diff --git a/Lib/test/test_bz2.py b/Lib/test/test_bz2.py
index d9ccf0a..72aea1b 100644
--- a/Lib/test/test_bz2.py
+++ b/Lib/test/test_bz2.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 from test import test_support
-from test.test_support import TESTFN, import_module
+from test.test_support import TESTFN, _4G, bigmemtest, import_module, findfile
 
 import unittest
 from cStringIO import StringIO
@@ -24,6 +24,9 @@
     DATA = 'BZh91AY&SY.\xc8N\x18\x00\x01>_\x80\x00\x10@\x02\xff\xf0\x01\x07n\x00?\xe7\xff\xe00\x01\x99\xaa\x00\xc0\x03F\x86\x8c#&\x83F\x9a\x03\x06\xa6\xd0\xa6\x93M\x0fQ\xa7\xa8\x06\x804hh\x12$\x11\xa4i4\xf14S\xd2<Q\xb5\x0fH\xd3\xd4\xdd\xd5\x87\xbb\xf8\x94\r\x8f\xafI\x12\xe1\xc9\xf8/E\x00pu\x89\x12]\xc9\xbbDL\nQ\x0e\t1\x12\xdf\xa0\xc0\x97\xac2O9\x89\x13\x94\x0e\x1c7\x0ed\x95I\x0c\xaaJ\xa4\x18L\x10\x05#\x9c\xaf\xba\xbc/\x97\x8a#C\xc8\xe1\x8cW\xf9\xe2\xd0\xd6M\xa7\x8bXa<e\x84t\xcbL\xb3\xa7\xd9\xcd\xd1\xcb\x84.\xaf\xb3\xab\xab\xad`n}\xa0lh\tE,\x8eZ\x15\x17VH>\x88\xe5\xcd9gd6\x0b\n\xe9\x9b\xd5\x8a\x99\xf7\x08.K\x8ev\xfb\xf7xw\xbb\xdf\xa1\x92\xf1\xdd|/";\xa2\xba\x9f\xd5\xb1#A\xb6\xf6\xb3o\xc9\xc5y\\\xebO\xe7\x85\x9a\xbc\xb6f8\x952\xd5\xd7"%\x89>V,\xf7\xa6z\xe2\x9f\xa3\xdf\x11\x11"\xd6E)I\xa9\x13^\xca\xf3r\xd0\x03U\x922\xf26\xec\xb6\xed\x8b\xc3U\x13\x9d\xc5\x170\xa4\xfa^\x92\xacDF\x8a\x97\xd6\x19\xfe\xdd\xb8\xbd\x1a\x9a\x19\xa3\x80ankR\x8b\xe5\xd83]\xa9\xc6\x08\x82f\xf6\xb9"6l$\xb8j@\xc0\x8a\xb0l1..\xbak\x83ls\x15\xbc\xf4\xc1\x13\xbe\xf8E\xb8\x9d\r\xa8\x9dk\x84\xd3n\xfa\xacQ\x07\xb1%y\xaav\xb4\x08\xe0z\x1b\x16\xf5\x04\xe9\xcc\xb9\x08z\x1en7.G\xfc]\xc9\x14\xe1B@\xbb!8`'
     DATA_CRLF = 'BZh91AY&SY\xaez\xbbN\x00\x01H\xdf\x80\x00\x12@\x02\xff\xf0\x01\x07n\x00?\xe7\xff\xe0@\x01\xbc\xc6`\x86*\x8d=M\xa9\x9a\x86\xd0L@\x0fI\xa6!\xa1\x13\xc8\x88jdi\x8d@\x03@\x1a\x1a\x0c\x0c\x83 \x00\xc4h2\x19\x01\x82D\x84e\t\xe8\x99\x89\x19\x1ah\x00\r\x1a\x11\xaf\x9b\x0fG\xf5(\x1b\x1f?\t\x12\xcf\xb5\xfc\x95E\x00ps\x89\x12^\xa4\xdd\xa2&\x05(\x87\x04\x98\x89u\xe40%\xb6\x19\'\x8c\xc4\x89\xca\x07\x0e\x1b!\x91UIFU%C\x994!DI\xd2\xfa\xf0\xf1N8W\xde\x13A\xf5\x9cr%?\x9f3;I45A\xd1\x8bT\xb1<l\xba\xcb_\xc00xY\x17r\x17\x88\x08\x08@\xa0\ry@\x10\x04$)`\xf2\xce\x89z\xb0s\xec\x9b.iW\x9d\x81\xb5-+t\x9f\x1a\'\x97dB\xf5x\xb5\xbe.[.\xd7\x0e\x81\xe7\x08\x1cN`\x88\x10\xca\x87\xc3!"\x80\x92R\xa1/\xd1\xc0\xe6mf\xac\xbd\x99\xcca\xb3\x8780>\xa4\xc7\x8d\x1a\\"\xad\xa1\xabyBg\x15\xb9l\x88\x88\x91k"\x94\xa4\xd4\x89\xae*\xa6\x0b\x10\x0c\xd6\xd4m\xe86\xec\xb5j\x8a\x86j\';\xca.\x01I\xf2\xaaJ\xe8\x88\x8cU+t3\xfb\x0c\n\xa33\x13r2\r\x16\xe0\xb3(\xbf\x1d\x83r\xe7M\xf0D\x1365\xd8\x88\xd3\xa4\x92\xcb2\x06\x04\\\xc1\xb0\xea//\xbek&\xd8\xe6+t\xe5\xa1\x13\xada\x16\xder5"w]\xa2i\xb7[\x97R \xe2IT\xcd;Z\x04dk4\xad\x8a\t\xd3\x81z\x10\xf1:^`\xab\x1f\xc5\xdc\x91N\x14$+\x9e\xae\xd3\x80'
 
