From b432efec4ee8ea86fe1fabf0121a1a8613aec5b1 Mon Sep 17 00:00:00 2001
From: ascandone <alescandone@gmail.com>
Date: Tue, 4 Aug 2026 15:42:14 +0200
Subject: [PATCH] fix(cmd): propagate specs file write errors in test-init

runTestInitCmd discarded os.WriteFile's error, so a failed write (disk
full, permission denied, target path already a directory, ...) was
reported as success: "Created specs file" printed and exit 0, with
nothing actually written.

Left the json.MarshalIndent error un-propagated: Specs's fields are all
strings/bools/*big.Int, none of which json.Marshal can fail on, so
there's no reachable input that exercises that branch.
---
 internal/cmd/test_init.go               |  4 +++-
 internal/cmd/test_init_internal_test.go | 30 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 internal/cmd/test_init_internal_test.go

diff --git a/internal/cmd/test_init.go b/internal/cmd/test_init.go
index f66cc806..e13b8d70 100644
--- a/internal/cmd/test_init.go
+++ b/internal/cmd/test_init.go
@@ -192,7 +192,9 @@ func runTestInitCmd(opts testInitArgs) error {
 
 	marshaled, _ := json.MarshalIndent(specs, "", "  ")
 
-	_ = os.WriteFile(opts.path+".specs.json", marshaled, 0644)
+	if err := os.WriteFile(opts.path+".specs.json", marshaled, 0644); err != nil {
+		return fmt.Errorf("failed to write specs file: %w", err)
+	}
 
 	fmt.Printf("✅ Created specs file: %s.specs.json\n", opts.path)
 
diff --git a/internal/cmd/test_init_internal_test.go b/internal/cmd/test_init_internal_test.go
new file mode 100644
index 00000000..34596ec8
--- /dev/null
+++ b/internal/cmd/test_init_internal_test.go
@@ -0,0 +1,30 @@
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const testInitNumscript = `send [USD/2 100] (
+	source = @world
+	destination = @bob
+)
+`
+
+func TestRunTestInitCmdPropagatesWriteError(t *testing.T) {
+	dir := t.TempDir()
+	scriptPath := filepath.Join(dir, "main.num")
+	require.NoError(t, os.WriteFile(scriptPath, []byte(testInitNumscript), 0644))
+
+	// create a directory where the specs file should be written, so that
+	// os.WriteFile fails deterministically
+	require.NoError(t, os.Mkdir(scriptPath+".specs.json", 0755))
+
+	err := runTestInitCmd(testInitArgs{path: scriptPath})
+
+	require.Error(t, err)
+	require.ErrorContains(t, err, "failed to write specs file")
+}