Initial simple test

meson.build

@@ -93,6 +93,7 @@ unit_test_sources = [
   'src/test/TestVectorOps.cpp',
   'src/test/TestSignalBits.cpp',
   'src/test/TestStretchCalculator.cpp',
+  'src/test/TestStretcher.cpp',
   'src/test/TestBinClassifier.cpp',
   'src/test/test.cpp',
 ]

src/test/TestStretcher.cpp

@@ -0,0 +1,88 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Rubber Band Library
+    An audio time-stretching and pitch-shifting library.
+    Copyright 2007-2022 Particular Programs Ltd.
+
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+
+    Alternatively, if you have a valid commercial licence for the
+    Rubber Band Library obtained by agreement with the copyright
+    holders, you may redistribute and/or modify it under the terms
+    described in that licence.
+
+    If you wish to distribute code using the Rubber Band Library
+    under terms other than those of the GNU General Public License,
+    you must obtain a valid commercial licence before doing so.
+*/
+
+#define BOOST_TEST_DYN_LINK
+#include <boost/test/unit_test.hpp>
+
+#include "../../rubberband/RubberBandStretcher.h"
+
+#include <iostream>
+
+#include <cmath>
+
+using namespace RubberBand;
+using namespace std;
+namespace tt = boost::test_tools;
+
+BOOST_AUTO_TEST_SUITE(TestStretcher)
+
+BOOST_AUTO_TEST_CASE(sinusoid_unchanged_single_offline)
+{
+    int n = 10000;
+    float freq = 440.f;
+    int rate = 44100;
+    RubberBandStretcher stretcher(rate, 1);
+    vector<float> in(n), out(n);
+    for (int i = 0; i < n; ++i) {
+        in[i] = sinf(float(i) * freq * M_PI * 2.f / float(rate));
+    }
+    float *inp = in.data(), *outp = out.data();
+
+    stretcher.setMaxProcessSize(n);
+    stretcher.setExpectedInputDuration(n);
+    BOOST_TEST(stretcher.available() == 0);
+
+    stretcher.study(&inp, n, true);
+    BOOST_TEST(stretcher.available() == 0);
+
+    stretcher.process(&inp, n, true);
+    BOOST_TEST(stretcher.available() == n);
+
+    size_t got = stretcher.retrieve(&outp, n);
+    BOOST_TEST(got == n);
+    BOOST_TEST(stretcher.available() == -1);
+
+    // We now have n samples of a simple sinusoid with stretch factor
+    // 1.0; obviously we expect the output to be essentially the same
+    // thing. It will have lower precision for a while at the start
+    // and end because of windowing factors, so we check those with a
+    // threshold of 0.1; in the middle we expect better precision.
+
+    // This syntax for comparing containers with a certain tolerance
+    // using BOOST_TEST is just bonkers. I can't find the << syntax to
+    // combine manipulators documented anywhere other than in a
+    // release note, but it does work. Well, sort of - it works this
+    // way around but not as per_element << tolerance. And
+    // tolerance(0.1) doesn't do what you'd expect if the things
+    // you're comparing are floats (it sets the tolerance for doubles,
+    // leaving float comparison unchanged). Clever... too clever.
+    
+    BOOST_TEST(in == out,
+               tt::tolerance(0.1f) << tt::per_element());
+    
+    BOOST_TEST(vector<float>(in.begin() + 1000, in.begin() + n - 1000) ==
+               vector<float>(out.begin() + 1000, out.begin() + n - 1000),
+               tt::tolerance(0.0001f) << tt::per_element());
+}
+
+BOOST_AUTO_TEST_SUITE_END()