test_util: add full coverage for mathutil.py

src/allmydata/test/test_util.py

@@ -3,7 +3,7 @@ def foo(): pass # keep the line number constant
 
 from twisted.trial import unittest
 
-from allmydata.util import bencode, idlib, humanreadable
+from allmydata.util import bencode, idlib, humanreadable, mathutil
 
 
 class IDLib(unittest.TestCase):
@@ -114,3 +114,95 @@ class Bencode(unittest.TestCase):
         bencode.test_unfinished_dict()
         bencode.test_unsupported_type()
 
+class Math(unittest.TestCase):
+    def test_div_ceil(self):
+        f = mathutil.div_ceil
+        self.failUnlessEqual(f(0, 1), 0)
+        self.failUnlessEqual(f(0, 2), 0)
+        self.failUnlessEqual(f(0, 3), 0)
+        self.failUnlessEqual(f(1, 3), 1)
+        self.failUnlessEqual(f(2, 3), 1)
+        self.failUnlessEqual(f(3, 3), 1)
+        self.failUnlessEqual(f(4, 3), 2)
+        self.failUnlessEqual(f(5, 3), 2)
+        self.failUnlessEqual(f(6, 3), 2)
+        self.failUnlessEqual(f(7, 3), 3)
+
+    def test_next_multiple(self):
+        f = mathutil.next_multiple
+        self.failUnlessEqual(f(5, 1), 5)
+        self.failUnlessEqual(f(5, 2), 6)
+        self.failUnlessEqual(f(5, 3), 6)
+        self.failUnlessEqual(f(5, 4), 8)
+        self.failUnlessEqual(f(5, 5), 5)
+        self.failUnlessEqual(f(5, 6), 6)
+        self.failUnlessEqual(f(32, 1), 32)
+        self.failUnlessEqual(f(32, 2), 32)
+        self.failUnlessEqual(f(32, 3), 33)
+        self.failUnlessEqual(f(32, 4), 32)
+        self.failUnlessEqual(f(32, 5), 35)
+        self.failUnlessEqual(f(32, 6), 36)
+        self.failUnlessEqual(f(32, 7), 35)
+        self.failUnlessEqual(f(32, 8), 32)
+        self.failUnlessEqual(f(32, 9), 36)
+        self.failUnlessEqual(f(32, 10), 40)
+        self.failUnlessEqual(f(32, 11), 33)
+        self.failUnlessEqual(f(32, 12), 36)
+        self.failUnlessEqual(f(32, 13), 39)
+        self.failUnlessEqual(f(32, 14), 42)
+        self.failUnlessEqual(f(32, 15), 45)
+        self.failUnlessEqual(f(32, 16), 32)
+        self.failUnlessEqual(f(32, 17), 34)
+        self.failUnlessEqual(f(32, 18), 36)
+        self.failUnlessEqual(f(32, 589), 589)
+
+    def test_pad_size(self):
+        f = mathutil.pad_size
+        self.failUnlessEqual(f(0, 4), 0)
+        self.failUnlessEqual(f(1, 4), 3)
+        self.failUnlessEqual(f(2, 4), 2)
+        self.failUnlessEqual(f(3, 4), 1)
+        self.failUnlessEqual(f(4, 4), 0)
+        self.failUnlessEqual(f(5, 4), 3)
+
+    def test_is_power_of_k(self):
+        f = mathutil.is_power_of_k
+        for i in range(1, 100):
+            if i in (1, 2, 4, 8, 16, 32, 64):
+                self.failUnless(f(i, 2), "but %d *is* a power of 2" % i)
+            else:
+                self.failIf(f(i, 2), "but %d is *not* a power of 2" % i)
+        for i in range(1, 100):
+            if i in (1, 3, 9, 27, 81):
+                self.failUnless(f(i, 3), "but %d *is* a power of 3" % i)
+            else:
+                self.failIf(f(i, 3), "but %d is *not* a power of 3" % i)
+
+    def test_next_power_of_k(self):
+        f = mathutil.next_power_of_k
+        self.failUnlessEqual(f(0,2), 1)
+        self.failUnlessEqual(f(1,2), 1)
+        self.failUnlessEqual(f(2,2), 2)
+        self.failUnlessEqual(f(3,2), 4)
+        self.failUnlessEqual(f(4,2), 4)
+        for i in range(5, 8): self.failUnlessEqual(f(i,2), 8, "%d" % i)
+        for i in range(9, 16): self.failUnlessEqual(f(i,2), 16, "%d" % i)
+        for i in range(17, 32): self.failUnlessEqual(f(i,2), 32, "%d" % i)
+        for i in range(33, 64): self.failUnlessEqual(f(i,2), 64, "%d" % i)
+        for i in range(65, 100): self.failUnlessEqual(f(i,2), 128, "%d" % i)
+
+        self.failUnlessEqual(f(0,3), 1)
+        self.failUnlessEqual(f(1,3), 1)
+        self.failUnlessEqual(f(2,3), 3)
+        self.failUnlessEqual(f(3,3), 3)
+        for i in range(4, 9): self.failUnlessEqual(f(i,3), 9, "%d" % i)
+        for i in range(10, 27): self.failUnlessEqual(f(i,3), 27, "%d" % i)
+        for i in range(28, 81): self.failUnlessEqual(f(i,3), 81, "%d" % i)
+        for i in range(82, 200): self.failUnlessEqual(f(i,3), 243, "%d" % i)
+
+    def test_ave(self):
+        f = mathutil.ave
+        self.failUnlessEqual(f([1,2,3]), 2)
+        self.failUnlessEqual(f([0,0,0,4]), 1)
+        self.failUnlessAlmostEqual(f([0.0, 1.0, 1.0]), .666666666666)
+