In this directory, you should write the program `wcat.c` and compile it into
the binary `wcat'.

After doing so, you can run the tests from this directory by running the
`run-tests.sh` script. If all goes well, you will see:

```sh
prompt> ../../tester/run-tests.sh
test 1: passed
test 2: passed
test 3: passed
test 4: passed
test 5: passed
test 6: passed
test 7: passed
prompt>
```