Add a test for leaking memory in the C extension. Windows only for now, kind of experimental.

Author: nedbat

test/coveragetest.py

@@ -214,7 +214,7 @@ def check_coverage(self, text, lines=None, missing="", excludes=None,
             cov.report(mod, file=frep)
             rep = " ".join(frep.getvalue().split("\n")[2].split()[1:])
             self.assertEqual(report, rep)
-
+        
     def assert_raises_msg(self, excClass, msg, callableObj, *args, **kwargs):
         """ Just like unittest.TestCase.assertRaises,
             but checks that the message is right too.

test/osinfo.py

@@ -0,0 +1,40 @@
+"""OS information for testing."""
+
+import sys
+
+if sys.hexversion >= 0x02050000 and sys.platform == 'win32':
+    # Windows implementation
+    def process_ram():
+        """How much RAM is this process using? (Windows)"""
+        import ctypes
+        # lifted from:
+        # lists.ubuntu.com/archives/bazaar-commits/2009-February/011990.html
+        class PROCESS_MEMORY_COUNTERS_EX(ctypes.Structure):
+            """Used by GetProcessMemoryInfo"""
+            _fields_ = [('cb', ctypes.c_ulong),
+                        ('PageFaultCount', ctypes.c_ulong),
+                        ('PeakWorkingSetSize', ctypes.c_size_t),
+                        ('WorkingSetSize', ctypes.c_size_t),
+                        ('QuotaPeakPagedPoolUsage', ctypes.c_size_t),
+                        ('QuotaPagedPoolUsage', ctypes.c_size_t),
+                        ('QuotaPeakNonPagedPoolUsage', ctypes.c_size_t),
+                        ('QuotaNonPagedPoolUsage', ctypes.c_size_t),
+                        ('PagefileUsage', ctypes.c_size_t),
+                        ('PeakPagefileUsage', ctypes.c_size_t),
+                        ('PrivateUsage', ctypes.c_size_t),
+                       ]
+    
+        mem_struct = PROCESS_MEMORY_COUNTERS_EX()
+        ret = ctypes.windll.psapi.GetProcessMemoryInfo(
+                    ctypes.windll.kernel32.GetCurrentProcess(),
+                    ctypes.byref(mem_struct),
+                    ctypes.sizeof(mem_struct)
+                    )
+        if not ret:
+            return 0
+        return mem_struct.PrivateUsage
+
+else:
+    def process_ram():
+        """How much RAM is this process using? (no implementation)"""
+        return 0

test/test_coverage.py

@@ -9,6 +9,7 @@
 
 sys.path.insert(0, os.path.split(__file__)[0]) # Force relative import for Py3k
 from coveragetest import CoverageTest
+import osinfo
 
 
 class BasicCoverageTest(CoverageTest):
@@ -1730,6 +1731,36 @@ def recur(n):
             [1,2,3,5,7], "")
 
 
+class MemoryLeakTest(CoverageTest):
+    """Attempt the impossible: test that memory doesn't leak."""
+
+    def test_for_leaks(self):
+        lines = list(range(301, 315))
+        lines.remove(306)
+        baseline_ram = osinfo.process_ram()
+        # Ugly string mumbo jumbo to get 300 blank lines at the beginning..
+        self.check_coverage("""\
+            # blank line\n""" * 300 + """\
+            def once(x):
+                if x % 100 == 0:
+                    raise Exception("100!")
+                elif x % 2:
+                    return 10
+                else:
+                    return 11
+            i = 0 # Portable loop without alloc'ing memory.
+            while i < 10000:
+                try:
+                    once(i)
+                except:
+                    pass
+                i += 1
+            """,
+            lines, "")
+        ram_growth = osinfo.process_ram() - baseline_ram
+        self.assert_(ram_growth < 100000, "RAM grew by %d" % (ram_growth))
+
+
 class PyexpatTest(CoverageTest):
     """Pyexpat screws up tracing. Make sure we've counter-defended properly."""