Add explenation on randomisation

[tt2015.git] / a2 / 1cases.tex

diff --git a/a2/1cases.tex b/a2/1cases.tex
index e488ba3..69f8168 100644 (file)
--- a/a2/1cases.tex
+++ b/a2/1cases.tex
@@ -181,8 +181,8 @@ This is expressed in Table~\ref{table:testpairs}.
                & 4 & c & b & a & c & a & \xmark & \xmark & \doTCC & \doTCC\\
                & 5 & b & a & b & c & a & \xmark & \xmark & \doTCC & \doTCC\\
                & 6 & b & b & a & b & b & \xmark & \xmark & \doTCC & \doTCC\\
                & 4 & c & b & a & c & a & \xmark & \xmark & \doTCC & \doTCC\\
                & 5 & b & a & b & c & a & \xmark & \xmark & \doTCC & \doTCC\\
                & 6 & b & b & a & b & b & \xmark & \xmark & \doTCC & \doTCC\\

-               & 7 & c & b & b & a & b & \doTCC & \doTCC & \doTCC & \doTCC\\
-               & 8 & b & b & b & a & b & \doTCC & \doTCC & \doTCC & \doTCC\\
+               & 7 & c & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
+               & 8 & b & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\

                & 9 & a & b & b & b & a & \xmark & \xmark & \doTCC & \doTCC\\
                \hline
 \end{tabular}
                & 9 & a & b & b & b & a & \xmark & \xmark & \doTCC & \doTCC\\
                \hline
 \end{tabular}


@@ -214,7 +214,14 @@ test suite can be clearly assessed.
 
 As always, $100\%$ completeness is not feasible, therefore test cases are
 carefully selected to cover the most interesting parts of the TCP specification
 
 As always, $100\%$ completeness is not feasible, therefore test cases are
 carefully selected to cover the most interesting parts of the TCP specification

-to ensure a test suite.
+to ensure a complete but feasible test suite.
+
+To further increase the coverage of the test suites tests are randomized. The
+tests which test the handling of \emph{bit errors}, changes in the \emph{packet
+order} and \emph{dropped packets} randomize where they introduce an error. The
+test suite runs these tests multiple times to increase the likelihood that they
+discover a fault which is only present when an error occurs in a certain
+position. 

 
 To further decrease the number of tests needed test cases are divided into
 equivalence partitions and the combination of cases as described in 
 
 To further decrease the number of tests needed test cases are divided into
 equivalence partitions and the combination of cases as described in