Consider using assertThatExceptionOfType rather than assertThatThrownBy

[philwebb]

Recently Spring Integration migrated to AssertJ and started using assertThatThrownBy() instead of an ExpectedException @Rule.

Spring Boot also made the same migration but we opted to use assertThatExceptionOfType rather than assertThatThrownBy because we felt it was a little easier to use and because it has specialized versions for IllegalArguementException, IOException and IllegalStateException.

For example, the following:

assertThatThrownBy(() -> listener.onMessage(mock(Message.class)))
				.isInstanceOf(MessageConversionException.class)
				.hasCauseInstanceOf(IllegalStateException.class);

would be:

assertThatExceptionOfType(MessageConversionException.class).isThrownBy(()->
				listener.onMessage(mock(Message.class)))
				.withCauseInstanceOf(IllegalStateException.class);

We also have a checkstyle rule to enforce the use of assertThatIllegalArgumentExceptionIsThrownBy() etc.

I thought it was worth raising an issue in case you also wanted to consider it.

[artembilan]

Nice! Thank you @philwebb !

Will consider to do that soon. 😄