1 files changed, 590 insertions, 0 deletions

diff --git a/quantum/sequencer/tests/sequencer_tests.cpp b/quantum/sequencer/tests/sequencer_tests.cpp
new file mode 100644
index 000000000..e81984e5b
--- /dev/null
+++ b/quantum/sequencer/tests/sequencer_tests.cpp
@@ -0,0 +1,590 @@
+/* Copyright 2020 Rodolphe Belouin
+ *
+ * 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.
+ *
+ * This program 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 General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gtest/gtest.h"
+
+extern "C" {
+#include "sequencer.h"
+#include "midi_mock.h"
+#include "quantum/quantum_keycodes.h"
+}
+
+extern "C" {
+void set_time(uint32_t t);
+void advance_time(uint32_t ms);
+}
+
+class SequencerTest : public ::testing::Test {
+   protected:
+    void SetUp() override {
+        config_copy.enabled = sequencer_config.enabled;
+
+        for (int i = 0; i < SEQUENCER_STEPS; i++) {
+            config_copy.steps[i] = sequencer_config.steps[i];
+        }
+
+        for (int i = 0; i < SEQUENCER_TRACKS; i++) {
+            config_copy.track_notes[i] = sequencer_config.track_notes[i];
+        }
+
+        config_copy.tempo      = sequencer_config.tempo;
+        config_copy.resolution = sequencer_config.resolution;
+
+        state_copy.active_tracks = sequencer_internal_state.active_tracks;
+        state_copy.current_track = sequencer_internal_state.current_track;
+        state_copy.current_step  = sequencer_internal_state.current_step;
+        state_copy.timer         = sequencer_internal_state.timer;
+
+        last_noteon  = 0;
+        last_noteoff = 0;
+
+        set_time(0);
+    }
+
+    void TearDown() override {
+        sequencer_config.enabled = config_copy.enabled;
+
+        for (int i = 0; i < SEQUENCER_STEPS; i++) {
+            sequencer_config.steps[i] = config_copy.steps[i];
+        }
+
+        for (int i = 0; i < SEQUENCER_TRACKS; i++) {
+            sequencer_config.track_notes[i] = config_copy.track_notes[i];
+        }
+
+        sequencer_config.tempo      = config_copy.tempo;
+        sequencer_config.resolution = config_copy.resolution;
+
+        sequencer_internal_state.active_tracks = state_copy.active_tracks;
+        sequencer_internal_state.current_track = state_copy.current_track;
+        sequencer_internal_state.current_step  = state_copy.current_step;
+        sequencer_internal_state.timer         = state_copy.timer;
+    }
+
+    sequencer_config_t config_copy;
+    sequencer_state_t  state_copy;
+};
+
+TEST_F(SequencerTest, TestOffByDefault) { EXPECT_EQ(is_sequencer_on(), false); }
+
+TEST_F(SequencerTest, TestOn) {
+    sequencer_config.enabled = false;
+
+    sequencer_on();
+    EXPECT_EQ(is_sequencer_on(), true);
+
+    // sequencer_on is idempotent
+    sequencer_on();
+    EXPECT_EQ(is_sequencer_on(), true);
+}
+
+TEST_F(SequencerTest, TestOff) {
+    sequencer_config.enabled = true;
+
+    sequencer_off();
+    EXPECT_EQ(is_sequencer_on(), false);
+
+    // sequencer_off is idempotent
+    sequencer_off();
+    EXPECT_EQ(is_sequencer_on(), false);
+}
+
+TEST_F(SequencerTest, TestToggle) {
+    sequencer_config.enabled = false;
+
+    sequencer_toggle();
+    EXPECT_EQ(is_sequencer_on(), true);
+
+    sequencer_toggle();
+    EXPECT_EQ(is_sequencer_on(), false);
+}
+
+TEST_F(SequencerTest, TestNoActiveTrackByDefault) {
+    for (int i = 0; i < SEQUENCER_TRACKS; i++) {
+        EXPECT_EQ(is_sequencer_track_active(i), false);
+    }
+}
+
+TEST_F(SequencerTest, TestGetActiveTracks) {
+    sequencer_internal_state.active_tracks = (1 << 7) + (1 << 6) + (1 << 3) + (1 << 1) + (1 << 0);
+
+    EXPECT_EQ(is_sequencer_track_active(0), true);
+    EXPECT_EQ(is_sequencer_track_active(1), true);
