Add framework for executing tests against multiple postgresql versions using docker compose.

tests/pgintegration/DbTest.cpp

@@ -0,0 +1,55 @@
+#include "DbTest.h"
+#include "PgTestEnvironment.h"
+
+#include <atomic>
+#include <stdexcept>
+
+namespace pgtest {
+
+namespace {
+std::atomic<int> g_counter{0};
+}
+
+QString DbTest::dbUrl() const
+{
+    return urlForDb(dbName_);
+}
+
+void DbTest::SetUp()
+{
+    if (!available())
+        GTEST_SKIP() << "TEST_DATABASE_URL not set or template database unavailable";
+
+    dbName_ = QString("t_%1_%2").arg(g_counter++).arg(processId());
+    try {
+        {
+            Pgsql::Connection admin;
+            admin.connect(*baseUrl());
+            admin.query(QString("CREATE DATABASE %1 TEMPLATE %2")
+                        .arg(quoteIdent(dbName_), quoteIdent(templateDbName())));
+        }
+        conn_ = std::make_unique<Pgsql::Connection>();
+        conn_->connect(dbUrl());
+    }
+    catch (const std::exception &e) {
+        FAIL() << "Creating test database failed: " << e.what();
+    }
+}
+
+void DbTest::TearDown()
+{
+    conn_.reset();
+    if (dbName_.isEmpty())
+        return;
+    try {
+        Pgsql::Connection admin;
+        admin.connect(*baseUrl());
+        admin.query(QString("DROP DATABASE IF EXISTS %1 WITH (FORCE)").arg(quoteIdent(dbName_)));
+    }
+    catch (const std::exception &e) {
+        ADD_FAILURE() << "Dropping test database failed: " << e.what();
+    }
+    dbName_.clear();
+}
+
+} // namespace pgtest