Add a custom no-op cargo test runner

.ci/cargo_glue.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+
+# This script is used by cargo to run the test runner with the 
+# specified arguments.
+#
+# We need this script because the cwd that cargo runs the runner in changes
+# depending on crate.
+
+cd "$GITHUB_WORKSPACE/.ci/"
+echo "In glue script with cwd: $(pwd)"
+echo "Got args: $@"

.ci/config.toml

@@ -0,0 +1,8 @@
+[target.x86_64-unknown-linux-gnu]
+# The command to execute instead of the compiled test binary. Cargo will append the
+# actual path to the compiled test executable and any arguments (like --list, --exact,
+# --nocapture) after this command. 
+# We use a tool without a slash in it so cargo will search $PATH.
+#
+# Before calling the `cargo test` we append the location of the glue to the path.
+runner = ["cargo_glue.sh"]

.github/workflows/ci_linux.yml

@@ -138,6 +138,13 @@ jobs:
           - name: RockyLinux-9 / CUDA-12.8.1
             image: "ghcr.io/rust-gpu/rust-cuda-rockylinux9-cuda12:latest"
     steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      # random command that forces rustup to install stuff in rust-toolchain
+      - name: Install rust-toolchain
+        run: cargo version
+
       - name: Download build artifacts
         uses: actions/download-artifact@v4
         with:
@@ -152,4 +159,5 @@ jobs:
           MODAL_TOKEN_ID: ${{ secrets.MODAL_TOKEN_ID }}
           MODAL_TOKEN_SECRET: ${{ secrets.MODAL_TOKEN_SECRET }}
         run: |
-          echo "Stubbed out"
+          export PATH="$PATH:$GITHUB_WORKSPACE/.ci"
+          cargo --config .ci/config.toml test --workspace --exclude "optix*" --exclude "path_tracer" --exclude "denoiser" --exclude "ex*" --exclude "cudnn*" --exclude "blastoff"

examples/cuda/cpu/add/build.rs

@@ -1,8 +1,10 @@
 use cuda_builder::CudaBuilder;
 
 fn main() {
-    CudaBuilder::new("../../gpu/add_gpu")
-        .copy_to("../../resources/add.ptx")
+    let manifest_dir = std::env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR exists");
+    let manifest_dir = std::path::Path::new(&manifest_dir);
+    CudaBuilder::new(manifest_dir.join("../../gpu/add_gpu"))
+        .copy_to(manifest_dir.join("../../resources/add.ptx"))
         .build()
         .unwrap();
 }