dnf5: Run transaction test for offline transactions

A serialized offline transaction consists only of local packages
downloaded to the `<system state dir>/offline` location. Unfortunately,
PGP checks for these packages are disabled by default due to the
`localpkg_gpgcheck` option default value.
Instead of testing the serialized transaction, this patch performs an
RPM transaction test on the originally resolved transaction, which still
retains information about the repositories from which the packages were
downloaded.
This approach also saves time required for deserialization and resolving
the testing transaction.

dnf5/context.cpp

@@ -325,6 +325,27 @@ void Context::Impl::load_repos(bool load_system) {
 }
 
 void Context::Impl::store_offline(libdnf5::base::Transaction & transaction) {
+    // Test the transaction
+    base.get_config().get_tsflags_option().set(libdnf5::Option::Priority::RUNTIME, "test");
+    print_info(_("Testing offline transaction"));
+    auto result = transaction.run();
+    if (result != libdnf5::base::Transaction::TransactionRunResult::SUCCESS) {
+        print_error(libdnf5::utils::sformat(
+            _("Transaction failed: {}"), libdnf5::base::Transaction::transaction_result_to_string(result)));
+        for (auto const & entry : transaction.get_gpg_signature_problems()) {
+            print_error(entry);
+        }
+        for (auto & problem : transaction.get_transaction_problems()) {
+            print_error(libdnf5::utils::sformat(_("  - {}"), problem));
+        }
+        throw libdnf5::cli::SilentCommandExitError(1);
+    }
+
+    for (auto const & entry : transaction.get_gpg_signature_problems()) {
+        print_error(entry);
+    }
+
+    // Serialize the transaction
     const auto & installroot = base.get_config().get_installroot_option().get_value();
     const auto & offline_datadir = installroot / libdnf5::offline::DEFAULT_DATADIR.relative_path();
     std::filesystem::create_directories(offline_datadir);
@@ -349,41 +370,13 @@ void Context::Impl::store_offline(libdnf5::base::Transaction & transaction) {
     offline_data.set_status(libdnf5::offline::STATUS_DOWNLOAD_INCOMPLETE);
     state.write();
 
-    // First, serialize the transaction
     transaction.store_comps(comps_location);
 
     const auto transaction_json_path = offline_datadir / TRANSACTION_JSON;
     libdnf5::utils::fs::File transaction_json_file{transaction_json_path, "w"};
     transaction_json_file.write(transaction.serialize(packages_in_trans_dir, comps_in_trans_dir));
     transaction_json_file.close();
 
-    // Then, test the serialized transaction
-    const auto & goal = std::make_unique<libdnf5::Goal>(base);
-    goal->add_serialized_transaction(transaction_json_path);
-    auto test_transaction = goal->resolve();
-    if (test_transaction.get_problems() != libdnf5::GoalProblem::NO_PROBLEM) {
-        throw libdnf5::cli::GoalResolveError(transaction);
-    }
-    base.get_config().get_tsflags_option().set(libdnf5::Option::Priority::RUNTIME, "test");
-
-    print_info(_("Testing offline transaction"));
-    auto result = test_transaction.run();
-    if (result != libdnf5::base::Transaction::TransactionRunResult::SUCCESS) {
-        print_error(libdnf5::utils::sformat(
-            _("Transaction failed: {}"), libdnf5::base::Transaction::transaction_result_to_string(result)));
-        for (auto const & entry : transaction.get_gpg_signature_problems()) {
-            print_error(entry);
-        }
-        for (auto & problem : test_transaction.get_transaction_problems()) {
-            print_error(libdnf5::utils::sformat(_("  - {}"), problem));
-        }
-        throw libdnf5::cli::SilentCommandExitError(1);
-    }
-
-    for (auto const & entry : test_transaction.get_gpg_signature_problems()) {
-        print_error(entry);
-    }
-
     // Download and transaction test complete. Fill out entries in offline
     // transaction state file.
     offline_data.set_status(libdnf5::offline::STATUS_DOWNLOAD_COMPLETE);