tests: Fix a flaky test

This test was treating every `free()` for the same address as though it
was freeing a block of memory we care about, instead of only the first
`free()` for that address after it was allocated.

Fix this by only paying attention to the first free found for an address
after it was allocated by an allocator we're interested in.

Authored-by: Matt Wozniski <mwozniski@bloomberg.net>
Reviewed-by: Pablo Galindo <pgalindo3@bloomberg.net>
Signed-off-by: Matt Wozniski <mwozniski@bloomberg.net>

tests/integration/test_native_tracking.py

@@ -41,9 +41,18 @@ def test_multithreaded_extension_with_native_tracking(tmpdir, monkeypatch):
 
     # THEN
     records = list(FileReader(output).get_allocation_records())
-    memaligns = [
-        record for record in records if record.allocator == AllocatorType.MEMALIGN
-    ]
+    memaligns = []
+    memalign_frees = []
+    outstanding_memaligns = set()
+
+    for record in records:
+        if record.allocator == AllocatorType.MEMALIGN:
+            memaligns.append(record)
+            outstanding_memaligns.add(record.address)
+        elif record.allocator == AllocatorType.FREE:
+            if record.address in outstanding_memaligns:
+                outstanding_memaligns.remove(record.address)
+                memalign_frees.append(record)
 
     assert len(memaligns) == 100 * 100  # 100 threads allocate 100 times in testext
     assert all(len(memalign.stack_trace()) == 0 for memalign in memaligns)
@@ -53,14 +62,7 @@ def test_multithreaded_extension_with_native_tracking(tmpdir, monkeypatch):
         for record in memaligns
     )
 
-    memaligns_addr = {record.address for record in memaligns}
-    memalign_frees = [
-        record
-        for record in records
-        if record.address in memaligns_addr and record.allocator == AllocatorType.FREE
-    ]
-
-    assert len(memalign_frees) >= 100 * 100
+    assert len(memalign_frees) == 100 * 100
     assert all(len(memalign.stack_trace()) == 0 for memalign in memalign_frees)
     assert all(len(record.native_stack_trace()) == 0 for record in memalign_frees)