net/coap: Packet API function to add Uri-Query option

[kb2ma]

Contribution description

#9309 is a tracking issue for the migration of CoAP Option functionality to the nanocoap Packet API. The last remaining function for the migration is gcoap_add_qstring(). This PR adds coap_opt_add_uquery() to nanocoap, renamed to be more descriptive and conform to the Packet API naming convention. We plan to create a follow-on PR to migrate existing uses and deprecate gcoap_add_qstring().

Testing procedure

Build the documentation to ensure the new function appears as part of the Options Write Packet API section of the nanocoap documentation. Also run the gcoap unit tests.

Issues/PRs references

Part of #9309.

[leandrolanzieri]

It looks good. The unit tests still pass. Just a small typo. Also, the prefix on the second commit is a bit misleading, as you are using the new query function in the unit test and not in gcoap itself.

I think it also would be good to modify nanocoap's query unit tests to use this function now.

Unit test result

> make tests-gcoap test
Building application "tests_unittests" for "native" with MCU "native".

"make" -C /home/leandro/Work/RIOT/boards/native
"make" -C /home/leandro/Work/RIOT/boards/native/drivers
"make" -C /home/leandro/Work/RIOT/core
"make" -C /home/leandro/Work/RIOT/cpu/native
"make" -C /home/leandro/Work/RIOT/cpu/native/periph
"make" -C /home/leandro/Work/RIOT/cpu/native/stdio_native
"make" -C /home/leandro/Work/RIOT/cpu/native/vfs
"make" -C /home/leandro/Work/RIOT/drivers
"make" -C /home/leandro/Work/RIOT/drivers/periph_common
"make" -C /home/leandro/Work/RIOT/sys
"make" -C /home/leandro/Work/RIOT/sys/div
"make" -C /home/leandro/Work/RIOT/sys/embunit
"make" -C /home/leandro/Work/RIOT/sys/evtimer
"make" -C /home/leandro/Work/RIOT/sys/fmt
"make" -C /home/leandro/Work/RIOT/sys/luid
"make" -C /home/leandro/Work/RIOT/sys/net/application_layer/gcoap
"make" -C /home/leandro/Work/RIOT/sys/net/application_layer/nanocoap
"make" -C /home/leandro/Work/RIOT/sys/net/crosslayer/inet_csum
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/netapi
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/netif
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/netif/hdr
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/netreg
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/network_layer/icmpv6
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/network_layer/ipv6
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/network_layer/ipv6/hdr
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/network_layer/ipv6/nib
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/network_layer/ndp
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/pkt
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/pktbuf
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/pktbuf_static
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/sock
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/sock/udp
"make" -C /home/leandro/Work/RIOT/sys/net/gnrc/transport_layer/udp
"make" -C /home/leandro/Work/RIOT/sys/net/link_layer/l2util
"make" -C /home/leandro/Work/RIOT/sys/net/netif
"make" -C /home/leandro/Work/RIOT/sys/net/network_layer/icmpv6
"make" -C /home/leandro/Work/RIOT/sys/net/network_layer/ipv6/addr
"make" -C /home/leandro/Work/RIOT/sys/net/network_layer/ipv6/hdr
"make" -C /home/leandro/Work/RIOT/sys/net/sock
"make" -C /home/leandro/Work/RIOT/sys/net/transport_layer/udp
"make" -C /home/leandro/Work/RIOT/sys/posix/inet
"make" -C /home/leandro/Work/RIOT/sys/random
"make" -C /home/leandro/Work/RIOT/sys/random/tinymt32
"make" -C /home/leandro/Work/RIOT/sys/test_utils/interactive_sync
"make" -C /home/leandro/Work/RIOT/sys/xtimer
"make" -C /home/leandro/Work/RIOT/tests/unittests/tests-gcoap
   text	  data	   bss	   dec	   hex	filename
  54727	  1284	 47840	103851	 195ab	/home/leandro/Work/RIOT/tests/unittests/bin/native/tests_unittests.elf
r
/home/leandro/Work/RIOT/tests/unittests/bin/native/tests_unittests.elf  
RIOT native interrupts/signals initialized.
LED_RED_OFF
LED_GREEN_ON
RIOT native board initialized.
RIOT native hardware initialization complete.

main(): This is RIOT! (Version: 2020.04-devel-110-g8ccc4-coap/add_uquery_opt)
Help: Press s to start test, r to print it is ready
READY
s
START
...........
OK (11 tests)

[kb2ma]

Also, the prefix on the second commit is a bit misleading, as you are using the new query function in the unit test and not in gcoap itself.

So, change the second commit to this?

net/coap: use new function to add query option

I think it also would be good to modify nanocoap's query unit tests to use this function now.

I like test_nanocoap__get_query() as is because it's the only test with an option string that does not include the delimiter. How about if I replace the contents of test_nanocoap__get_multi_query() with
test_gcoap__client_get_query(), and drop that test in gcoap? [edit: Might rework the second commit above based on suggestion.]

In general as a result of #9309 there's a larger issue of what tests belong in nanocoap vs. gcoap. nanocoap also has become so large that its tests can be sub-divided along functional lines in the future.

[leandrolanzieri]

How about if I replace the contents of test_nanocoap__get_multi_query() with
test_gcoap__client_get_query(), and drop that test in gcoap? [edit: Might rework the second commit above based on suggestion.]

I agree, let's do it this way, as test_gcoap__client_get_query() is now testing mostly nanocoap functionalities.

[kb2ma]

Pushed test fixups as discussed. There are four commits now. If it looks good, I will squash down to these three:

1. net/coap: move/rename function to add query option
2. net/nanocoap: use new function in query test
3. net/gcoap: remove test migrated to nanocoap

[leandrolanzieri]

Changes look good. Unit tests for nanocoap and gcoap still pass. ACK.

@kb2ma please squash down to the commits you mentioned.

[kb2ma]

Squashed and rebased due to recent changes for Kconfig.