Formatting output so that Intellij Idea shows diffs for two texts

Question

I would like to be able to print in the logs a message for which intellij idea would present a nice way of comparing two objects (strings). This happens automatically for the er

Answer 1

IntelliJ IDEA is using the hardcoded regular expression. If the text matches the pattern, it will suggest to click to view the difference.

The pattern is:

expected:<bla-blah> but was:<blah-blah-blah>

Output should match the format of assertEquals or assertThat.

The exact patterns are somewhat scattered around the code in IDEA, but some are e.g. here.

Answer 2

I had the same Problem and found the solution in https://github.com/joel-costigliola/assertj-core/issues/1364#issuecomment-440800958

You should throw an org.junit.ComparisonFailure. Then IntelliJ will display the <Click to see difference>