Fixes #54 ### Why tl;dr: Each rust file in `tests/` becomes an integration test entry point. Because we import `harness` from `mod.rs` we run the tests twice. This new structure means we only enter via `mod.rs` and run tests once. See [Submodules in Integration Tests](https://doc.rust-lang.org/book/ch11-03-test-organization.html#submodules-in-integration-tests). ### Test I tested by running a single duplicated test with `cargo nextest run unzip_low_u32x4_neon --workspace --locked --all-features --no-fail-fast --target aarch64-apple-darwin` Before: ```sh ──────────── Nextest run ID af179010-cb8a-4c82-bead-7d35b42513c0 with nextest profile: default Starting 2 tests across 5 binaries (449 tests skipped) PASS [ 0.007s] fearless_simd_tests::harness unzip_low_u32x4_neon PASS [ 0.007s] fearless_simd_tests::tests harness::unzip_low_u32x4_neon ──────────── Summary [ 0.011s] 2 tests run: 2 passed, 449 skipped ``` After: ```sh ──────────── Nextest run ID d7c6944c-8458-4dd6-abef-fcfa98ee016b with nextest profile: default Starting 1 test across 4 binaries (226 tests skipped) PASS [ 0.012s] fearless_simd_tests::tests harness::unzip_low_u32x4_neon ──────────── Summary [ 0.017s] 1 test run: 1 passed, 226 skipped ```