tests: internal: add peek/seek test for ring_buffer.

Signed-off-by: Phillip Adair Stewart Whelan <phillip.whelan@chronosphere.io>

Author: pwhelan

tests/internal/ring_buffer.c

@@ -161,6 +161,56 @@ static void test_smart_flush()
     flb_bucket_queue_destroy(bktq);
     mk_event_loop_destroy(evl);
 }
+
+void test_peek_seek()
+{
+    int i;
+    int ret;
+    int elements;
+    struct check *c;
+    struct check *tmp;
+    struct flb_ring_buffer *rb;
+
+    elements = sizeof(checks) / sizeof(struct check);
+
+    rb = flb_ring_buffer_create(sizeof(struct check *) * elements);
+    TEST_CHECK(rb != NULL);
+    if (!rb) {
+        exit(EXIT_FAILURE);
+    }
+
+    for (i = 0; i < elements; i++) {
+        c = &checks[i];
+        ret = flb_ring_buffer_write(rb, (void *) &c, sizeof(c));
+        TEST_CHECK(ret == 0);
+    }
+
+    /* try to write another record, it must fail */
+    tmp = c;
+    ret = flb_ring_buffer_write(rb, (void *) &tmp, sizeof(tmp));
+    TEST_CHECK(ret == -1);
+
+    c = NULL;
+
+    /* consume one entry */
+    ret = flb_ring_buffer_peek(rb, (void *) &c, sizeof(c));
+    TEST_CHECK(ret == 0);
+
+    /* the consumed entry must be equal to the first one */
+    c = &checks[0];
+    TEST_CHECK(strcmp(c->buf_a, "a1") == 0 && strcmp(c->buf_b, "a2") ==0);
+
+    /* consume one entry */
+    ret = flb_ring_buffer_peek(rb, (void *) &c, sizeof(c));
+    TEST_CHECK(ret == 0);
+
+    /* the consumed entry must be equal to the first one */
+    c = &checks[0];
+    TEST_CHECK(strcmp(c->buf_a, "a1") == 0 && strcmp(c->buf_b, "a2") ==0);
+
+    flb_ring_buffer_destroy(rb);
+}
+
 TEST_LIST = {
     { "basic",       test_basic},
     { "smart_flush", test_smart_flush},