Add a more representative test for the snapshot.

tests/test-msnapshot.c

@@ -23,6 +23,7 @@
 #include <gmp.h> // For testing purpose only.
 
 #include "m-snapshot.h"
+#include "m-mutex.h"
 
 #include "coverage.h"
 START_COVERAGE
@@ -74,9 +75,72 @@ static void test_uint(void)
   assert (*snapshot_uint_look(t) == 3);
 }
 
+typedef struct {
+  unsigned int n;
+  unsigned int c;
+  unsigned int p;
+} data_t;
+
+static void data_crc(data_t *p) { p->p = -p->n; p->c = ~p->n; }
+static void data_init(data_t *p) { p->n = 0; data_crc(p); }
+static void data_clear(data_t *p) { (void) p;}
+static void data_set(data_t *p, data_t o) { p->p = o.p; data_crc(p); }
+
+SNAPSHOT_DEF(snapshot_data, data_t,
+             (INIT(data_init M_IPTR), INIT_SET(data_set M_IPTR), SET(data_set M_IPTR), CLEAR(data_clear M_IPTR))
+             )
+
+snapshot_data_t g_buff;
+
+static void conso(void *arg)
+{
+  assert (arg == NULL);
+  while (true) {
+    const data_t *p = snapshot_data_look(g_buff);
+    assert (p->n == -p->p);
+    assert (p->n == ~p->c);
+    if (p->n == 0)
+      return;
+  }
+}
+
+static void prod(void *arg)
+{
+  assert (arg == NULL);
+  data_t *p = snapshot_data_get_write_buffer(g_buff);
+  for(unsigned int i = 1; i < 100000;i++) {
+    p->n = i * i;
+    data_crc(p);
+    p = snapshot_data_take(g_buff);
+  }
+  p->n = 0;
+  data_crc(p);
+  p = snapshot_data_take(g_buff);
+}
+
+static void test_global(void)
+{
+  m_thread_t idx[2];
+
+  snapshot_data_init(g_buff);
+  data_t *p = snapshot_data_take(g_buff);
+  p->n = 42;
+  data_crc(p);
+  p = snapshot_data_take(g_buff);
+
+  m_thread_create (idx[0], conso, NULL);
+  m_thread_create (idx[1], prod, NULL);
+
+  m_thread_join(idx[0]);
+  m_thread_join(idx[1]);
+
+  snapshot_data_clear(g_buff);
+}
+
 int main(void)
 {
   test_uint();
+  test_global();
   exit(0);
 }