Add Tim Peters' test for long ints

1 files changed, 139 insertions, 0 deletions

diff --git a/Lib/test/test_long.py b/Lib/test/test_long.py
new file mode 100644
index 0000000..a11b10f
--- /dev/null
+++ b/Lib/test/test_long.py
@@ -0,0 +1,139 @@
+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
+
+# ------------------------------------------------------------ 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 random long consisting of ndigits random digits (relative to base
+# BASE).  The sign bit is also random.
+
+def getran(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 == ~~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 + ~x for", x)
+    for s in range(2*SHIFT):
+        check( ((x >> s) << s) | (x & ((1L << s) - 1)) == x,
+              "((x >> s) << s) | (x & ((1L << s) - 1)) != x for",
+                x, s)
+
+def test_bitop_identities_2(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) | (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"
+    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
+
+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
+    marks = "0123456789ABCDEF"
+    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, marks=marks: marks[i], digits), '') + \
+           "L"
+
+def test_format_1(x):
+    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)
+
+def test_format(maxdigits=MAXDIGITS):
+    print "long str/hex/oct"
+    for i in range(10):
+        for lenx in range(1, maxdigits+1):
+            x = getran(lenx)
+            test_format_1(x)
+
+# ---------------------------------------------------------------- do it
+
+test_division()
+test_bitop_identities()
+test_format()
+