+    EXPECT_EQ(is_sequencer_track_active(2), false);
+    EXPECT_EQ(is_sequencer_track_active(3), true);
+    EXPECT_EQ(is_sequencer_track_active(4), false);
+    EXPECT_EQ(is_sequencer_track_active(5), false);
+    EXPECT_EQ(is_sequencer_track_active(6), true);
+    EXPECT_EQ(is_sequencer_track_active(7), true);
+}
+
+TEST_F(SequencerTest, TestGetActiveTracksOutOfBound) {
+    sequencer_set_track_activation(-1, true);
+    sequencer_set_track_activation(8, true);
+
+    EXPECT_EQ(is_sequencer_track_active(-1), false);
+    EXPECT_EQ(is_sequencer_track_active(8), false);
+}
+
+TEST_F(SequencerTest, TestToggleTrackActivation) {
+    sequencer_internal_state.active_tracks = (1 << 7) + (1 << 6) + (1 << 3) + (1 << 1) + (1 << 0);
+
+    sequencer_toggle_track_activation(6);
+
+    EXPECT_EQ(is_sequencer_track_active(0), true);
+    EXPECT_EQ(is_sequencer_track_active(1), true);
+    EXPECT_EQ(is_sequencer_track_active(2), false);
+    EXPECT_EQ(is_sequencer_track_active(3), true);
+    EXPECT_EQ(is_sequencer_track_active(4), false);
+    EXPECT_EQ(is_sequencer_track_active(5), false);
+    EXPECT_EQ(is_sequencer_track_active(6), false);
+    EXPECT_EQ(is_sequencer_track_active(7), true);
+}
+
+TEST_F(SequencerTest, TestToggleSingleTrackActivation) {
+    sequencer_internal_state.active_tracks = (1 << 7) + (1 << 6) + (1 << 3) + (1 << 1) + (1 << 0);
+
+    sequencer_toggle_single_active_track(2);
+
+    EXPECT_EQ(is_sequencer_track_active(0), false);
+    EXPECT_EQ(is_sequencer_track_active(1), false);
+    EXPECT_EQ(is_sequencer_track_active(2), true);
+    EXPECT_EQ(is_sequencer_track_active(3), false);
+    EXPECT_EQ(is_sequencer_track_active(4), false);
+    EXPECT_EQ(is_sequencer_track_active(5), false);
+    EXPECT_EQ(is_sequencer_track_active(6), false);
+    EXPECT_EQ(is_sequencer_track_active(7), false);
+}
+
+TEST_F(SequencerTest, TestStepOffByDefault) {
+    for (int i = 0; i < SEQUENCER_STEPS; i++) {
+        EXPECT_EQ(is_sequencer_step_on(i), false);
+    }
+}
+
+TEST_F(SequencerTest, TestIsStepOffWithNoActiveTracks) {
+    sequencer_config.steps[3] = 0xFF;
+    EXPECT_EQ(is_sequencer_step_on(3), false);
+}
+
+TEST_F(SequencerTest, TestIsStepOffWithGivenActiveTracks) {
+    sequencer_set_track_activation(2, true);
+    sequencer_set_track_activation(3, true);
+
+    sequencer_config.steps[3] = (1 << 0) + (1 << 1);
+
+    // No active tracks have the step enabled, so it is off
+    EXPECT_EQ(is_sequencer_step_on(3), false);
+}
+
+TEST_F(SequencerTest, TestIsStepOnWithGivenActiveTracks) {
+    sequencer_set_track_activation(2, true);
+    sequencer_set_track_activation(3, true);
+
+    sequencer_config.steps[3] = (1 << 2);
+
+    // Track 2 has the step enabled, so it is on
+    EXPECT_EQ(is_sequencer_step_on(3), true);
+}
+
+TEST_F(SequencerTest, TestIsStepOffForGivenTrack) {
+    sequencer_config.steps[3] = 0x00;
+    EXPECT_EQ(is_sequencer_step_on_for_track(3, 5), false);
+}
+
+TEST_F(SequencerTest, TestIsStepOnForGivenTrack) {
+    sequencer_config.steps[3] = (1 << 5);
+    EXPECT_EQ(is_sequencer_step_on_for_track(3, 5), true);
+}
+
+TEST_F(SequencerTest, TestSetStepOn) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = (1 << 5) + (1 << 2);
+
+    sequencer_set_step(2, true);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 6) + (1 << 5) + (1 << 3) + (1 << 2));
+}
+
+TEST_F(SequencerTest, TestSetStepOff) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = (1 << 5) + (1 << 2);
+
+    sequencer_set_step(2, false);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 5));
+}
+
+TEST_F(SequencerTest, TestToggleStepOff) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = (1 << 5) + (1 << 2);
+
+    sequencer_toggle_step(2);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 5));
