Added prepared_statement::execute tests

Fixed bug in prepare_statement (was not reading metadata packets after
the prepared statement response)
Added stringize()
Now execute() explicitly checks the number of parameters and issues an
error if they don't match the expected count

test/integration/execute_statement.cpp

@@ -0,0 +1,56 @@
+/*
+ * execute_statement.cpp
+ *
+ *  Created on: Feb 5, 2020
+ *      Author: ruben
+ */
+
+#include "integration_test_common.hpp"
+#include <forward_list>
+
+using namespace mysql::test;
+using mysql::value;
+using mysql::Error;
+
+namespace
+{
+
+struct ExecuteStatementTest : public IntegTestAfterHandshake
+{
+};
+
+TEST_F(ExecuteStatementTest, IteratorsSyncErrc_OkNoParams)
+{
+	std::forward_list<value> params;
+	auto stmt = conn.prepare_statement("SELECT * FROM empty_table");
+	auto result = stmt.execute(params.begin(), params.end(), errc, info);
+	validate_no_error();
+	EXPECT_TRUE(result.valid());
+}
+
+TEST_F(ExecuteStatementTest, IteratorsSyncErrc_OkWithParams)
+{
+	std::forward_list<value> params { value("item"), value(42) };
+	auto stmt = conn.prepare_statement("SELECT * FROM empty_table WHERE id IN (?, ?)");
+	auto result = stmt.execute(params.begin(), params.end(), errc, info);
+	validate_no_error();
+	EXPECT_TRUE(result.valid());
+}
+
+TEST_F(ExecuteStatementTest, IteratorsSyncErrc_Error)
+{
+	std::forward_list<value> params { value("item") };
+	auto stmt = conn.prepare_statement("SELECT * FROM empty_table WHERE id IN (?, ?)");
+	auto result = stmt.execute(params.begin(), params.end(), errc, info);
+	validate_sync_fail(Error::wrong_num_params, {"param", "2", "1", "statement", "execute"});
+	EXPECT_FALSE(result.valid());
+}
+
+// prepared_statement::execute
+//    OK, no params
+//    OK, with params
+//    OK, select, insert, update, delete
+//    Error, wrong number of parameters
+//    Collection version
+
+}