One liner JUnit Productivity Tip

There's nothing clever or complicated about this tip - nevertheless it's one that once discovered saved me a lot of time.

The tip is for the case when you're comparing two long strings.

Say you have the following code which compares two strings:

String expect = "a,aah,aahed,aahing,aahs,aardvark,aardvarks,aardwolf,ab,abaci,aback,abacus,abacuses,abaft,abalone,abalones,abandon,abandoned,abandonedly,abandonee,abandoner,abandoners,abandoning,abandonment,abandonments,abandons,abase,abased,abasedly,abasement,abaser,abasers,abases,abash,abashed,abashedly,abashes,abashing,abashment,abashments,abasing,abatable,abate,abated,abatement,abatements,abater,abaters,abates,abating,abatis,abatises,abator,abattoir,abattoirs,abbacies,abbacy,abbatial,abbe,abbes,abbess,abbesses";

String actual = "a,aah,aahed,aahing,aahs,aardvark,aardvarks,aardwolf,ab,abaci,aback,abacus,abacuses,abaft,abalone,abalones,abandon,abandoned,abandonedly,abandonee,abandoner,abandoners,abandoning,abandonment,abandonments,abandons,abase,abased,abasedly,abasement,abaser,abasers,abases,abash,abashed,abashedly,abashes,abashing,abashment,abashments,abasing,abatable,abate,abated,abatement,abatements,abater,abaters,abates,abating,abatis,abatises,abator,abattoir,abattoirs,abbacies,abbacy ,abbatial,abbe,abbes,abbess,abbesses";

assertEquals(expect, actual);

As it happens these strings are not exactly the same so you get this failure message when you run the test in IntelliJ:

org.junit.ComparisonFailure: 
Expected :a,aah,aahed,aahing,aahs,aardvark,aardvarks,aardwolf,ab,abaci,aback,abacus,abacuses,abaft,abalone,abalones,abandon,abandoned,abandonedly,abandonee,abandoner,abandoners,abandoning,abandonment,abandonments,abandons,abase,abased,abasedly,abasement,abaser,abasers,abases,abash,abashed,abashedly,abashes,abashing,abashment,abashments,abasing,abatable,abate,abated,abatement,abatements,abater,abaters,abates,abating,abatis,abatises,abator,abattoir,abattoirs,abbacies,abbacy,abbatial,abbe,abbes,abbess,abbesses
Actual   :a,aah,aahed,aahing,aahs,aardvark,aardvarks,aardwolf,ab,abaci,aback,abacus,abacuses,abaft,abalone,abalones,abandon,abandoned,abandonedly,abandonee,abandoner,abandoners,abandoning,abandonment,abandonments,abandons,abase,abased,abasedly,abasement,abaser,abasers,abases,abash,abashed,abashedly,abashes,abashing,abashment,abashments,abasing,abatable,abate,abated,abatement,abatements,abater,abaters,abates,abating,abatis,abatises,abator,abattoir,abattoirs,abbacies,abbacy ,abbatial,abbe,abbes,abbess,abbesses

 

The error messages isn't particularly helpful to say the least....

Fortunately IntelliJ provides us with a 'click to see the difference dialog' - but when you click and open the dialog, although it will highlight the difference it's really not immediately obvious where the differences are and you end up scrolling a very long way to find them. And it's certainly impossible to see all the differences at a glance.



So here's the tip instead of this:

assertEquals(expect, actual);

Insert new lines into your string as below:

assertEquals(expect.replace(',', '\n'), actual.replace(',', '\n'));

Then when you click to see the difference you get a dialog that looks like this and you 

are able to see the issues at a glance. Simple but effective.