Currently you have to use -vv to show the whole diff for dicts, and not to truncate in general.

Code:

• pytest/src/_pytest/assertion/util.py

  Lines 295 to 296 in c00d934

  	if same and verbose < 2:
  	explanation += [u("Omitting %s identical items, use -vv to show") % len(same)]

• pytest/src/_pytest/assertion/truncate.py

  Lines 27 to 32 in c00d934

  	def _should_truncate_item(item):
  	"""
  	Whether or not this test item is eligible for truncation.
  	"""
  	verbose = item.config.option.verbose
  	return verbose < 2 and not _running_on_ci()

1. there should be a distinct option additionally, because I usually have to re-run the test with -vv then, but would rather have it by default - without using very verbose mode by default

2. pytest.assertion.truncate checks if it is running on CI and enables this then always. This should also be done for comparing dicts anyway. Should I file a separate issue / create a PR for this already?

I would like to add this to the config file for projects where it makes sense, e.g. https://github.com/Vimjas/covimerage, where most of the tests are comparing program output (by lines), which usually gets truncated.
-vv would still have the same effect of course.