGPYTHON AND PYTHON2INTERP_FOUND)
+    # Test load python2 modules
     add_test (NAME check_load_modules_python2 COMMAND ${PYTHON2_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_pythonload.py
         ${CMAKE_BINARY_DIR}/src/*/python${PYTHON2_VERSION_MAJOR}.${PYTHON2_VERSION_MINOR}/*.py
         WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/src/)
 
+    # Test load examples w/python2
     add_test (NAME check_load_examples_python2 COMMAND ${PYTHON2_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_pythonload.py
         ${CMAKE_SOURCE_DIR}/examples/python/*.py
         WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/src/)
-    endif (PYTHON2INTERP_FOUND)
+endif (BUILDSWIGPYTHON AND PYTHON2INTERP_FOUND)
 
-    if (PYTHON3INTERP_FOUND)
+# Add a python3 test
+if (BUILDSWIGPYTHON AND PYTHON3INTERP_FOUND)
     add_test (NAME check_load_modules_python3 COMMAND ${PYTHON3_EXECUTABLE}
         ${CMAKE_CURRENT_SOURCE_DIR}/check_pythonload.py
         ${CMAKE_BINARY_DIR}/src/*/python${PYTHON3_VERSION_MAJOR}.${PYTHON3_VERSION_MINOR}/*.py
         WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/src/)
-    endif (PYTHON3INTERP_FOUND)
+endif (BUILDSWIGPYTHON AND PYTHON3INTERP_FOUND)
-endif (BUILDSWIGPYTHON)