New ServiceExceptionAssert.hasArgSatisfying(...) assertion

What happened?

I have an arg that's a long, dynamically computed string (a stacktrace). I'd like to confirm that it contains a certain substring, with a syntax like:

assertThatServiceExceptionThrownBy(() -> throwIt())
  .hasType(MyErrors.MY_ERROR)
  .hasArgSatisfying(arg -> {
    assertThat(arg.getName()).isEqualTo("my-arg");
    assertThat(arg.getValue()).asString().contains("my-substring");
  });

or maybe like this:

assertThatServiceExceptionThrownBy(() -> throwIt())
  .hasType(MyErrors.MY_ERROR)
  .hasArgWithNameSatisfying("my-arg", value -> assertThat(value).asString().contains("my-substring"));

Workaround

Right now I'm doing something like this, but would love to improve it:

assertThatServiceExceptionThrownBy(() -> throwIt())
  .hasType(MyErrors.MY_ERROR)
  .satisfies(serviceException -> assertThat(serviceException.getArgs())
    .satisfiesOnlyOnce(arg -> {
      assertThat(arg.getName()).isEqualTo("my-arg");
      assertThat(arg.getValue()).asString().contains("my-substring");
    });
  });

Start by locating ServiceExceptionAssert and its existing argument assertion methods. Review how those assertions are tested, then add a callback-based argument assertion matching the requested usage and cover successful matching and failure cases in the relevant tests.