add error contexts to Go::compile

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

Author: dicej

crates/test/src/go.rs

@@ -1,5 +1,5 @@
 use crate::{Compile, LanguageMethods, Runner, Verify};
-use anyhow::Result;
+use anyhow::{Context as _, Result};
 use std::env;
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -63,14 +63,15 @@ impl LanguageMethods for Go {
         // convention.  For example, if the filename is `test.go`, then we'll
         // also include `${prefix}+test.go` for any value of `${prefix}`.
         for path in all_paths(&compile.component.path)? {
-            let test = fs::read_to_string(&path)?;
+            let test = fs::read_to_string(&path)
+                .with_context(|| format!("unable to read `{}`", path.display()))?;
             let package_name = package_name(&test);
             let package_dir = compile.bindings_dir.join(package_name);
-            fs::create_dir_all(&package_dir)?;
-            fs::write(
-                &package_dir.join(path.file_name().unwrap()),
-                test.as_bytes(),
-            )?;
+            fs::create_dir_all(&package_dir)
+                .with_context(|| format!("unable to create `{}`", package_dir.display()))?;
+            let output = &package_dir.join(path.file_name().unwrap());
+            fs::write(output, test.as_bytes())
+                .with_context(|| format!("unable to write `{}`", output.display()))?;
         }
 
         runner.run_command(
@@ -124,7 +125,11 @@ fn all_paths(path: &Path) -> Result<Vec<PathBuf>> {
         .and_then(|name| name.strip_suffix(suffix))
     {
         let suffix = &format!("+{name}{suffix}");
-        for entry in path.parent().unwrap().read_dir()? {
+        let parent = path.parent().unwrap();
+        for entry in parent
+            .read_dir()
+            .with_context(|| format!("unable to read dir `{}`", parent.display()))?
+        {
             let entry = entry?;
             if entry
                 .file_name()