Add clock tests

The clock rolling sum is not trivial. Test it.

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',

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;
+};