Testing

Run all the code

• End to End <-- For clarity
• Integration
• Functional
• Situational
• Acceptance

Run from the tested code all the way down the stack
and segments of code in the middle of the stack

• Integration <-- For clarity
• Functional
• Unit

Run only the code under test (one method or function)

• Unit <-- For clarity

What's their purpose?

• Show that your software actually works.
• Where you find logic errors and high level mistakes in your code.
• ONLY tests that will actually find bugs in your code base.
• Don't change often
• Often are very similar, making them easy to write

How does that look on the stack?

What's their purpose?

• Help you write code
• You can see that new code really works on the stack
• They test how units work together...
• You don't have to test to the bottom of the stack!

How does that look on the stack?

What's their purpose?

• Changes to the code base cause them to fail
  • Mutation Testing
• Any and all possible inputs and outputs are tested
  • Trust Stack
• You no longer need to look at this code, as long as the tests pass
  • This test and all end to end tests

How does that look on the stack?

Integration

should('result in the S3 bucket files being read in chunks based ' +
  'on the selected chunk size, ignoring empty files') do
  # Given: a file on S3 with more than 5 bytes of data
  #   and less than 10 bytes, a file on S3 with no data,
  #   and an S3Implementation object with the chunk size set to 5 bytes
  s3 = S3.new
  file_path = 'test'
  s3.write(file_path + "/data", 'some data')
  s3.write(file_path + "/nodata", '')

  s3_implementation = S3Implementation.new(file_path)
  s3_implementation.chunk_size = 5

  # When: we iterate over the data with the s3_implementation object
  count = 0
  s3_implementation.each do |chunk|
    count += 1
  end

  # Then: we should see 2 chunks: 2 for the file with more than 5 bytes,
  #   and none for the empty file
  assert_equal(2, count)
end

Unit

should('set s3 chunk_size property') do
    # Given: a value to set the chunk_size to and an S3Implementation
    chunk_size = 9000
    s3_implementation = S3Implementation.new('test')

    # When: we set the chunk size to the new value
    s3_implementation.chunk_size = chunk_size

    # We should see that the S3 base object has the new chunk size
    assert_equal chunk_size, s3_implementation.send(:s3).chunk_size
  end