[WasmFS] Skip test_dlmalloc (#16139)

That test depends on the heap being in a pristine state so that we can predict
where allocations will happen. WasmFS apparently does enough malloc/free
during startup to disrupt that, and the test fails.

Also simplify the test code while I was debugging it.

Author: kripken

tests/dlmalloc_test.c

@@ -7,9 +7,9 @@
 
 // Emscripten tests
 
-#include <stdio.h>
-#include <stdlib.h>
 #include <assert.h>
+#include <emscripten.h>
+#include <stdlib.h>
 
 int main(int ac, char **av)
 {
@@ -20,67 +20,30 @@ int main(int ac, char **av)
     char* allocations[NUM];
     for (int i = 0; i < NUM/2; i++) {
       allocations[i] = (char*)malloc((11*i)%1024 + x);
-      //printf("zz alloc: %d\n", (int)allocations[i]);
       assert(allocations[i]);
       if (i > 10 && i%4 == 1 && allocations[i-10]) {
-        //printf("zz free: %d\n", (int)allocations[i-10]);
         free(allocations[i-10]);
         allocations[i-10] = NULL;
       }
     }
     for (int i = NUM/2; i < NUM; i++) {
       allocations[i] = (char*)malloc(1024*(i+1));
-      //printf("zz alloc: %d\n", (int)allocations[i]);
       assert(allocations[i]);
       if (i > 10 && i%4 != 1 && allocations[i-10]) {
-        //printf("zz free: %d\n", (int)allocations[i-10]);
         free(allocations[i-10]);
         allocations[i-10] = NULL;
       }
     }
     char* first = allocations[0];
     for (int i = 0; i < NUM; i++) {
       if (allocations[i]) {
-        //printf("zz free: %d\n", (int)allocations[i]);
         free(allocations[i]);
       }
     }
     char *last = (char*)malloc(512); // should be identical, as we free'd it all
-    //printf("zz last: %d\n", (int)last);
     char *newer = (char*)malloc(512); // should be different
-    //printf("zz newer: %d\n", (int)newer);
-#ifndef __APPLE__
     c1 += first == last;
     c2 += first == newer;
-#else // On OSX, it's been detected that memory is not necessarily allocated linearly, so skip this check and simulate success.
-    ++c1;
-#endif
   }
-  printf("*%d,%d*\n", c1, c2);
+  emscripten_log(EM_LOG_CONSOLE, "*%d,%d*\n", c1, c2);
 }
-
-/* Some debugging tools: Make JS and native code work exactly the same */
-/*
-time_t time ( time_t * timer )
-{
-  if (timer) *timer = 1;
-  return 1;
-}
-
-long sysconf(int name)
-{
-  printf("sysconf: %d (30 is page size)\n", name);
-  return 4096;
-}
-
-void *sbrk(intptr_t increment)
-{
-  static char spaace[1024*1024*1];
-  static intptr_t where = 0;
-  printf("sbrk! spaace=%d  (%d,%d)\n", (int)&spaace[0], where, increment); // copy the value printed at runtime here in native code into your js
-  void *ret = &spaace[where];
-  where += increment;
-  return ret;
-}
-*/
-

tests/test_core.py

@@ -304,6 +304,21 @@ def decorated(self, *args, **kwargs):
   return decorator
 
 
+def no_wasmfs(note):
+  assert not callable(note)
+
+  def decorator(f):
+    assert callable(f)
+
+    @wraps(f)
+    def decorated(self, *args, **kwargs):
+      if self.get_setting('WASMFS'):
+        self.skipTest(note)
+      f(self, *args, **kwargs)
+    return decorated
+  return decorator
+
+
 def make_no_decorator_for_setting(name):
   def outer_decorator(note):
     assert not callable(note)
@@ -5941,6 +5956,7 @@ def test_dlmalloc_inline(self):
   @require_v8
   @no_asan('depends on the specifics of memory size, which for asan we are forced to increase')
   @no_lsan('depends on the specifics of memory size, which for lsan we are forced to increase')
+  @no_wasmfs('wasmfs does some malloc/free during startup, fragmenting the heap, leading to differences later')
   def test_dlmalloc(self):
     # needed with typed arrays
     self.set_setting('INITIAL_MEMORY', '128mb')