+}
+
+TEST_F(SequencerTest, TestToggleStepOn) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = 0;
+
+    sequencer_toggle_step(2);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 6) + (1 << 3) + (1 << 2));
+}
+
+TEST_F(SequencerTest, TestSetAllStepsOn) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = (1 << 7) + (1 << 6);
+    sequencer_config.steps[4]              = (1 << 3) + (1 << 1);
+
+    sequencer_set_all_steps(true);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 7) + (1 << 6) + (1 << 3) + (1 << 2));
+    EXPECT_EQ(sequencer_config.steps[4], (1 << 6) + (1 << 3) + (1 << 2) + (1 << 1));
+}
+
+TEST_F(SequencerTest, TestSetAllStepsOff) {
+    sequencer_internal_state.active_tracks = (1 << 6) + (1 << 3) + (1 << 2);
+    sequencer_config.steps[2]              = (1 << 7) + (1 << 6);
+    sequencer_config.steps[4]              = (1 << 3) + (1 << 1);
+
+    sequencer_set_all_steps(false);
+
+    EXPECT_EQ(sequencer_config.steps[2], (1 << 7));
+    EXPECT_EQ(sequencer_config.steps[4], (1 << 1));
+}
+
+TEST_F(SequencerTest, TestSetTempoZero) {
+    sequencer_config.tempo = 123;
+
+    sequencer_set_tempo(0);
+
+    EXPECT_EQ(sequencer_config.tempo, 123);
+}
+
+TEST_F(SequencerTest, TestIncreaseTempoMax) {
+    sequencer_config.tempo = UINT8_MAX;
+
+    sequencer_increase_tempo();
+
+    EXPECT_EQ(sequencer_config.tempo, UINT8_MAX);
+}
+
+TEST_F(SequencerTest, TestSetResolutionLowerBound) {
+    sequencer_config.resolution = SQ_RES_4;
+
+    sequencer_set_resolution((sequencer_resolution_t)-1);
+
+    EXPECT_EQ(sequencer_config.resolution, SQ_RES_4);
+}
+
+TEST_F(SequencerTest, TestSetResolutionUpperBound) {
+    sequencer_config.resolution = SQ_RES_4;
+
+    sequencer_set_resolution(SEQUENCER_RESOLUTIONS);
+
+    EXPECT_EQ(sequencer_config.resolution, SQ_RES_4);
+}
+
+TEST_F(SequencerTest, TestGetBeatDuration) {
+    EXPECT_EQ(get_beat_duration(60), 1000);
+    EXPECT_EQ(get_beat_duration(120), 500);
+    EXPECT_EQ(get_beat_duration(240), 250);
+    EXPECT_EQ(get_beat_duration(0), 1000);
+}
+
+TEST_F(SequencerTest, TestGetStepDuration60) {
+    /**
+     * Resolution cheatsheet:
+     * 1/2  => 2 steps per 4 beats
+     * 1/2T => 3 steps per 4 beats
+     * 1/4  => 4 steps per 4 beats
+     * 1/4T => 6 steps per 4 beats
+     * 1/8  => 8 steps per 4 beats
+     * 1/8T => 12 steps per 4 beats
+     * 1/16 => 16 steps per 4 beats
+     * 1/16T => 24 steps per 4 beats
+     * 1/32 => 32 steps per 4 beats
+     *
+     * The number of steps for binary resolutions follows the powers of 2.
+     * The ternary variants are simply 1.5x faster.
+     */
+    EXPECT_EQ(get_step_duration(60, SQ_RES_2), 2000);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_4), 1000);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_8), 500);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_16), 250);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_32), 125);
+
+    EXPECT_EQ(get_step_duration(60, SQ_RES_2T), 1333);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_4T), 666);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_8T), 333);
+    EXPECT_EQ(get_step_duration(60, SQ_RES_16T), 166);
+}
+
+TEST_F(SequencerTest, TestGetStepDuration120) {
+    /**
+     * Resolution cheatsheet:
+     * 1/2  => 2 steps per 4 beats
+     * 1/2T => 3 steps per 4 beats
+     * 1/4  => 4 steps per 4 beats
+     * 1/4T => 6 steps per 4 beats
+     * 1/8  => 8 steps per 4 beats
+     * 1/8T => 12 steps per 4 beats
+     * 1/16 => 16 steps per 4 beats
+     * 1/16T => 24 steps per 4 beats
+     * 1/32 => 32 steps per 4 beats
+     *
+     * The number of steps for binary resolutions follows the powers of 2.
+     * The ternary variants are simply 1.5x faster.
