Remove outdated docs

Author: LegNeato

docs/src/testing.md

@@ -54,57 +54,5 @@ cargo compiletest --target-env=vulkan1.1
 cargo compiletest --target-env=vulkan1.1,spv.1.3
 ```
 
-## Diff Tests
-
-### Adding Tests
-
-To add a test, you need to write your GPU code twice--once in Rust, and once in WGSL.
-Together these two shaders/kernels form a logical test. The testing harness will run
-both programs, compare their output, and fail the test if they don't match. The location
-of the test in the "pipelines/" directory determines the output type.
-
-Tests can control the behavior of the test harness via comment directives in the
-corresponding Rust code. Comment directives are not supported in WGSL.
-
-### Fragment and Vertex Shaders
-
-Tests in "pipelines/graphics/" are used for vertex and fragment shaders. The test
-harness will save the resulting display buffers to images and compare them, failing if
-they do not match. If they do not match, their paths will be output so that you can
-determine what is different.
-
-You must currently name your fragment entrypoint `main_fs` and your vertex entry point
-`main_vs`.
-
-### Compute Kernels / Shaders
-
-Tests in "pipelines/compute/" are used for compute shaders. The test harness will
-compare the two binary outputs and fail the test if they don't match.
-
-The output type is specified by a comment directive:
-
-```
-// output: [u8]
-```
-
-Valid values are `[u8]`, `f32`, and `u32`.
-
-You must currently name your compute entrypoint `main_cs`.
-
-### Fragment and Vertex with Compute Shaders
-
-Tests in "pipelines/mixed/" are used for running vertex, fragment, and compute shaders
-at the same time. As with vertex and fragment shaders, test harness will save the
-resulting display buffers to images and compare them.
-
-### Filtering Tests
-
-Similar to compiletests, `cargo difftest` supports running specific tests by passing
-substrings of their paths:
-
-```bash
-cargo difftest compute simple
-```
-
 [`compiletest`]: https://github.com/laumann/compiletest-rs
 [rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org/tests/intro.html