a2/1cases.tex

   1 \subsection{Preflight checklist}
   2 Before actual certification is commenced we perform a manual test using a
   3 checklist.
   4 If any of the checks fail we immediately reject the product.
   5 The checklist is given in the table below. All commands in \texttt{monospace}
   6 are to be run in a terminal. Commands prefixed with a \texttt{\#} should be run
   7 with root permissions. Commands prefixed with a \texttt{\$} should be run with
   8 user permissions.
   9
  10 \begin{longtable}{|l|rp{.8\linewidth}|}
  11         \hline
  12         Check 1 & \multicolumn{2}{l|}{Get the SUT in a workable state.}\\
  13         \hline
  14         \multirow{3}{*}{Course of action}
  15                 & 1. & Import the VirtualBox image into VirtualBox.\\
  16                 & 2. & Boot the vm.\\
  17                 & 3. & Verify the SUT booted successfully and the network modules are
  18                 loaded.\\
  19         \hline
  20         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  21         \hline\hline
  22         Check 2 & \multicolumn{2}{l|}{Verify the SUT is complete.}\\
  23         \hline
  24         \multirow{5}{*}{Course of action}
  25                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  26                 & 2. & Verify the loopback device exists by running
  27                          \texttt{\$ ifconfig}.\\
  28                 & 3. & Verify the \emph{echo-server} is present on the system by running
  29                         \texttt{\$ file code/server/Main.java}\\
  30                 & 4. & Verify \emph{Scapy} is present on the system by running
  31                         \texttt{\$ scapy}.\\
  32                 & 5. & Verify all scripts used for testing are present on the system.\\
  33         \hline
  34         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  35         \hline\hline
  36         Check 3 & \multicolumn{2}{l|}{Initialize the testing environment..}\\
  37         \hline
  38         \multirow{6}{*}{Course of action}
  39                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  40                 & 2. & Setup iptables by executing
  41                         \texttt{\# code/iptables.sh}~\footnote{The IPTables script ensures
  42                         that the OS does not drop packets due to an the unknown source.}\\
  43                 & 3. & Navigate to the working directory by running
  44                         \texttt{\$ cd /home/student/tt2015}\\
  45                 & 4. & Compile the echo server by running
  46                         \texttt{\# cd code/server \&\& make}\\
  47                 & 5. & Start the echo server by running
  48                         \texttt{\# cd code/server \&\& java Main}\\
  49                 & 6. & Generate all test cases by running
  50                         \texttt{\$ python code/client/gen.py}\\
  51         \hline
  52         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  53         \hline\hline
  54         Check 4 & \multicolumn{2}{l|}{Test the tool environment.}\\
  55         \hline
  56         \multirow{3}{*}{Course of action}
  57                 & 1. & Initialize the SUT as in \emph{Check 3}\\
  58                 & 2. & Execute the test script by running
  59                         \texttt{\# code/client/helloworld.py}\\
  60                 & 3. & Verify the console displays a success message.\\
  61         \hline
  62         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  63         \hline\hline
  64         Check 5 & \multicolumn{2}{l|}{All test inputs and scripts are present.}\\
  65         \hline
  66         \multirow{2}{*}{Course of action}
  67                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  68                 & 2. & Verify that the test generation script is present by running
  69                         \texttt{\$ file code/client/test.py}\\
  70         \hline
  71         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  72         \hline
  73         \caption{Preflight checklist\label{tbl:preflight}}
  74 \end{longtable}
  75
  76 \subsection{Testing of SUT}
  77 The SUT is a series of services for other computer programs with no end-user
  78 facing interface. Therefore the SUT will be tested solely by calling it's
  79 services through various automated scripts. An automated test suite will be
  80 available which executes all these automated scripts and aggregates their
  81 results to asses whether or not the SUT has passed the test.
  82
  83 The implementation of the SUT is tested using black box testing techniques. A
  84 series of tests asses the correctness of the implementation with regards to the
  85 TCP specification. These tests are specified in Table~\textbf{referentie naar
  86 tests-tabel}. The test cases aim to cover the most interesting parts of the TCP
  87 specification.
