Instead of writing down the needed cpp-files manually, it just takes all the cpp-files of the current directory.

SConstruct

"""
This Auto-SConstruct takes alle *.cpp files of the current directory - the directory the SContruct is placed in.

The program name is based on the name of a file ending with '_main.cpp'.
Example: 'myprog_main.cpp' -> 'myprog'

If there is a file eding with '_test.cpp' a google testprogram is compiled with a similar naming process.
Example: 'mytest_main.cpp' -> 'mytest'

author: Tammo Behrends (2013)
"""

import os

include_files = ['.']
shared_libraries = ['m', 'gtest', 'gtest_main']
cpp_standard = ['-std=c++98', '-pedantic']
warnings = ['-Wall', '-Wextra', '-Werror']

std = Environment(
  CXXFLAGS = cpp_standard + warnings,
  CPPPATH = include_files,
  LIBS = shared_libraries
)

cpp_files = [file_name for file_name in os.listdir(".") if file_name.endswith(".cpp")]
main_cpp = [file_name for file_name in cpp_files if file_name.endswith("_main.cpp")]
test_cpp = [file_name for file_name in cpp_files if file_name.endswith("_test.cpp")]

if main_cpp and len(main_cpp) == 1:
  program_name = main_cpp[0].split('_')[0]
  std.Program(program_name + '_test', cpp_files)

if test_cpp and len(test_cpp) == 1:
  testprogram_name = test_cpp[0].split('_')[0]
  std.Program(program_name, cpp_files)