ipa/test: Add test program for IPA message reception

This patch adds tests for ipa_msg_recv(), where messages are sent
either complete or partitioned.

Sponsored-by: On-Waves ehf
diff --git a/tests/ipa_recv/ipa_recv_test.ok b/tests/ipa_recv/ipa_recv_test.ok
new file mode 100644
index 0000000..4144d47
--- /dev/null
+++ b/tests/ipa_recv/ipa_recv_test.ok
@@ -0,0 +1,12 @@
+Testing the IPA layer.
+Testing IPA recv with complete messages.
+got IPA message, size=10, proto=200, text="Hello IPA"
+got IPA message, size=86, proto=200, text="A longer test message. ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz"
+got IPA message, size=16, proto=200, text="Hello again IPA"
+got IPA message, size=1, proto=200, text=""
+got IPA message, size=14, proto=200, text="Next is empty"
+done: unread 14, unsent 0
+Testing IPA recv with partitioned messages.
+ipa_msg_recv failed with: Input/output error
+done: unread 0, unsent 154
+No crashes.