Add tests for main package, manager, and various components

- Introduced unit tests for the main package to ensure compilation.
- Added tests for the manager, including validation of upload sessions and handling of Blender binary paths.
- Implemented tests for job token generation and validation, ensuring security and integrity.
- Created tests for configuration management and database schema to verify functionality.
- Added tests for logger and runner components to enhance overall test coverage and reliability.

internal/manager/manager_test.go

@@ -0,0 +1,50 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestCheckWebSocketOrigin_DevelopmentAllowsOrigin(t *testing.T) {
+	t.Setenv("PRODUCTION", "false")
+	req := httptest.NewRequest("GET", "http://localhost/ws", nil)
+	req.Host = "localhost:8080"
+	req.Header.Set("Origin", "http://example.com")
+	if !checkWebSocketOrigin(req) {
+		t.Fatal("expected development mode to allow origin")
+	}
+}
+
+func TestCheckWebSocketOrigin_ProductionSameHostAllowed(t *testing.T) {
+	t.Setenv("PRODUCTION", "true")
+	t.Setenv("ALLOWED_ORIGINS", "")
+	req := httptest.NewRequest("GET", "http://localhost/ws", nil)
+	req.Host = "localhost:8080"
+	req.Header.Set("Origin", "http://localhost:8080")
+	if !checkWebSocketOrigin(req) {
+		t.Fatal("expected same-host origin to be allowed")
+	}
+}
+
+func TestRespondErrorWithCode_IncludesCodeField(t *testing.T) {
+	s := &Manager{}
+	rr := httptest.NewRecorder()
+	s.respondErrorWithCode(rr, http.StatusBadRequest, "UPLOAD_SESSION_EXPIRED", "Upload session expired.")
+
+	if rr.Code != http.StatusBadRequest {
+		t.Fatalf("status = %d, want %d", rr.Code, http.StatusBadRequest)
+	}
+	var payload map[string]string
+	if err := json.Unmarshal(rr.Body.Bytes(), &payload); err != nil {
+		t.Fatalf("failed to decode response: %v", err)
+	}
+	if payload["code"] != "UPLOAD_SESSION_EXPIRED" {
+		t.Fatalf("unexpected code: %q", payload["code"])
+	}
+	if payload["error"] == "" {
+		t.Fatal("expected non-empty error message")
+	}
+}
+