Set the path to the wasi adapter properly. (#772)

Preivously the adapter as assumed to be at set relative path to the
target directory which was not true when CARGO_TARGET_DIR was set. Now,
the adapter is assumed to be at a set relative path to the artifacts crate which
should always be the case.

Signed-off-by: Ryan Levick <ryan.levick@fermyon.com>

crates/test-rust-wasm/artifacts/build.rs

@@ -6,8 +6,9 @@ fn main() {
     std::env::remove_var("CARGO_ENCODED_RUSTFLAGS");
 
     let out_dir = PathBuf::from(std::env::var_os("OUT_DIR").unwrap());
+    let manifest_dir = PathBuf::from(std::env::var_os("CARGO_MANIFEST_DIR").unwrap());
 
-    let wasi_adapter = out_dir.join("../../../../../tests/wasi_snapshot_preview1.reactor.wasm");
+    let wasi_adapter = manifest_dir.join("../../../tests/wasi_snapshot_preview1.reactor.wasm");
 
     let mut cmd = Command::new("cargo");
     cmd.arg("build")

tests/runtime/main.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use heck::ToUpperCamelCase;
 
 use std::borrow::Cow;
@@ -147,7 +147,8 @@ fn tests(name: &str, dir_name: &str) -> Result<Vec<PathBuf>> {
     out_dir.push("runtime-tests");
     out_dir.push(name);
 
-    let wasi_adapter = std::fs::read(&test_artifacts::ADAPTER)?;
+    let wasi_adapter =
+        std::fs::read(&test_artifacts::ADAPTER).context("failed to read the wasi adapter")?;
 
     drop(std::fs::remove_dir_all(&out_dir));
     std::fs::create_dir_all(&out_dir)?;