  88
  89 To cover the TCP specification as complete as possible while still maintaining
  90 a feasible test suite the tests are divided into equivalence partitions. Below
  91 these partitions are given.
  92
  93 \begin{enumerate}
  94         \item \emph{Number of segments} in request~\footnote{A request is
  95                 considered establishing a connection (handshake) and a number of
  96                 payload segments}
  97                 \begin{enumerate}
  98                         \item 0 payload segments
  99                         \item 1 payload segments
 100                         \item n=small payload segments (1 byte)
 101                         \item n=big payload segments (65495 bytes)
 102                 \end{enumerate}
 103         \item \emph{source port}
 104                 \begin{enumerate}
 105                         \item Correct
 106                         \item Incorrect
 107                 \end{enumerate}
 108         \item \emph{destination port}
 109                 \begin{enumerate}
 110                         \item Correct
 111                         \item Incorrect
 112                 \end{enumerate}
 113         \item Bit errors in \emph{payload}
 114                 \begin{enumerate}
 115                         \item Correct payload
 116                         \item Payload with bit flips that do not show in checksum
 117                         \item Payload with bit flips that do show in checksum
 118                 \end{enumerate}
 119         \item \emph{checksum}
 120                 \begin{enumerate}
 121                         \item Correct
 122                         \item Incorrect
 123                 \end{enumerate}
 124         \item \emph{Segment order}
 125                 \begin{enumerate}
 126                         \item Correct
 127                         \item Out of order
 128                         \item Missing Segments
 129                 \end{enumerate}
 130 \end{enumerate}
 131
 132 These partitions were chosen since they correspond to key parts of the TCP
 133 specification.
 134
 135 TCP segments are send over a TCP connection from a \emph{source} to a \emph{destination port}. Therefore segments which are received that have a
 136 source or destination port set to an incorrect value should not be regarded
 137 as segments belonging to the connection by the SUT.
 138
 139 TCP uses a \emph{checksum} to catch any error introduced in headers, when this
 140 checksum does not match the actual computed checksum the SUT should
 141 disregard the received segment.
 142
 143 The TCP checksum is also an inherently weak one, as it is simply the
 144 bitwise negation of the addition, in ones complement arithmetic,
 145 of all 16 bit words in the header and data of the segment (excluding the
 146 checksum itself). Therefore any \emph{bit error} where the ones complement value
 147 of one word
 148 increases by one, and the value of another decreases by one, is undetected.
 149 The SUT should exhibit the same behavior and accept packets where these type
 150 of bit errors occur.
 151
 152 TCP guarantees that segments are delivered \emph{in order}
 153 ,even when they are received
 154 out of order and that missing segments are resend. The SUT should
 155 exhibit the same behavior. If segments are received out of order it should
 156 either reassemble them when the missing packet has arrived or request them to
 157 be resend when the  Missing segments should be re-requested (by ACK-ing
 158 the correct sequence number).
 159
 160 \bigskip
 161
 162 Partitions 2 to 6 are tested using pairwise testing to keep the number of test
 163 cases feasible. The pairs are then all *except some where it does not make sense
 164 to do so) tested with the different request sizes of partition 1.
 165
 166 This is expressed in Table~\ref{table:testpairs}. In this table the first five
 167 columns represent the different options for the partitions 2 to 6 of the above
 168 enumeration. The last four columns are the different number segments as
 169 described in the partition 1 of the above enumeration. These cells identify
 170 individual test cases by a number. An \xmark in the cell indicates that this
 171 test case can not be created as it is not possible with that number of segments
 172 (eg. sending segments out of order when the number of segments is 1).
