What is legacy code?

Lets define "legacy code" for the purpose of this talk.

• inherited code
• created by someone in the past
• (other programmers, company)

.. or even yourself

Slows down current development

• hard to understand
• have near to no test suite
• (or test suite is not helpful)

Historic velocity

What can we do about that?

We should not blame anyone

It is our responsibility to fix that

.. over time ..

.. one small step at a time ..

"Big Refactoring Project" is not a solution

• business needs new features yesterday
• you will rush to complete that "Big Project"
• and will make another mess

Problem A: Afraid to clean up

because it will break

Solution: Rely on the test suite

Problem B: There is no test suite

• or near to no test suite
• or it is not reliable

Solution: Create this test suite

But be LEAN about that

prioritize parts of legacy code (by frequency of change)

i.e.: when faced with new feature, that touches legacy code:

Make change easy

i.e.:

• increase test coverage for related functionality
• clean up relevant code

Then make an easy change

Be faster one small step at a time

While delivering increasing business value