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The test process consists of several stages. The results of the first stage,
planning, are descibed in this document. On the basis of this document actual
test cases will be designed. Afterwards the actual tests will be implemented
and executed. The results of these tests will then be evaluated against the
-exit criteria (see Section~\ref{sec:exitcriteria}) and depending on the outcome
-of these evaluations further tests might be deemed necessary.
+exit criteria found in Section~\ref{sec:exitcriteria} and depending on the
+outcome of these evaluations further tests might be deemed necessary.
\subsection{Quality Characteristics}
The quality characteristics that are to be tested are described using the
to the SUT.
\begin{itemize}
\item \textbf{Functional suitability}\\
- As descibed in Section~\ref{sec:risks} the SUT is core functioanlity of the
- networking capable system. Because many other systems running on the system
- could rely on it it is very important that the SUT is functionaly suitable.
- Therefore all three subcharacteristics of Functional Suitability
- (\textit{Functional completeness, Functional correctness, Functional
- appropriateness}) are of vital importance. As was previously mentioned in
- Section~\ref{sec:risks} extra emphasis should be placed on testing
- \emph{Functional Correctness} as recovery from Failures in
+ As described in Section~\ref{sec:risks} the SUT is core functionality of
+ the networking capable system. Because many other systems running on the
+ system could rely on it it is very important that the SUT is functionality
+ suitable. Therefore all three sub characteristics of Functional
+ Suitability (\textit{Functional completeness, Functional correctness,
+ Functional appropriateness}) are of vital importance. As was previously
+ mentioned in Section~\ref{sec:risks} extra emphasis should be placed on
+ testing \emph{Functional Correctness} as recovery from Failures in
computer-to-computer systems is problematic.
+ \item \textbf{Performance efficiency} \label{sec:perf_eff}\\
+ As the SUT runs as a service on a system with other programs it must have
+ efficient \emph{resource utilisation}. It can not contain any memory leaks
+ or use other resources more than necessary.
+ \item \textbf{Compatibility}\\
+ \emph{Interoperability} is the key feature of the SUT as it's purpose is to
+ communicate with other systems implementing the TCP protocol. Therefore it
+ is of vital importance that the SUT implements the TCP protocol correctly.
+ Furthermore it is very important that the SUT can \emph{co-exist} with
+ other programs on the system it runs on, since it is used as a service by
+ those programs. This means that the SUT has to handle preemption as well as
+ having multiple programs requesting it's services at once.
+ \item \textbf{Reliability}\\
+ As stated before, the SUT is used as a core service, this means it has to
+ be very \emph{mature}. It needs to behave as expected under normal working
+ conditions. As it can continually be requested the SUT needs to have
+ constant
+ \emph{availability}. As the SUT relies on a potentially unreliable channel
+ to send and receive data it needs to be \emph{fault tolerant}. The SUT
+ needs to properly handle errors in received data or complete unavailability
+ of the underlying channel.
\end{itemize}
+This leaves four categories which are not relevant the SUT. Below we will
+shortly discuss per category why these are not relevant. \emph{Maintainability}
+is an important aspect of any software system, however for the SUT it is not a
+core aspect, as it is first and foremost of importance that the implementation
+is correct, furthermore TCP does not change often. \emph{Usability} isn't a
+core aspect either, as the SUT is not used directly by humans, but is a service
+which is addressed when another program needs it. \emph{Portability} isn't
+either as the SUT is installed on a system once and intended to work on that
+system. \emph{Security} isn't a feauture of the SUT either, systems using the
+SUT can add their own security mechanisms on top of it.
+
\subsubsection{Quality in use}
+Quality in use is dived into five subcategories. Below we will discuss the
+categories which are relevant to the SUT.
+\begin{itemize}
+ \item \textbf{Effectiveness}\\
+ This is the core aspect of the SUT, users (other programs) need to be able
+ to effectively use the SUT to send and receive data.
+ \item \textbf{Efficiency}\\
+ This issue has already been covered above under
+ ``performance efficiency''~\ref{sec:perf_eff}.
+ \item \textbf{Satisfaction}\\
+ It is important that programs using the SUT can \emph{trust} that the SUT
+ provides the promised services. This means that data is send and received
+ reliably and the SUT provides clear and unambiguous errors when this
+ service
+ can not be provided.
+ \item \textbf{Context Coverage}\\
+ The SUT needs to behave as expected in all specified contexts
+ (\emph{context completeness}).
+\end{itemize}
+This leaves \emph{freedom from risk}, which we consider not relevant as the SUT
+itself does not pose any risks, and correct implementation (which is covered in
+the other categories) gives clear guarantees to programs using the services of
+the SUT.
+
+\subsection{Levels and types of testing} \label{levels}
+The client will deliver a product for certification. This means our team will
+only conduct \emph{acceptance testing} and assume that the client who requested
+certification has conducted \emph{unit}, \emph{module} and \emph{integration testing}.
+We will only be conducting \emph{black-box testing} and the client is not required to handover any
+source-code.
+
+Initially we will conduct a few basic \emph{manual tests} based on
+experience acquired from previous certification requests (\emph{error guessing}). If
+the product fails these basic tests we immediately reject it and seize all further
+activities.
+
+If the product is not rejected after the basic \emph{manual tests} we will proceed with the
+second stage of testing. For these follow-up tests we will use \emph{equivalence partitioning}
+to reduce the number of test cases. Every test case will result in a test report.