 173
 174 \newcounter{TCC}
 175 \setcounter{TCC}{1}
 176 \newcommand{\doTCC}{\theTCC \stepcounter{TCC}}
 177 \begin{table}[H]
 178         \centering
 179         \begin{tabular}{|l|l|l|l|l|l||l|l|l|l|}
 180                 \hline
 181                 & \multicolumn{9}{c|}{\textbf{Partition}}\\
 182                 \hline
 183                 & 4 & 5 & 3 & 6 & 2 & 1a & 1b & 1c & 1d\\
 184                 \hline\hline
 185                 \multirow{9}{*}{Instance}
 186                 & a & a & a & a & a & \doTCC & \doTCC & \doTCC & \doTCC\\
 187                 & a & b & b & c & b & \xmark & \xmark & \doTCC & \doTCC\\
 188                 & c & a & b & a & b & \xmark & \xmark & \doTCC & \doTCC\\
 189                 & c & b & a & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 190                 & b & a & b & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 191                 & b & b & a & b & b & \xmark & \xmark & \doTCC & \doTCC\\
 192                 & c & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 193                 & b & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 194                 & a & b & b & b & a & \xmark & \xmark & \doTCC & \doTCC\\
 195                 \hline
 196 \end{tabular}
 197 \caption{Combinations of test cases}
 198 \label{table:testpairs}
 199 \end{table}
 200
 201 \subsection{Quality, completeness and coverage of tests}
 202
 203 The network packets used in testing are constructed from prerecorded, known to
 204 be correct, network traffic. These packets are then modified with well used and
 205 field tested tools. Due to this the chance of errors in the test cases is quite
 206 low. However, no formal proof of correctness of the test cases is present, this
 207 means that any defects found might not be the result of a fault in the SUT.
 208 Therefore detected defects should only indicate there is a high chance that
 209 there is a fault in the SUT and can not result directly in the conclusion that
 210 there actually is one.
 211
 212 \bigskip
 213
 214 Due to the nature of black-box testing coverage of the code in the
 215 implementation of the SUT is unknown. However completeness of the tests over
 216 the specification of the SUT can be assessed.
 217
 218 \bigskip
 219
 220 Due to the clear and exhaustive specification of TCP the completeness of the
 221 test suite can be clearly assessed.
 222
 223 As always, $100\%$ completeness is not feasible, therefore test cases are
 224 carefully selected to cover the most interesting parts of the TCP specification
 225 to ensure a complete but feasible test suite.
 226
 227 To further increase the coverage of the test suites tests are randomized. The
 228 tests which test the handling of \emph{bit errors}, changes in the \emph{packet
 229 order} and \emph{dropped packets} randomize where they introduce an error. The
 230 test suite runs these tests multiple times to increase the likelihood that they
 231 discover a fault which is only present when an error occurs in a certain
 232 position.
 233
 234 To further decrease the number of tests needed test cases are divided into
 235 equivalence partitions and the combination of cases as described in
 236 Table~\ref{table:testpairs} ensures that all partitions are
 237 covered and the number of individual tests is still feasible.
 238
 239
 240 %
 241 % wat ik ook probeer ik krijg de eerste collum
 242 % zijn tekst niet verticaal gecentered
 243 %
 244
 245
 246 \subsection{Test cases}
 247
 248 Before every test case use the following steps to initialize the testing environment.
 249
 250 \begin{enumerate}
 251         \item Boot the vm using VirtualBox.
