First Commit

ext/libpqxx-7.7.3/test/test29.cxx

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+#include <cstdio>
+#include <iostream>
+#include <vector>
+
+#include <pqxx/nontransaction>
+#include <pqxx/transaction>
+
+#include "test_helpers.hxx"
+
+using namespace pqxx;
+
+
+// Test program for libpqxx.  Open connection to database, start a transaction,
+// abort it, and verify that it "never happened."
+//
+// The program will attempt to add an entry to a table called "pqxxevents",
+// with a key column called "year"--and then abort the change.
+namespace
+{
+// Let's take a boring year that is not going to be in the "pqxxevents" table
+constexpr int BoringYear{1977};
+
+std::string const Table{"pqxxevents"};
+
+
+// Count events, and boring events, in table
+std::pair<int, int> CountEvents(transaction_base &tx)
+{
+  std::string const events_query{"SELECT count(*) FROM " + Table};
+  std::string const boring_query{
+    events_query + " WHERE year=" + to_string(BoringYear)};
+
+  return std::make_pair(
+    tx.query_value<int>(events_query), tx.query_value<int>(boring_query));
+}
+
+
+// Try adding a record, then aborting it, and check whether the abort was
+// performed correctly.
+void Test(connection &conn, bool ExplicitAbort)
+{
+  std::vector<std::string> BoringRow{to_string(BoringYear), "yawn"};
+
+  std::pair<int, int> EventCounts;
+
+  // First run our doomed transaction.  This will refuse to run if an event
+  // exists for our Boring Year.
+  {
+    // Begin a transaction acting on our current connection; we'll abort it
+    // later though.
+    work Doomed(conn, "Doomed");
+
+    // Verify that our Boring Year was not yet in the events table
+    EventCounts = CountEvents(Doomed);
+
+    PQXX_CHECK_EQUAL(
+      EventCounts.second, 0,
+      "Can't run; " + to_string(BoringYear) + " is already in the table.");
+
+    // Now let's try to introduce a row for our Boring Year
+    Doomed.exec0(
+      "INSERT INTO " + Table +
+      "(year, event) "
+      "VALUES (" +
+      to_string(BoringYear) + ", 'yawn')");
+
+    auto Recount{CountEvents(Doomed)};
+    PQXX_CHECK_EQUAL(Recount.second, 1, "Unexpected number of events.");
+    PQXX_CHECK_EQUAL(
+      Recount.first, EventCounts.first + 1, "Number of events changed.");
+
+    // Okay, we've added an entry but we don't really want to.  Abort it
+    // explicitly if requested, or simply let the Transaction object "expire."
+    if (ExplicitAbort)
+      Doomed.abort();
+
+    // If now explicit abort requested, Doomed Transaction still ends here
+  }
+
+  // Now check that we're back in the original state.  Note that this may go
+  // wrong if somebody managed to change the table between our two
+  // transactions.
+  work Checkup(conn, "Checkup");
+
+  auto NewEvents{CountEvents(Checkup)};
+  PQXX_CHECK_EQUAL(
+    NewEvents.first, EventCounts.first, "Wrong number of events.");
+
+  PQXX_CHECK_EQUAL(NewEvents.second, 0, "Found unexpected events.");
+}
+
+
+void test_029()
+{
+  connection conn;
+  {
+    nontransaction tx{conn};
+    test::create_pqxxevents(tx);
+  }
+
+  // Test abort semantics, both with explicit and implicit abort
+  Test(conn, true);
+  Test(conn, false);
+}
+
+
+PQXX_REGISTER_TEST(test_029);
+} // namespace