Simple C++ program with Google test

I have little to no experience with unit testing.  I want to change that.

In principle, unit testing sounds simple.  Unit tests are used to isolate and validate small parts of a program are working.  In practice, I don't really know how it's done.

As a first attempt, I tried to build a simple program with tests using google test, https://code.google.com/p/googletest/.  After downloading and unzipping the library, I moved it into a folder -- SomeDirectory/libs/gtest-1.6.0.  I then copied these files into a separate directory.

• Makefile -- this is used by make to build both the test program and my program.
• sample1.h, sample1.cc -- These define some functions that are linked into the test program and into my program.
• sample_unittest.cc -- This defines test macros that are run in the test program.

If you put these files into a directory, you are almost ready to run the test.  You will have to update the paths in the Makefile.

• GTEST_DIR = SomeDirectory/libs/gtest-1.6.0
• USER_DIR = ./ 

You can run then run "make" followed by "sample1_unittest" and you should see some successful test output.

I wanted to add a real program with this test suite, so I wrote this:
To build the program I updated the Makefile to build "my_program" like this:
TESTS = sample1_unittest my_program

and then I added this to the end of the Makefile:

my_program : sample1.o main.o 

$(CXX) $(CPPFLAGS) $(CXXFLAGS) -lpthread $^ -o $@

After running make, I had two programs.  "sample1_unittest" was the original test program and "my_program" was the 'real' program that I was testing.