+     */
+    EXPECT_EQ(get_step_duration(30, SQ_RES_2), 4000);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_4), 2000);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_8), 1000);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_16), 500);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_32), 250);
+
+    EXPECT_EQ(get_step_duration(30, SQ_RES_2T), 2666);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_4T), 1333);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_8T), 666);
+    EXPECT_EQ(get_step_duration(30, SQ_RES_16T), 333);
+}
+
+void setUpMatrixScanSequencerTest(void) {
+    sequencer_config.enabled    = true;
+    sequencer_config.tempo      = 120;
+    sequencer_config.resolution = SQ_RES_16;
+
+    // Configure the notes for each track
+    sequencer_config.track_notes[0] = MI_C;
+    sequencer_config.track_notes[1] = MI_D;
+    sequencer_config.track_notes[2] = MI_E;
+    sequencer_config.track_notes[3] = MI_F;
+    sequencer_config.track_notes[4] = MI_G;
+    sequencer_config.track_notes[5] = MI_A;
+    sequencer_config.track_notes[6] = MI_B;
+    sequencer_config.track_notes[7] = MI_C;
+
+    // Turn on some steps
+    sequencer_config.steps[0] = (1 << 0);
+    sequencer_config.steps[2] = (1 << 1) + (1 << 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldAttackFirstTrackOfFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, MI_C);
+    EXPECT_EQ(last_noteoff, 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldAttackSecondTrackAfterFirstTrackOfFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, 1);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_ATTACK);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldNotAttackInactiveTrackFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = 1;
+
+    // Wait some time after the first track has been attacked
+    advance_time(SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, 0);
+    EXPECT_EQ(last_noteoff, 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldAttackThirdTrackAfterSecondTrackOfFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = 1;
+
+    // Wait some time after the second track has been attacked
+    advance_time(2 * SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, 2);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_ATTACK);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldEnterReleasePhaseAfterLastTrackHasBeenProcessedFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = SEQUENCER_TRACKS - 1;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, 0);
+    EXPECT_EQ(last_noteoff, 0);
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, SEQUENCER_TRACKS - 1);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_RELEASE);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldReleaseBackwards) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = SEQUENCER_TRACKS - 1;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_RELEASE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, SEQUENCER_TRACKS - 2);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_RELEASE);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldNotReleaseInactiveTrackFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = SEQUENCER_TRACKS - 1;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_RELEASE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, 0);
+    EXPECT_EQ(last_noteoff, 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldReleaseFirstTrackFirstStep) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = 0;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_RELEASE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+    // + all the other notes have been released
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, 0);
+    EXPECT_EQ(last_noteoff, MI_C);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldEnterPausePhaseAfterRelease) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = 0;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_RELEASE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+    // + all the other notes have been released
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, 0);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_PAUSE);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldProcessFirstTrackOfSecondStepAfterPause) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.current_track = 0;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_PAUSE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+    // + all the other notes have been released
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the step duration (one 16th at tempo=120 lasts 125ms)
+    advance_time(125);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 1);
+    EXPECT_EQ(sequencer_internal_state.current_track, 1);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_ATTACK);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldProcessSecondTrackTooEarly) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 2;
+    sequencer_internal_state.current_track = 1;
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, 0);
+    EXPECT_EQ(last_noteoff, 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldProcessSecondTrackOnTime) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = 2;
+    sequencer_internal_state.current_track = 1;
+
+    // Wait until first track has been attacked
+    advance_time(SEQUENCER_TRACK_THROTTLE);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(last_noteon, MI_D);
+    EXPECT_EQ(last_noteoff, 0);
+}
+
+TEST_F(SequencerTest, TestMatrixScanSequencerShouldLoopOnceSequenceIsOver) {
+    setUpMatrixScanSequencerTest();
+
+    sequencer_internal_state.current_step  = SEQUENCER_STEPS - 1;
+    sequencer_internal_state.current_track = 0;
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_PAUSE;
+
+    // Wait until all notes have been attacked
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the release timeout
+    advance_time(SEQUENCER_PHASE_RELEASE_TIMEOUT);
+    // + all the other notes have been released
+    advance_time((SEQUENCER_TRACKS - 1) * SEQUENCER_TRACK_THROTTLE);
+    // + the step duration (one 16th at tempo=120 lasts 125ms)
+    advance_time(125);
+
+    matrix_scan_sequencer();
+    EXPECT_EQ(sequencer_internal_state.current_step, 0);
+    EXPECT_EQ(sequencer_internal_state.current_track, 1);
+    EXPECT_EQ(sequencer_internal_state.phase, SEQUENCER_PHASE_ATTACK);
+}