Some new blood and some updated versions.
diff --git a/Lib/dos-8x3/test_lon.py b/Lib/dos-8x3/test_lon.py
new file mode 100644
index 0000000..f235d9c
--- /dev/null
+++ b/Lib/dos-8x3/test_lon.py
@@ -0,0 +1,252 @@
+from test_support import TestFailed, verbose
+from string import join
+from random import random, randint
+
+# SHIFT should match the value in longintrepr.h for best testing.
+SHIFT = 15
+BASE = 2 ** SHIFT
+MASK = BASE - 1
+
+# Max number of base BASE digits to use in test cases.  Doubling
+# this will at least quadruple the runtime.
+MAXDIGITS = 10
+
+# build some special values
+special = map(long, [0, 1, 2, BASE, BASE >> 1])
+special.append(0x5555555555555555L)
+special.append(0xaaaaaaaaaaaaaaaaL)
+#  some solid strings of one bits
+p2 = 4L  # 0 and 1 already added
+for i in range(2*SHIFT):
+    special.append(p2 - 1)
+    p2 = p2 << 1
+del p2
+# add complements & negations
+special = special + map(lambda x: ~x, special) + \
+                    map(lambda x: -x, special)
+
+# ------------------------------------------------------------ utilities
+
+# Use check instead of assert so the test still does something
+# under -O.
+
+def check(ok, *args):
+    if not ok:
+        raise TestFailed, join(map(str, args), " ")
+
+# Get quasi-random long consisting of ndigits digits (in base BASE).
+# quasi == the most-significant digit will not be 0, and the number
+# is constructed to contain long strings of 0 and 1 bits.  These are
+# more likely than random bits to provoke digit-boundary errors.
+# The sign of the number is also random.
+
+def getran(ndigits):
+    assert ndigits > 0
+    nbits_hi = ndigits * SHIFT
+    nbits_lo = nbits_hi - SHIFT + 1
+    answer = 0L
+    nbits = 0
+    r = int(random() * (SHIFT * 2)) | 1  # force 1 bits to start
+    while nbits < nbits_lo:
+        bits = (r >> 1) + 1
+        bits = min(bits, nbits_hi - nbits)
+        assert 1 <= bits <= SHIFT
+        nbits = nbits + bits
+        answer = answer << bits
+        if r & 1:
+            answer = answer | ((1 << bits) - 1)
+        r = int(random() * (SHIFT * 2))
+    assert nbits_lo <= nbits <= nbits_hi
+    if random() < 0.5:
+        answer = -answer
+    return answer
+
+# Get random long consisting of ndigits random digits (relative to base
+# BASE).  The sign bit is also random.
+
+def getran2(ndigits):
+    answer = 0L
+    for i in range(ndigits):
+        answer = (answer << SHIFT) | randint(0, MASK)
+    if random() < 0.5:
+        answer = -answer
+    return answer
+
+# --------------------------------------------------------------- divmod
+
+def test_division_2(x, y):
+    q, r = divmod(x, y)
+    q2, r2 = x/y, x%y
+    check(q == q2, "divmod returns different quotient than / for", x, y)
+    check(r == r2, "divmod returns different mod than % for", x, y)
+    check(x == q*y + r, "x != q*y + r after divmod on", x, y)
+    if y > 0:
+        check(0 <= r < y, "bad mod from divmod on", x, y)
+    else:
+        check(y < r <= 0, "bad mod from divmod on", x, y)
+
+def test_division(maxdigits=MAXDIGITS):
+    print "long / * % divmod"
+    digits = range(1, maxdigits+1)
+    for lenx in digits:
+        x = getran(lenx)
+        for leny in digits:
+            y = getran(leny) or 1L
+            test_division_2(x, y)
+
+# -------------------------------------------------------------- ~ & | ^
+
+def test_bitop_identities_1(x):
+    check(x & 0 == 0, "x & 0 != 0 for", x)
+    check(x | 0 == x, "x | 0 != x for", x)
+    check(x ^ 0 == x, "x ^ 0 != x for", x)
+    check(x & -1 == x, "x & -1 != x for", x)
+    check(x | -1 == -1, "x | -1 != -1 for", x)
+    check(x ^ -1 == ~x, "x ^ -1 != ~x for", x)
+    check(x == ~~x, "x != ~~x for", x)
+    check(x & x == x, "x & x != x for", x)
+    check(x | x == x, "x | x != x for", x)
+    check(x ^ x == 0, "x ^ x != 0 for", x)
+    check(x & ~x == 0, "x & ~x != 0 for", x)
+    check(x | ~x == -1, "x | ~x != -1 for", x)
+    check(x ^ ~x == -1, "x ^ ~x != -1 for", x)
+    check(-x == 1 + ~x == ~(x-1), "not -x == 1 + ~x == ~(x-1) for", x)
+    for n in range(2*SHIFT):
+        p2 = 2L ** n
+        check(x << n >> n == x, "x << n >> n != x for", x, n)
+        check(x / p2 == x >> n, "x / p2 != x >> n for x n p2", x, n, p2)
+        check(x * p2 == x << n, "x * p2 != x << n for x n p2", x, n, p2)
+        check(x & -p2 == x >> n << n == x & ~(p2 - 1),
+            "not x & -p2 == x >> n << n == x & ~(p2 - 1) for x n p2",
+            x, n, p2)
