test: add tests for userName and AbsolutePath in core/common.go

Added Ginkgo/Gomega tests for userName and AbsolutePath functions in core/common.go. Tests cover normal and error cases, using existing mocks and helpers. This improves coverage and ensures correct behavior for user context extraction and library path resolution.

core/common_test.go

@@ -0,0 +1,55 @@
+package core
+
+import (
+	"context"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/model/request"
+	"github.com/navidrome/navidrome/tests"
+)
+
+var _ = Describe("common.go", func() {
+	Describe("userName", func() {
+		It("returns the username from context", func() {
+			ctx := request.WithUser(context.Background(), model.User{UserName: "testuser"})
+			Expect(userName(ctx)).To(Equal("testuser"))
+		})
+
+		It("returns 'UNKNOWN' if no user in context", func() {
+			ctx := context.Background()
+			Expect(userName(ctx)).To(Equal("UNKNOWN"))
+		})
+	})
+
+	Describe("AbsolutePath", func() {
+		var (
+			ds    *tests.MockDataStore
+			libId int
+			path  string
+		)
+
+		BeforeEach(func() {
+			ds = &tests.MockDataStore{}
+			libId = 1
+			path = "music/file.mp3"
+			mockLib := &tests.MockLibraryRepo{}
+			mockLib.SetData(model.Libraries{{ID: libId, Path: "/library/root"}})
+			ds.MockedLibrary = mockLib
+		})
+
+		It("returns the absolute path when library exists", func() {
+			ctx := context.Background()
+			abs := AbsolutePath(ctx, ds, libId, path)
+			Expect(abs).To(Equal("/library/root/music/file.mp3"))
+		})
+
+		It("returns the original path if library not found", func() {
+			ctx := context.Background()
+			abs := AbsolutePath(ctx, ds, 999, path)
+			Expect(abs).To(Equal(path))
+		})
+	})
+})