Add a simple conference test with 3 friends.

[iphydf]

This tests that a message from tox1 is relayed via tox2 to tox3 when tox1
and tox3 are not friends.

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This change is 

[zoff99]

Review status: 0 of 2 files reviewed at latest revision, 4 unresolved discussions, some commit checks failed.

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auto_tests/simple_conference_test.c, line 121 at r1 (raw file):

    fprintf(stderr, "Waiting for toxes to come online");

    while (!state1.self_online || !state2.self_online || !state3.self_online) {

loop may never end

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auto_tests/simple_conference_test.c, line 135 at r1 (raw file):

    fprintf(stderr, "Waiting for friends to connect");

    while (!state1.friend_online || !state2.friend_online || !state3.friend_online) {

loop may never end

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auto_tests/simple_conference_test.c, line 165 at r1 (raw file):

    fprintf(stderr, "Waiting for invitation to arrive");

    while (!state1.joined || !state2.joined || !state3.joined) {

loop may never end

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auto_tests/simple_conference_test.c, line 190 at r1 (raw file):

    fprintf(stderr, "Waiting for messages to arrive");

    while (!state2.received || !state3.received) {

loop may never end

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Comments from Reviewable

[Diadlo]

@zoff99 Probably, it's right behaviour. Infinity loop will produce timeout error

[iphydf]

Correct. Infinite loops are intentional. CTest will kill the test if it times out.

[robinlinden]

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Reviewed 1 of 2 files at r1, 2 of 2 files at r2.
Review status: all files reviewed at latest revision, 4 unresolved discussions.

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Comments from Reviewable