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

tests/pgintegration/DbTest.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <gtest/gtest.h>
+#include <memory>
+#include <QString>
+
+#include "Pgsql_Connection.h"
+
+namespace pgtest {
+
+/// Fixture giving every test its own database cloned from the template.
+class DbTest : public ::testing::Test {
+protected:
+    void SetUp() override;
+    void TearDown() override;
+
+    Pgsql::Connection& conn() { return *conn_; }
+    QString dbName() const { return dbName_; }
+    QString dbUrl() const;
+
+private:
+    QString dbName_;
+    std::unique_ptr<Pgsql::Connection> conn_;
+};
+
+} // namespace pgtest