1 files changed, 301 insertions, 0 deletions
diff --git a/ml/Tests.cc b/ml/Tests.cc
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index 000000000..7d369d48d
--- /dev/null
+++ b/ml/Tests.cc
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+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "BitBufferCounter.h"
+#include "BitRateWindow.h"
+
+#include "gtest/gtest.h"
+
+using namespace ml;
+
+TEST(BitBufferCounterTest, Cap_4) {
+    size_t Capacity = 4;
+    BitBufferCounter BBC(Capacity);
+
+    // No bits set
+    EXPECT_EQ(BBC.numSetBits(), 0);
+
+    // All ones
+    for (size_t Idx = 0; Idx != (2 * Capacity); Idx++) {
+        BBC.insert(true);
+
+        EXPECT_EQ(BBC.numSetBits(), std::min(Idx + 1, Capacity));
+    }
+
+    // All zeroes
+    for (size_t Idx = 0; Idx != Capacity; Idx++) {
+        BBC.insert(false);
+
+        if (Idx < Capacity)
+            EXPECT_EQ(BBC.numSetBits(), Capacity - (Idx + 1));
+        else
+            EXPECT_EQ(BBC.numSetBits(), 0);
+    }
+
+    // Even ones/zeroes
+    for (size_t Idx = 0; Idx != (2 * Capacity); Idx++)
+        BBC.insert(Idx % 2 == 0);
+    EXPECT_EQ(BBC.numSetBits(), Capacity / 2);
+}
+
+using State = BitRateWindow::State;
+using Edge = BitRateWindow::Edge;
+using Result = std::pair<Edge, size_t>;
+
+TEST(BitRateWindowTest, Cycles) {
+    /* Test the FSM by going through its two cycles:
+     *  1) NotFilled -> AboveThreshold -> Idle -> NotFilled
+     *  2) NotFilled -> BelowThreshold -> AboveThreshold -> Idle -> NotFilled
+     *
+     * Check the window's length on every new state transition.
+     */
+
+    size_t MinLength = 4, MaxLength = 6, IdleLength = 5;
+    size_t SetBitsThreshold = 3;
+
+    Result R;
+    BitRateWindow BRW(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    /*
+     * 1st cycle
+     */
+
+    // NotFilled -> AboveThreshold
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // AboveThreshold -> Idle
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::AboveThreshold));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::AboveThreshold));
+
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::Idle));
+    EXPECT_EQ(R.second, MaxLength);
+
+
+    // Idle -> NotFilled
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::NotFilled));
+    EXPECT_EQ(R.second, 1);
+
+    // NotFilled -> AboveThreshold
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    /*
+     * 2nd cycle
+     */
+
+    BRW = BitRateWindow(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    // NotFilled -> BelowThreshold
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::BelowThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // BelowThreshold -> BelowThreshold:
+    //      Check the state's self loop by adding set bits that will keep the
+    //      bit buffer below the specified threshold.
+    //
+    for (size_t Idx = 0; Idx != 2 * MaxLength; Idx++) {
+        R = BRW.insert(Idx % 2 == 0);
+        EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::BelowThreshold));
+        EXPECT_EQ(R.second, MinLength);
+    }
+
+    // Verify that at the end of the loop the internal bit buffer contains
+    // "1010". Do so by adding one set bit and checking that we remain below
+    // the specified threshold.
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::BelowThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // BelowThreshold -> AboveThreshold
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // AboveThreshold -> Idle:
+    //      Do the transition without filling the max window size this time.
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::Idle));
+    EXPECT_EQ(R.second, MinLength);
+
+    // Idle -> NotFilled
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::NotFilled));
+    EXPECT_EQ(R.second, 1);
+
+    // NotFilled -> AboveThreshold
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::NotFilled));
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+}
+
+TEST(BitRateWindowTest, ConsecutiveOnes) {
+    size_t MinLength = 120, MaxLength = 240, IdleLength = 30;
+    size_t SetBitsThreshold = 30;
+
+    Result R;
+    BitRateWindow BRW(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    for (size_t Idx = 0; Idx != MaxLength; Idx++)
+        R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::BelowThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    for (size_t Idx = 0; Idx != SetBitsThreshold; Idx++) {
+        EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::BelowThreshold));
+        R = BRW.insert(true);
+    }
+    EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // At this point the window's buffer contains:
+    //      (MinLength - SetBitsThreshold = 90) 0s, followed by
+    //                  (SetBitsThreshold = 30) 1s.
