From 2f03141e9fed348ae3053e1d185df3e1f8028e4a Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Tue, 6 Jul 2021 23:57:01 +0200
Subject: [PATCH] Add clock tests

The clock rolling sum is not trivial. Test it.
---
 app/meson.build        |  4 +++
 app/tests/test_clock.c | 79 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 app/tests/test_clock.c

diff --git a/app/meson.build b/app/meson.build
index d7ab0416..f5345803 100644
--- a/app/meson.build
+++ b/app/meson.build
@@ -168,6 +168,10 @@ if get_option('buildtype') == 'debug'
             'src/cli.c',
             'src/util/str_util.c',
         ]],
+        ['test_clock', [
+            'tests/test_clock.c',
+            'src/clock.c',
+        ]],
         ['test_control_msg_serialize', [
             'tests/test_control_msg_serialize.c',
             'src/control_msg.c',
diff --git a/app/tests/test_clock.c b/app/tests/test_clock.c
new file mode 100644
index 00000000..a88d5800
--- /dev/null
+++ b/app/tests/test_clock.c
@@ -0,0 +1,79 @@
+#include "common.h"
+
+#include <assert.h>
+
+#include "clock.h"
+
+void test_small_rolling_sum(void) {
+    struct sc_clock clock;
+    sc_clock_init(&clock);
+
+    assert(clock.count == 0);
+    assert(clock.left_sum.system == 0);
+    assert(clock.left_sum.stream == 0);
+    assert(clock.right_sum.system == 0);
+    assert(clock.right_sum.stream == 0);
+
+    sc_clock_update(&clock, 2, 3);
+    assert(clock.count == 1);
+    assert(clock.left_sum.system == 0);
+    assert(clock.left_sum.stream == 0);
+    assert(clock.right_sum.system == 2);
+    assert(clock.right_sum.stream == 3);
+
+    sc_clock_update(&clock, 10, 20);
+    assert(clock.count == 2);
+    assert(clock.left_sum.system == 2);
+    assert(clock.left_sum.stream == 3);
+    assert(clock.right_sum.system == 10);
+    assert(clock.right_sum.stream == 20);
+
+    sc_clock_update(&clock, 40, 80);
+    assert(clock.count == 3);
+    assert(clock.left_sum.system == 2);
+    assert(clock.left_sum.stream == 3);
+    assert(clock.right_sum.system == 50);
+    assert(clock.right_sum.stream == 100);
+
+    sc_clock_update(&clock, 400, 800);
+    assert(clock.count == 4);
+    assert(clock.left_sum.system == 12);
+    assert(clock.left_sum.stream == 23);
+    assert(clock.right_sum.system == 440);
+    assert(clock.right_sum.stream == 880);
+}
+
+void test_large_rolling_sum(void) {
+    const unsigned half_range = SC_CLOCK_RANGE / 2;
+
+    struct sc_clock clock1;
+    sc_clock_init(&clock1);
+    for (unsigned i = 0; i < 5 * half_range; ++i) {
+        sc_clock_update(&clock1, i, 2 * i + 1);
+    }
+
+    struct sc_clock clock2;
+    sc_clock_init(&clock2);
+    for (unsigned i = 3 * half_range; i < 5 * half_range; ++i) {
+        sc_clock_update(&clock2, i, 2 * i + 1);
+    }
+
+    assert(clock1.count == SC_CLOCK_RANGE);
+    assert(clock2.count == SC_CLOCK_RANGE);
+
+    // The values before the last SC_CLOCK_RANGE points in clock1 should have
+    // no impact
+    assert(clock1.left_sum.system == clock2.left_sum.system);
+    assert(clock1.left_sum.stream == clock2.left_sum.stream);
+    assert(clock1.right_sum.system == clock2.right_sum.system);
+    assert(clock1.right_sum.stream == clock2.right_sum.stream);
+}
+
+int main(int argc, char *argv[]) {
+    (void) argc;
+    (void) argv;
+
+    test_small_rolling_sum();
+    test_large_rolling_sum();
+    return 0;
+};