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math/big: test both bitLen and bitLen_g

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Also: simpler, more direct test.

R=golang-dev, dave.andersen
CC=golang-dev
https://golang.org/cl/5573070
This commit is contained in:
Robert Griesemer 2012-01-26 10:08:21 -08:00
parent 71b1c6d3c9
commit 8a90a8861f
1 changed files with 12 additions and 20 deletions
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32
src/pkg/math/big/arith_test.go
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@ -334,27 +334,19 @@ func TestMulAddWWW(t *testing.T) {
}
}
func testWordBitLen(t *testing.T, fname string, f func(Word) int) {
for i := 0; i <= _W; i++ {
x := Word(1) << uint(i-1) // i == 0 => x == 0
n := f(x)
if n != i {
t.Errorf("got %d; want %d for %s(%#x)", n, i, fname, x)
}
}
}
func TestWordBitLen(t *testing.T) {
// Test every possible output of bitLen with the high bit set
// and then with all bits below max set
z := bitLen(0)
if z != 0 {
t.Errorf("0 got %d want 0", z)
}
x := Word(1) // Will be ...00010000...
y := Word(1) // Will be ...00011111...
for i := 1; i <= _W; i++ {
z = bitLen(x)
if z != i {
t.Errorf("%x got %d want %d", x, z, i)
}
z = bitLen(y)
if z != i {
t.Errorf("%x got %d want %d", y, z, i)
}
x <<= 1
y = (y << 1) | 0x1
}
testWordBitLen(t, "bitLen", bitLen)
testWordBitLen(t, "bitLen_g", bitLen_g)
}
// runs b.N iterations of bitLen called on a Word containing (1 << nbits)-1.