test: enable Subsonic response snapshot tests on Windows (#5427)

* fix(test): enable Subsonic response snapshot tests on Windows

Replaced cupaloy with a simple custom snapshot matcher that normalizes
CRLF line endings before comparison. The tests were skipped on Windows
via a //go:build unix tag because Git for Windows checks out snapshot
files with CRLF, while Go's xml/json.MarshalIndent always produces LF,
causing direct string comparison to fail. The new matcher reads snapshot
files with os.ReadFile and normalizes \r\n to \n before comparing.
Also added a .gitattributes in the .snapshots directory to enforce LF
checkout, and removed the now-unused cupaloy dependency.

* fix(test): add UPDATE_SNAPSHOTS support to custom snapshot matcher

Restore the ability to update snapshots via `make snapshots`
(UPDATE_SNAPSHOTS=true), which was lost when replacing cupaloy
with the custom matcher.

server/subsonic/responses/.snapshots/.gitattributes

@@ -0,0 +1 @@
+* eol=lf

server/subsonic/responses/responses_suite_test.go

@@ -1,14 +1,17 @@
 package responses
 
 import (
+	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
-	"github.com/bradleyjkemp/cupaloy/v2"
 	"github.com/navidrome/navidrome/log"
 	"github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
 	"github.com/onsi/gomega/types"
+	"github.com/pmezard/go-difflib/difflib"
 )
 
 func TestSubsonicApiResponses(t *testing.T) {
@@ -18,25 +21,61 @@ func TestSubsonicApiResponses(t *testing.T) {
 }
 
 func MatchSnapshot() types.GomegaMatcher {
-	c := cupaloy.New(cupaloy.FailOnUpdate(false))
-	return &snapshotMatcher{c}
+	return &snapshotMatcher{}
 }
 
 type snapshotMatcher struct {
-	c *cupaloy.Config
+	diff string
 }
 
-func (matcher snapshotMatcher) Match(actual any) (success bool, err error) {
-	actualJson := strings.TrimSpace(string(actual.([]byte)))
-	err = matcher.c.SnapshotWithName(ginkgo.CurrentSpecReport().FullText(), actualJson)
-	success = err == nil
-	return
+func (matcher *snapshotMatcher) Match(actual any) (success bool, err error) {
+	actualBytes, ok := actual.([]byte)
+	if !ok {
+		return false, fmt.Errorf("MatchSnapshot expects []byte, got %T", actual)
+	}
+
+	name := ginkgo.CurrentSpecReport().FullText()
+	actualStr := strings.TrimSpace(string(actualBytes))
+
+	snapshotPath := filepath.Join(".snapshots", name)
+
+	// Support UPDATE_SNAPSHOTS=true for `make snapshots`
+	if _, update := os.LookupEnv("UPDATE_SNAPSHOTS"); update {
+		err := os.MkdirAll(".snapshots", os.ModePerm)
+		if err != nil {
+			return false, err
+		}
+		return true, os.WriteFile(snapshotPath, []byte(actualStr+"\n"), 0600)
+	}
+
+	expected, err := os.ReadFile(snapshotPath)
+	if err != nil {
+		return false, err
+	}
+
+	// Normalize line endings so snapshots work on Windows (CRLF) and Unix (LF)
+	normalizedExpected := strings.ReplaceAll(string(expected), "\r\n", "\n")
+	normalizedExpected = strings.TrimSpace(normalizedExpected)
+
+	if actualStr == normalizedExpected {
+		return true, nil
+	}
+
+	diff, _ := difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
+		A:        difflib.SplitLines(normalizedExpected),
+		B:        difflib.SplitLines(actualStr),
+		FromFile: "snapshot",
+		ToFile:   "actual",
+		Context:  3,
+	})
+	matcher.diff = diff
+	return false, nil
 }
 
-func (matcher snapshotMatcher) FailureMessage(_ any) (message string) {
-	return "Expected to match saved snapshot\n"
+func (matcher *snapshotMatcher) FailureMessage(_ any) (message string) {
+	return "Expected to match saved snapshot\n" + matcher.diff
 }
 
-func (matcher snapshotMatcher) NegatedFailureMessage(_ any) (message string) {
+func (matcher *snapshotMatcher) NegatedFailureMessage(_ any) (message string) {
 	return "Expected to not match saved snapshot\n"
 }

server/subsonic/responses/responses_test.go

@@ -1,8 +1,3 @@
-//go:build unix
-
-// TODO Fix snapshot tests in Windows
-// Response Snapshot tests. Only run in Linux and macOS, as they fail in Windows
-// Probably because of EOL char differences
 package responses_test
 
 import (