+    with open(findfile("testbz2_bigmem.bz2"), "rb") as f:
+        DATA_BIGMEM = f.read()
+
     if has_cmdline_bunzip2:
         def decompress(self, data):
             pop = subprocess.Popen("bunzip2", shell=True,
@@ -43,6 +46,7 @@
         def decompress(self, data):
             return bz2.decompress(data)
 
+
 class BZ2FileTest(BaseTest):
     "Test BZ2File type miscellaneous methods."
 
@@ -346,6 +350,17 @@
         data += bz2c.flush()
         self.assertEqual(self.decompress(data), self.TEXT)
 
+    @bigmemtest(_4G, memuse=1.25)
+    def testBigmem(self, size):
+        text = "a" * size
+        bz2c = bz2.BZ2Compressor()
+        data = bz2c.compress(text) + bz2c.flush()
+        del text
+        text = self.decompress(data)
+        self.assertEqual(len(text), size)
+        self.assertEqual(text.strip("a"), "")
+
+
 class BZ2DecompressorTest(BaseTest):
     def test_Constructor(self):
         self.assertRaises(TypeError, BZ2Decompressor, 42)
@@ -384,6 +399,15 @@
         text = bz2d.decompress(self.DATA)
         self.assertRaises(EOFError, bz2d.decompress, "anything")
 
+    @bigmemtest(_4G, memuse=1.25)
+    def testBigmem(self, size):
+        # Issue #14398: decompression fails when output data is >=2GB.
+        if size < _4G:
+            self.skipTest("Test needs 5GB of memory to run.")
+        text = bz2.BZ2Decompressor().decompress(self.DATA_BIGMEM)
+        self.assertEqual(len(text), _4G)
+        self.assertEqual(text.strip("\0"), "")
+
 
 class FuncTest(BaseTest):
     "Test module functions"
@@ -407,6 +431,24 @@
         # "Test decompress() function with incomplete data"
         self.assertRaises(ValueError, bz2.decompress, self.DATA[:-10])
 
+    @bigmemtest(_4G, memuse=1.25)
+    def testCompressBigmem(self, size):
+        text = "a" * size
+        data = bz2.compress(text)
+        del text
+        text = self.decompress(data)
+        self.assertEqual(len(text), size)
+        self.assertEqual(text.strip("a"), "")
+
+    @bigmemtest(_4G, memuse=1.25)
+    def testDecompressBigmem(self, size):
+        # Issue #14398: decompression fails when output data is >=2GB.
+        if size < _4G:
+            self.skipTest("Test needs 5GB of memory to run.")
+        text = bz2.decompress(self.DATA_BIGMEM)
+        self.assertEqual(len(text), _4G)
+        self.assertEqual(text.strip("\0"), "")
+
 def test_main():
     test_support.run_unittest(
         BZ2FileTest,
diff --git a/Lib/test/testbz2_bigmem.bz2 b/Lib/test/testbz2_bigmem.bz2
new file mode 100644
index 0000000..c9a4616
--- /dev/null
+++ b/Lib/test/testbz2_bigmem.bz2
Binary files differ