doc: document optionally required packages

- tshark and valgrind are required but only if you enable those
  features during test runs.

Signed-off-by: Christian Hopps <chopps@labn.net>

diff --git a/doc/developer/topotests.rst b/doc/developer/topotests.rst
index 7b1fde7b53243acbc9f59b32628e3184c3c43b18..f44cf9df985d2b30af04dfee489893d92e832c8b 100644 (file)
--- a/doc/developer/topotests.rst
+++ b/doc/developer/topotests.rst
@@ -17,13 +17,23 @@ Tested with Ubuntu 20.04,Ubuntu 18.04, and Debian 11.
 Instructions are the same for all setups (i.e. ExaBGP is only used for
 BGP tests).
 
+Tshark is only required if you enable any packet captures on test runs.
+
+Valgrind is only required if you enable valgrind on test runs.
+
 Installing Topotest Requirements
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 .. code:: shell
 
-   apt-get install gdb iproute2 net-tools python3-pip \
-      iputils-ping valgrind
+   apt-get install \
+       gdb \
+       iproute2 \
+       net-tools \
+       python3-pip \
+       iputils-ping \
+       tshark \
+       valgrind
    python3 -m pip install wheel
    python3 -m pip install 'pytest>=6.2.4'
    python3 -m pip install 'pytest-xdist>=2.3.0'