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Test-Driven Development treats unit testing as an integral part of the design and implementation process. Often summarized as “test first, code after”, TDD is actually a recognition that in writing tests, we are
With our new knowledge of unit-testing frameworks, ideally, we have made it easier to write self-checking unit tests than to write the actual code to be tested.
The test-first philosophy is easiest to understand in a maintenance/debugging context.
Before attempting to debug, write a test that reproduces the failure.
How else will you know when you’ve fixed it?
From a practical point of view, debugging generally involves running the buggy input, over and over, while you add debugging output or step through with a debugger.
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Writing tests while “fresh” yields better tests than when they are done as an afterthought.
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Writing tests while “fresh” yields better tests than when they are done as an afterthought.
Thinking about boundary and special values tests helps clarify the software design
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Writing tests while “fresh” yields better tests than when they are done as an afterthought.
Thinking about boundary and special values tests helps clarify the software design
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Writing tests while “fresh” yields better tests than when they are done as an afterthought.
Thinking about boundary and special values tests helps clarify the software design
Encourages designing for testability
Every few years, software designers rediscover the principle of writing tests before implementing code.
Agile and TDD (Test-Driven Development) are just the latest in this long chain.
Writing tests while “fresh” yields better tests than when they are done as an afterthought.
Thinking about boundary and special values tests helps clarify the software design
Encourages designing for testability
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
It’s very common when writing tests to discover that the interface is incorrect or inadequate.
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
It’s very common when writing tests to discover that the interface is incorrect or inadequate.
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
It’s very common when writing tests to discover that the interface is incorrect or inadequate.
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
It’s very common when writing tests to discover that the interface is incorrect or inadequate.
“If it’s hard to write a test, it’s a signal that you have a design problem, not a testing problem. Loosely coupled, highly cohesive code is easy to test.” – Kent Beck
In writing a test, you are actually writing sample code of how the unit’s interface can be used.
Valuable as documentation
It’s very common when writing tests to discover that the interface is incorrect or inadequate.
The very act of trying to write black-box tests becomes itself an exercise in validation of the interface design!
Here you can see a plot of test cases on the vertical axis versus time (actually, commits to the version control system) on the horizontal axis during a project on which I practiced TFD.
Tests passed are shown in blue and failed tests are shown in red.
Notice the repeated pattern:
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