tests: Factor out loopback setup code

This moves over setup code for the loopback latency test into a private
library so that we can easily write more tests using the same framework.

src/tests/lo-test-util.h

@@ -0,0 +1,57 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2013 Collabora Ltd.
+  Author: Arun Raghavan <arun.raghavan@collabora.co.uk>
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as published
+  by the Free Software Foundation; either version 2.1 of the License,
+  or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <pulse/pulseaudio.h>
+
+typedef struct pa_lo_test_context {
+    /* Tests need to set these */
+    const char *context_name;
+
+    pa_sample_spec sample_spec;
+    int play_latency; /* ms */
+    int rec_latency; /* ms */
+
+    pa_stream_request_cb_t write_cb, read_cb;
+
+    /* These are set by lo_test_init() */
+    pa_mainloop *mainloop;
+    pa_context *context;
+
+    pa_stream *play_stream, *rec_stream;
+
+    int ss, fs; /* sample size, frame size for convenience */
+} pa_lo_test_context;
+
+/* Initialise the test parameters, connect */
+int pa_lo_test_init(pa_lo_test_context *ctx);
+/* Start running the test */
+int pa_lo_test_run(pa_lo_test_context *ctx);
+/* Clean up */
+void pa_lo_test_deinit(pa_lo_test_context *ctx);
+
+/* Return RMS for the given signal. Assumes the data is a single channel for
+ * simplicity */
+float pa_rms(const float *s, int n);