+    //
+    // To go below the threshold, we need to add (90 + 1) more 0s in the window's
+    // buffer. At that point, the the window's buffer will contain:
+    //                  (SetBitsThreshold = 29) 1s, followed by
+    //      (MinLength - SetBitsThreshold = 91) 0s.
+    //
+    // Right before adding the last 0, we expect the window's length to be equal to 210,
+    // because the bit buffer has gone through these bits:
+    //      (MinLength - SetBitsThreshold = 90) 0s, followed by
+    //                  (SetBitsThreshold = 30) 1s, followed by
+    //      (MinLength - SetBitsThreshold = 90) 0s.
+
+    for (size_t Idx = 0; Idx != (MinLength - SetBitsThreshold); Idx++) {
+        R = BRW.insert(false);
+        EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::AboveThreshold));
+    }
+    EXPECT_EQ(R.second, 2 * MinLength - SetBitsThreshold);
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::Idle));
+
+    // Continue with the Idle -> NotFilled edge.
+    for (size_t Idx = 0; Idx != IdleLength - 1; Idx++) {
+        R = BRW.insert(false);
+        EXPECT_EQ(R.first, std::make_pair(State::Idle, State::Idle));
+    }
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::Idle, State::NotFilled));
+    EXPECT_EQ(R.second, 1);
+}
+
+TEST(BitRateWindowTest, WithHoles) {
+    size_t MinLength = 120, MaxLength = 240, IdleLength = 30;
+    size_t SetBitsThreshold = 30;
+
+    Result R;
+    BitRateWindow BRW(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    for (size_t Idx = 0; Idx != MaxLength; Idx++)
+        R = BRW.insert(false);
+
+    for (size_t Idx = 0; Idx != SetBitsThreshold / 3; Idx++)
+        R = BRW.insert(true);
+    for (size_t Idx = 0; Idx != SetBitsThreshold / 3; Idx++)
+        R = BRW.insert(false);
+    for (size_t Idx = 0; Idx != SetBitsThreshold / 3; Idx++)
+        R = BRW.insert(true);
+    for (size_t Idx = 0; Idx != SetBitsThreshold / 3; Idx++)
+        R = BRW.insert(false);
+    for (size_t Idx = 0; Idx != SetBitsThreshold / 3; Idx++)
+        R = BRW.insert(true);
+
+    EXPECT_EQ(R.first, std::make_pair(State::BelowThreshold, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    // The window's bit buffer contains:
+    //      70 0s, 10 1s, 10 0s, 10 1s, 10 0s, 10 1s.
+    // Where: 70 = MinLength - (5 / 3) * SetBitsThresholds, ie. we need
+    // to add (70 + 1) more zeros to make the bit buffer go below the
+    // threshold and then the window's length should be:
+    //      70 + 50 + 70 = 190.
+
+    BitRateWindow::Edge E;
+    do {
+        R = BRW.insert(false);
+        E = R.first;
+    } while (E.first != State::AboveThreshold || E.second != State::Idle);
+    EXPECT_EQ(R.second, 2 * MinLength - (5 * SetBitsThreshold) / 3);
+}
+
+TEST(BitRateWindowTest, MinWindow) {
+    size_t MinLength = 120, MaxLength = 240, IdleLength = 30;
+    size_t SetBitsThreshold = 30;
+
+    Result R;
+    BitRateWindow BRW(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    BRW.insert(true);
+    BRW.insert(false);
+    for (size_t Idx = 2; Idx != SetBitsThreshold; Idx++)
+        BRW.insert(true);
+    for (size_t Idx = SetBitsThreshold; Idx != MinLength - 1; Idx++)
+        BRW.insert(false);
+
+    R = BRW.insert(true);
+    EXPECT_EQ(R.first, std::make_pair(State::NotFilled, State::AboveThreshold));
+    EXPECT_EQ(R.second, MinLength);
+
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::Idle));
+}
+
+TEST(BitRateWindowTest, MaxWindow) {
+    size_t MinLength = 100, MaxLength = 200, IdleLength = 30;
+    size_t SetBitsThreshold = 50;
+
+    Result R;
+    BitRateWindow BRW(MinLength, MaxLength, IdleLength, SetBitsThreshold);
+
+    for (size_t Idx = 0; Idx != MaxLength; Idx++)
+        R = BRW.insert(Idx % 2 == 0);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::AboveThreshold));
+    EXPECT_EQ(R.second, MaxLength);
+
+    R = BRW.insert(false);
+    EXPECT_EQ(R.first, std::make_pair(State::AboveThreshold, State::Idle));
+}