Simple NFT MONITOR Testsuite
============================

The purpose of this suite of tests is to assert correct 'nft monitor' output for
known input. The suite consists of the single shell script 'run-tests.sh' which
performs the tests and a number of test definition files in 'testcases/'. The
latter have to be suffixed '.t' in order to be recognized as such.

Test Case Syntax
----------------

Each testcase defines a number of commands to pass on to 'nft' binary and an
associated 'nft monitor' output definition. Prerequisites for each command have
to be established manually, i.e. in order to test monitor output when adding a
chain, the table containing it has to be created first. In between each
testcase, rule set is flushed completely.

Input and output lines are prefixed by 'I' and 'O', respectively. The prefix has
to be separated from the rest of the line by whitespace. Consecutive input lines
are passed to 'nft' together, hence lead to a single transaction.

Since in most cases output should be equal to input, there is a shortcut: If a
line consists of 'O -' only, the test script uses all previous input lines as
expected output directly.

Empty lines and those starting with '#' are ignored.

Test Script Semantics
---------------------

The script iterates over all test case files, reading them line by line. It
assumes that sections of 'I' lines alternate with sections of 'O' lines. After
stripping the prefix, each line is appended to a temporary file. There are
separate files for input and output lines.

If a set of input and output lines is complete (i.e. upon encountering either a
new input line or end of file), a testrun is performed: 'nft monitor' is run in
background, redirecting the output into a third file. The input file is passed
to 'nft -f'. Finally 'nft monitor' is killed and it's output compared to the
output file created earlier. If the files differ, a unified diff is printed and
test execution aborts.

After each testrun, input and output files are cleared.

Note: Running 'nft monitor' in background is prone to race conditions. Hence
an artificial delay is introduced before calling 'nft -f' to allow for 'nft
monitor' to complete initialization and another one before comparing the output
to allow for 'nft monitor' to process the netlink events.