How to show diff of failures?

[gaborbernat]

I am using junit 5 with assertj, but when a failure happens (for a 100 line string comparision) all I get is:

 org.opentest4j.AssertionFailedError:
    expected:
....

	but was:
....

        at app//main.BaseTester.assertPatchedCallstackOnDisk(BaseTester.groovy)

Is there a way to get something like git diff does?

[joel-costigliola]

Not really something AssertJ can control since what you get comes from opentest4j and the capabilities of your IDE.

The IDE could inspect the AssertionFailedError, which has the actual and expected values and if these are strings show a better diff

[gaborbernat]

What about in the CI outside of the IDE (using gradle..)?

[joel-costigliola]

I don't think they could do much.

Having said that, we could add an option to generate an error message with diff style syntax when actual and expected are strings but that would not be the default IMO.

[joel-costigliola]

Usually IDEs have visual diff showing actual and expected string representation in a diff editor

[gaborbernat]

Is there a Gradle plugin to take the AssertionFailedError and calc the diff? A flag would be also nice.

[joel-costigliola]

I'm not aware of any