Non Utf8 files causes

[amiller68]

Running assert_paths!() on directories containing non utf8 data causes critical errors:

thread 'test::test_pipeline' panicked at 'called `Result::unwrap()` on an `Err` value: [Critical("failed reading line from \"test/unpacked/w2_d2_s1024_balanced/0/0\", reason: stream did not contain valid UTF-8"), Critical("failed reading line from \"test/unpacked/w2_d2_s1024_balanced/0/1\", reason: stream did not contain valid UTF-8"), Critical("failed reading line from \"test/unpacked/w2_d2_s1024_balanced/1/0\", reason: stream did not contain valid UTF-8"), Critical("failed reading line from \"test/unpacked/w2_d2_s1024_balanced/1/1\", reason: stream did not contain valid UTF-8")]'