Add Spotify mock server and integration tests

pkg/testutils/spotify/handlers.go

@@ -0,0 +1,96 @@
+// Package spotify provides shared handlers for mocking the Spotify API.
+package spotify
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+)
+
+// NewSpotifyHandler returns a new http.Handler configured with Spotify mock endpoints.
+func NewSpotifyHandler() http.Handler {
+	mux := http.NewServeMux()
+
+	// OAuth Token Endpoint
+	mux.HandleFunc("/api/token", HandleToken)
+
+	// User Profile Endpoint
+	mux.HandleFunc("/v1/me", HandleMe)
+	mux.HandleFunc("/me", HandleMe)
+
+	return mux
+}
+
+// HandleToken simulates the Spotify OAuth token endpoint.
+func HandleToken(w http.ResponseWriter, r *http.Request) {
+	log.Printf("[Spotify Mock] Token request: %s", r.Method)
+
+	if r.Method != http.MethodPost {
+		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "Bad request", http.StatusBadRequest)
+		return
+	}
+
+	grantType := r.FormValue("grant_type")
+	log.Printf("[Spotify Mock] Grant type: %s", grantType)
+
+	resp := map[string]interface{}{
+		"access_token":  "mock-access-token",
+		"token_type":    "Bearer",
+		"expires_in":    3600,
+		"refresh_token": "mock-refresh-token",
+		"scope":         "user-read-private user-read-email",
+	}
+
+	switch grantType {
+	case "authorization_code":
+		code := r.FormValue("code")
+		if code == "" {
+			http.Error(w, `{"error":"invalid_grant"}`, http.StatusBadRequest)
+			return
+		}
+	case "refresh_token":
+		refreshToken := r.FormValue("refresh_token")
+		if refreshToken == "" {
+			http.Error(w, `{"error":"invalid_grant"}`, http.StatusBadRequest)
+			return
+		}
+	default:
+		http.Error(w, `{"error":"unsupported_grant_type"}`, http.StatusBadRequest)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		log.Printf("Error encoding token response: %v", err)
+	}
+}
+
+// HandleMe simulates the Spotify user profile endpoint.
+func HandleMe(w http.ResponseWriter, r *http.Request) {
+	log.Printf("[Spotify Mock] Profile request: %s", r.Method)
+
+	auth := r.Header.Get("Authorization")
+	if auth != "Bearer mock-access-token" {
+		http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
+		return
+	}
+
+	resp := map[string]interface{}{
+		"id":           "mock-user-id",
+		"display_name": "Mock User",
+		"email":        "mock@example.com",
+		"uri":          "spotify:user:mock-user-id",
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		log.Printf("Error encoding profile response: %v", err)
+	}
+}