 252         \item Setup iptables by executing \texttt{\# code/iptables.sh}
 253         \item Navigate to the working directory by running \texttt{\$ cd /home/student/tt2015}
 254         \item Start the echo server by running \texttt{\# cd code/server \&\& java Main}
 255 \end{enumerate}
 256
 257 \begin{longtable}{|p{.2\linewidth}|p{.8\linewidth}|}
 258         \hline
 259         Nr & 1 \\\hline
 260         Title & Single valid request with 1byte payload. \\\hline
 261         Input & Generated packets. \\\hline
 262         Expected output & Packets echoed back by Echo-Server. \\\hline
 263         \multirow{2}{*}{Course of action}
 264  & 1. Use the steps listed above in order to start the SUT. \\
 265  & 2. Execute the script by running \texttt{\# code/client/tests/1.py} \\\hline
 266         Valid trace & Verify that the script prints 'Success'. \\\hline
 267         \hline
 268
 269         Nr & 2 \\\hline
 270         Title & Single valid request with 65495bytes payload. \\\hline
 271         Input & Generated packets. \\\hline
 272         Expected output & Packets echoed back by Echo-Server. \\\hline
 273         \multirow{2}{*}{Course of action}
 274         & 1. Use the steps listed above in order to start the SUT. \\
 275         & 2. Execute the script by running \texttt{\# code/client/tests/2.py} \\\hline
 276         Valid trace & Verify that the script prints 'Success'. \\\hline
 277         \hline
 278
 279         Nr & 3 \\\hline
 280         Title & 5 valid requests with 1byte payload. \\\hline
 281         Input & Generated packets. \\\hline
 282         Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 283         \multirow{2}{*}{Course of action}
 284         & 1. Use the steps listed above in order to start the SUT. \\
 285         & 2. Execute the script by running \texttt{\# code/client/tests/3.py} \\\hline
 286         Valid trace & Verify that the script prints 'Success'. \\\hline
 287         \hline
 288
 289         Nr & 4 \\\hline
 290         Title & 5 valid requests with 65495bytes payload. \\\hline
 291         Input & Generated packets with 65495bytes payload. \\\hline
 292         Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 293         \multirow{2}{*}{Course of action}
 294         & 1. Use the steps listed above in order to start the SUT. \\
 295         & 2. Execute the script by running \texttt{\# code/client/tests/4.py} \\\hline
 296         Valid trace & Verify that the script prints 'Success'. \\\hline
 297         \hline
 298
 299         Nr & 5 \\\hline
 300         Title & 5 valid requests with 1byte payload sent out of order. \\\hline
 301         Input & Generated packets with 1byte payload, two packets are swapped in position. \\\hline
 302         Expected output & All requests sent up to and including
 303          the swapped packet with the lowest sequence number, the remaining packets are dropped. \\\hline
 304         \multirow{2}{*}{Course of action}
 305         & 1. Use the steps listed above in order to start the SUT. \\
 306         & 2. Execute the script by running \texttt{\# code/client/tests/5.py} \\\hline
 307         Valid trace & Verify that the script prints 'Success'. \\\hline
 308         \hline
 309 \end{longtable}
 310
 311 %\begin{tabularx}{\linewidth}{| l | X|}
 312 %\hline
 313 %Nr & 1 \\\hline
 314 %Title & Single valid request. \\\hline
 315 %Input & Pcap file with prerecorded valid packets. \\\hline
 316 %Expected output & Pcap file with valid response to request. \\\hline
 317 %Course of action & \begin{enumerate}
 318 %       \item Execute \emph{./scripts/tests/case1-single-valid.sh}
 319 %       \item Load \emph{output/case1.pcap} with ...
 320 %\end{enumerate} \\\hline
 321 %Valid trace & \begin{enumerate}
 322 %       \item \textbf{Hier packets benoemen?}
 323 %\end{enumerate} \\\hline
 324 %\end{tabularx}
 325 %
 326 %\begin{tabularx}{\linewidth}{| l | X|}
 327 %       \hline
 328 %       Nr & 2 \\\hline
 329 %Title & Single request with corrupted checksum. \\\hline
 330 %       Input & Pcap file used as \emph{test-case 1} input. \\\hline
 331 %       Expected output & No response from SUT, logs with rejected packets. \\\hline
 332 %       Course of action & \begin{enumerate}
 333 %               \item Load input pcap file into ....
 334 %               \item Corrupt checksum of loaded packets.
 335 %               \item Save resulting packets as pcap file.
 336 %               \item Load new pcap file into ...
 337 %               \item Replay new pcap file.
 338 %               \item Record SUT response using...
 339 %               \item Extract log with rejected packets.
 340 %               \item Save recorded packets as a pcap file.
 341 %               \item Analyze packets in resulting file.
 342 %       \end{enumerate} \\\hline
 343 %       Valid trace & \begin{enumerate}
 344 %               \item \textbf{Aangeven welke packets corrupted zijn?}
 345 %       \end{enumerate} \\\hline
 346 %\end{tabularx}
 347 %\end{table}