+If any of the test cases fail the product is rejected. In order to deliver
+usable feedback to the client we will still produce a test report.
+
+\subsubsection{Manual tests}
+
+The basic tests mentioned in Section \ref{levels} are conducted using a
+checklist. If any of the checks fail we immediately reject the product.
+
+\begin{enumerate}
+ \item Is the product complete?
+ \item Does the product come with a manual or quick start guide?
+ \item Is it possible to get the product in a usable state?
+ \item Can we use the product to initiate a connection in a corruption
+ free
+ environment?
+\end{enumerate}
+
+These\emph{ manual tests} are performed in order to ensure that the client has delivered a usable product.
+
+\subsubsection{Test generation}
+
+For the second state of testing we first use \emph{equivalence partitioning} to reduce the
+overall number of test cases as mentioned in Section \ref{levels}. At the highest level we can define the following equivalent \emph{input classes} for the SUT.
+
+\begin{enumerate}
+ \item Valid requests:
+ \begin{enumerate}
+ \item Single request.
+ \item Multiple requests.
+ \end{enumerate}
+ \item Invalid requests:
+ \begin{enumerate}
+ \item Single request.
+ \item Multiple requests.
+ \end{enumerate}
+\end{enumerate}
+
+For these requests we can introduce more cases by applying \emph{equivalence partitioning}
+to the different packets that are sent during one request.
+
+\begin{enumerate}
+ \item Packets received in order.
+ \item Packets received out of order.
+\end{enumerate}
+
+For each individual packet we can specify the follow \emph{equivalent classes}.
+
+\begin{enumerate}
+ \item Valid packet.
+ \item Corrupted packet.
+ \item Missing packets.
+\end{enumerate}
+
+A \emph{decision table} is used in order to ensure all different equivalent classes are covered in our tests.
+Valid packets can only exist in one form, the valid form and there is
+no need to divide these into additional classes.
+For the invalid packets we will construct a test case where only one parameter is made invalid.
+For the invalid value of this parameter we use \emph{boundary value analysis} to reduce the total
+number of test cases.
+The SUT input parameters correspond to different fields in the network packets.
+The following fields and there boundary values are considered during the testing.
+
+\begin{enumerate}
+ \item Checksum: valid, invalid.
+ \item Header: valid, even or odd number of bits corrupted.
+ \item Payload: valid, even or odd number of bits corrupted.
+\end{enumerate}
+
+\subsubsection{Test environment and automatization}
+\label{section:testenv}
+%%%Java\footnote{\url{http://www.java.com}} TCP driven echo server that executed
+%%%on a virtualized Ubuntu system\footnote{\url{http://www.ubuntu.com}} running on
+%%%the error behaviour custom iptables output policies have to be set
+%%%Listing~\ref{listing:iptables}. This is needed because the kernel by default
+%%%closes all connections from unknown sources and the manually created TCP
+%%%packets used in testing the implementation are from a source unknown to the
+%%%kernel.
+%%%
+%%%\begin{lstlisting}[label={listing:iptables},caption={settings iptables}]
+%%%Chain OUTPUT (policy ACCEPT)
+%%%target prot opt source destination
+%%%ACCEPT tcp -- anywhere anywhere tcp flags:PSH/PSH
+%%%DROP tcp -- anywhere anywhere tcp flags:RST/RST
+%%%\end{lstlisting}
+%%%All the tools we are going to use together with the SUT gives us the following
+%%%collection of software.
+
+\begin{enumerate}
+ \item Windows, used as a host OS.
+ \item Ubuntu, used as the guest OS running the SUT.
+ \item VirtualBox, used to run the guest OS containing the SUT.
+ \item Wireshark, used on the guest in order to capture and analyze network
+ traffic.
+ \item Bit-Twist, used to prepare network packets.
+\end{enumerate}
+
+All test will be conducted in a virtual environment. We will use VirtualBox to
+run a Linux distribution with the product installed.
+The Linux distribution in question is Ubuntu.
+All the tests are performed from within the VirtualBox environment.
+When testing network transmissions we will only analyze the packets sent/received to/from the SUT. The host system is disconnected from the Internet or any other network in
+order to prevent unnecessary traffic.
+% Dit is niet nodig omdat het via loopback gaat
+% Zeker weten? de SUT ontvangt ook niet loopback packets toch?
+
+For each test case (except for the \emph{manual tests}) a file containing previously
+captured network traffic will be replayed using Wireshark. We will use Bit-Twist
+to update the prepared packets with the MAC address of the guest network
+adapter. The response packets coming from the SUT will be recorded and
+analyzed and validated according to the \textit{RFC793} specification.
+The valid packets are build manually from the \textit{RFC793} specification.
+Invalid packets are generated from this valid traffic using Bit-Twist.
+The boundary values for the different parameters (fields in packets) are determined by hand. Automated scripts are used in order to generate packets with some fields replaced with these
+\emph{boundary values}.
+
+% Dit is mooier om footnotes van te maken en te gebruiken als het voor het
+% eerst gerefereerd is
+% WAT HOE?
+\begin{enumerate}
+ \item VirtualBox, https://www.virtualbox.org/
+ \item Whireshark, https://www.wireshark.org/
+ \item Bit-Twist, http://bittwist.sourceforge.net/
+\end{enumerate}
repositories / tt2015.git / blobdiff