test(nodes): use Ginkgo for hash sidecar tests

Convert the hash sidecar tests to the required Ginkgo and Gomega style.
This resolves the forbidigo CI failures and preserves all four cases.

Assisted-by: Codex:gpt-6 golangci-lint

core/services/nodes/hash_sidecar_test.go

@@ -5,26 +5,22 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
 )
 
-func TestHashSidecarCannotEscapeFileDirectory(t *testing.T) {
-	for _, mode := range []string{"server", "stager"} {
-		t.Run(mode, func(t *testing.T) {
-			dir := t.TempDir()
+var _ = Describe("Hash sidecar containment", func() {
+	DescribeTable("does not trust or overwrite a sidecar outside the model directory",
+		func(mode string) {
+			dir := GinkgoT().TempDir()
 			path := filepath.Join(dir, "model.bin")
-			outside := filepath.Join(t.TempDir(), "outside")
+			outside := filepath.Join(GinkgoT().TempDir(), "outside")
 			content := []byte("model contents")
 			forged := strings.Repeat("a", 64)
-			if err := os.WriteFile(path, content, 0600); err != nil {
-				t.Fatal(err)
-			}
-			if err := os.WriteFile(outside, []byte(forged), 0600); err != nil {
-				t.Fatal(err)
-			}
-			if err := os.Symlink(outside, path+hashSidecarSuffix); err != nil {
-				t.Fatal(err)
-			}
+			Expect(os.WriteFile(path, content, 0600)).To(Succeed())
+			Expect(os.WriteFile(outside, []byte(forged), 0600)).To(Succeed())
+			Expect(os.Symlink(outside, path+hashSidecarSuffix)).To(Succeed())
 			var got string
 			var err error
 			if mode == "server" {
@@ -32,59 +28,42 @@ func TestHashSidecarCannotEscapeFileDirectory(t *testing.T) {
 			} else {
 				got, err = hashLocalCached(context.Background(), path)
 			}
-			if err != nil {
-				t.Fatal(err)
-			}
-			if got == forged {
-				t.Fatal("trusted hash from sidecar outside the model directory")
-			}
+			Expect(err).NotTo(HaveOccurred())
+			Expect(got).NotTo(Equal(forged), "trusted hash from sidecar outside the model directory")
 			after, err := os.ReadFile(outside)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if string(after) != forged {
-				t.Fatal("overwrote file outside the model directory")
-			}
-		})
-	}
-}
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(after)).To(Equal(forged), "overwrote file outside the model directory")
+		},
+		Entry("server", "server"),
+		Entry("stager", "stager"),
+	)
 
-func TestHashSidecarWriteDoesNotFollowSymlinks(t *testing.T) {
-	for _, external := range []bool{false, true} {
-		dir := t.TempDir()
-		targetDir := dir
-		if external {
-			targetDir = t.TempDir()
-		}
-		target := filepath.Join(targetDir, "original")
-		path := filepath.Join(dir, "model.bin.sha256")
-		if err := os.WriteFile(target, []byte("do not overwrite"), 0600); err != nil {
-			t.Fatal(err)
-		}
-		if err := os.Symlink(target, path); err != nil {
-			t.Fatal(err)
-		}
-		if _, err := readHashSidecar(path); err == nil {
-			t.Fatal("read symlinked sidecar")
-		}
-		hash := strings.Repeat("b", 64)
-		if err := writeHashSidecar(path, hash); err != nil {
-			t.Fatal(err)
-		}
-		data, err := os.ReadFile(target)
-		if err != nil || string(data) != "do not overwrite" {
-			t.Fatalf("target changed: %q, %v", data, err)
-		}
-		data, err = readHashSidecar(path)
-		if err != nil || string(data) != hash {
-			t.Fatalf("incorrect sidecar: %q, %v", data, err)
-		}
-		info, err := os.Stat(path)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if info.Mode().Perm() != 0600 {
-			t.Fatalf("sidecar permissions: %v", info.Mode())
-		}
-	}
-}
+	DescribeTable("replaces a sidecar symlink without changing its target",
+		func(external bool) {
+			dir := GinkgoT().TempDir()
+			targetDir := dir
+			if external {
+				targetDir = GinkgoT().TempDir()
+			}
+			target := filepath.Join(targetDir, "original")
+			path := filepath.Join(dir, "model.bin.sha256")
+			Expect(os.WriteFile(target, []byte("do not overwrite"), 0600)).To(Succeed())
+			Expect(os.Symlink(target, path)).To(Succeed())
+			_, err := readHashSidecar(path)
+			Expect(err).To(HaveOccurred(), "read symlinked sidecar")
+			hash := strings.Repeat("b", 64)
+			Expect(writeHashSidecar(path, hash)).To(Succeed())
+			data, err := os.ReadFile(target)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(data)).To(Equal("do not overwrite"), "target changed")
+			data, err = readHashSidecar(path)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(string(data)).To(Equal(hash))
+			info, err := os.Stat(path)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(info.Mode().Perm()).To(Equal(os.FileMode(0600)))
+		},
+		Entry("target inside the model directory", false),
+		Entry("target outside the model directory", true),
+	)
+})