Implemented rate limiter.

Fixes #12.

1 files changed, 68 insertions, 0 deletions

diff --git a/tests/internals/test_rate_limiter.c b/tests/internals/test_rate_limiter.c
new file mode 100644
index 0000000..93cdda5
--- /dev/null
+++ b/tests/internals/test_rate_limiter.c
@@ -0,0 +1,68 @@
+
+#include "test_common.h"
+#include "rate_limiter.h"
+
+static const double epsilon = 0.000000000001;
+
+static volatile double time_now = 123123.0;
+
+double test_clock()
+{
+    return time_now;
+}
+
+void computes_correct_sleep_times()
+{
+    time_now = 123123.0;
+    RateLimiter limiter;
+    rate_limiter_init(&limiter, 10, &test_clock);
+
+    double sleep_time = rate_limiter_wait_nosleep(&limiter, 30);
+    TEST_ASSERT(NEAR(3.0 + rate_limiter_idle_credit, sleep_time, epsilon));
+    sleep_time = rate_limiter_wait_nosleep(&limiter, 20);
+    TEST_ASSERT(NEAR(5.0 + rate_limiter_idle_credit, sleep_time, epsilon));
+
+    time_now += 0.5;
+    sleep_time = rate_limiter_wait_nosleep(&limiter, 30);
+    TEST_ASSERT(NEAR(7.5 + rate_limiter_idle_credit, sleep_time, epsilon));
+
+    rate_limiter_destroy(&limiter);
+}
+
+void works_after_being_idle()
+{
+    time_now = 123123.0;
+    RateLimiter limiter;
+    rate_limiter_init(&limiter, 10, &test_clock);
+
+    double sleep_time = rate_limiter_wait_nosleep(&limiter, 30);
+    TEST_ASSERT(NEAR(3.0 + rate_limiter_idle_credit, sleep_time, epsilon));
+    time_now += 100;
+
+    sleep_time = rate_limiter_wait_nosleep(&limiter, 20);
+    TEST_ASSERT(NEAR(2 + rate_limiter_idle_credit, sleep_time, epsilon));
+
+    rate_limiter_destroy(&limiter);
+}
+
+void sleeps_correct_amount()
+{
+    RateLimiter limiter;
+    rate_limiter_init(&limiter, 10, &gettimeofday_clock);
+
+    double start = gettimeofday_clock();
+    rate_limiter_wait(&limiter, 5);
+    double elapsed = gettimeofday_clock() - start;
+    TEST_ASSERT(NEAR(0.5, elapsed, 0.2));
+
+    rate_limiter_destroy(&limiter);
+}
+
+void rate_limiter_suite()
+{
+    computes_correct_sleep_times();
+    works_after_being_idle();
+    sleeps_correct_amount();
+}
+
+TEST_MAIN(rate_limiter_suite);