How strict should I be in the "do the simplest thing that could possible work" while doing TDD
- by Support - multilanguage SO
For TDD you have to
Create a test that fail
Do the simplest thing that could possible work to pass the test
Add more variants of the test and repeat
Refactor when a pattern emerge
With this approach you're supposing to cover all the cases ( that comes to my mind at least) but I'm wonder if am I being too strict here and if it is possible to "think ahead" some scenarios instead of simple discover them.
For instance, I'm processing a file and if it doesn't conform to a certain format I am to throw an InvalidFormatException
So my first test was:
@Test
void testFormat(){
// empty doesn't do anything...
processor.validate("empty.txt");
try {
processor.validate("invalid.txt");
assert false: "Should have thrown InvalidFormatException";
} catch( InvalidFormatException ife ) {
assert "Invalid format".equals( ife.getMessage() );
}
}
I run it and it fails because it doesn't throw an exception.
So the next thing that comes to my mind is: "Do the simplest thing that could possible work", so I :
public void validate( String fileName ) throws InvalidFormatException {
if(fileName.equals("invalid.txt") {
throw new InvalidFormatException("Invalid format");
}
}
Doh!! ( although the real code is a bit more complicated, I found my self doing something like this several times )
I know that I have to eventually add another file name and other test that would make this approach impractical and that would force me to refactor to something that makes sense ( which if I understood correctly is the point of TDD, to discover the patterns the usage unveils ) but:
Q: am I taking too literal the "Do the simplest thing..." stuff?