+
+def test_bitop_identities_2(x, y):
+    check(x & y == y & x, "x & y != y & x for", x, y)
+    check(x | y == y | x, "x | y != y | x for", x, y)
+    check(x ^ y == y ^ x, "x ^ y != y ^ x for", x, y)
+    check(x ^ y ^ x == y, "x ^ y ^ x != y for", x, y)
+    check(x & y == ~(~x | ~y), "x & y != ~(~x | ~y) for", x, y)
+    check(x | y == ~(~x & ~y), "x | y != ~(~x & ~y) for", x, y)
+    check(x ^ y == (x | y) & ~(x & y),
+         "x ^ y != (x | y) & ~(x & y) for", x, y)
+    check(x ^ y == (x & ~y) | (~x & y),
+         "x ^ y == (x & ~y) | (~x & y) for", x, y)
+    check(x ^ y == (x | y) & (~x | ~y),
+         "x ^ y == (x | y) & (~x | ~y) for", x, y)
+
+def test_bitop_identities_3(x, y, z):
+    check((x & y) & z == x & (y & z),
+         "(x & y) & z != x & (y & z) for", x, y, z)
+    check((x | y) | z == x | (y | z),
+         "(x | y) | z != x | (y | z) for", x, y, z)
+    check((x ^ y) ^ z == x ^ (y ^ z),
+         "(x ^ y) ^ z != x ^ (y ^ z) for", x, y, z)
+    check(x & (y | z) == (x & y) | (x & z),
+         "x & (y | z) != (x & y) | (x & z) for", x, y, z)
+    check(x | (y & z) == (x | y) & (x | z),
+         "x | (y & z) != (x | y) & (x | z) for", x, y, z)
+
+def test_bitop_identities(maxdigits=MAXDIGITS):
+    print "long bit-operation identities"
+    for x in special:
+        test_bitop_identities_1(x)
+    digits = range(1, maxdigits+1)
+    for lenx in digits:
+        x = getran(lenx)
+        test_bitop_identities_1(x)
+        for leny in digits:
+            y = getran(leny)
+            test_bitop_identities_2(x, y)
+            test_bitop_identities_3(x, y, getran((lenx + leny)/2))
+
+# ------------------------------------------------------ hex oct str atol
+
+def slow_format(x, base):
+    if (x, base) == (0, 8):
+        # this is an oddball!
+        return "0L"
+    digits = []
+    sign = 0
+    if x < 0:
+        sign, x = 1, -x
+    while x:
+        x, r = divmod(x, base)
+        digits.append(int(r))
+    digits.reverse()
+    digits = digits or [0]
+    return '-'[:sign] + \
+           {8: '0', 10: '', 16: '0x'}[base] + \
+           join(map(lambda i: "0123456789ABCDEF"[i], digits), '') + \
+           "L"
+
+def test_format_1(x):
+    from string import atol
+    for base, mapper in (8, oct), (10, str), (16, hex):
+        got = mapper(x)
+        expected = slow_format(x, base)
+        check(got == expected, mapper.__name__, "returned",
+              got, "but expected", expected, "for", x)
+        check(atol(got, 0) == x, 'atol("%s", 0) !=' % got, x)
+
+def test_format(maxdigits=MAXDIGITS):
+    print "long str/hex/oct/atol"
+    for x in special:
+        test_format_1(x)
+    for i in range(10):
+        for lenx in range(1, maxdigits+1):
+            x = getran(lenx)
+            test_format_1(x)
+
+# ----------------------------------------------------------------- misc
+
+def test_misc(maxdigits=MAXDIGITS):
+    print "long miscellaneous operations"
+    import sys
+
+    # check the extremes in int<->long conversion
+    hugepos = sys.maxint
+    hugeneg = -hugepos - 1
+    hugepos_aslong = long(hugepos)
+    hugeneg_aslong = long(hugeneg)
+    check(hugepos == hugepos_aslong, "long(sys.maxint) != sys.maxint")
+    check(hugeneg == hugeneg_aslong,
+        "long(-sys.maxint-1) != -sys.maxint-1")
+
+    # long -> int should not fail for hugepos_aslong or hugeneg_aslong
+    try:
+        check(int(hugepos_aslong) == hugepos,
+              "converting sys.maxint to long and back to int fails")
+    except OverflowError:
+        raise TestFailed, "int(long(sys.maxint)) overflowed!"
+    try:
+        check(int(hugeneg_aslong) == hugeneg,
+              "converting -sys.maxint-1 to long and back to int fails")
+    except OverflowError:
+        raise TestFailed, "int(long(-sys.maxint-1)) overflowed!"
+
+    # but long -> int should overflow for hugepos+1 and hugeneg-1
+    x = hugepos_aslong + 1
+    try:
+        int(x)
+        raise ValueError
+    except OverflowError:
+        pass
+    except:
+        raise TestFailed, "int(long(sys.maxint) + 1) didn't overflow"
+
+    x = hugeneg_aslong - 1
+    try:
+        int(x)
+        raise ValueError
+    except OverflowError:
+        pass
+    except:
+        raise TestFailed, "int(long(-sys.maxint-1) - 1) didn't overflow"
+
+# ---------------------------------------------------------------- do it
+
+test_division()
+test_bitop_identities()
+test_format()
+test_misc()
+