1 // Copyright 2013 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package rand_test 6 7 import ( 8 "crypto/rand" 9 "math/big" 10 "testing" 11 ) 12 13 // https://golang.org/issue/6849. 14 func TestPrimeSmall(t *testing.T) { 15 for n := 2; n < 10; n++ { 16 p, err := rand.Prime(rand.Reader, n) 17 if err != nil { 18 t.Fatalf("Can't generate %d-bit prime: %v", n, err) 19 } 20 if p.BitLen() != n { 21 t.Fatalf("%v is not %d-bit", p, n) 22 } 23 if !p.ProbablyPrime(32) { 24 t.Fatalf("%v is not prime", p) 25 } 26 } 27 } 28 29 // Test that passing bits < 2 causes Prime to return nil, error 30 func TestPrimeBitsLt2(t *testing.T) { 31 if p, err := rand.Prime(rand.Reader, 1); p != nil || err == nil { 32 t.Errorf("Prime should return nil, error when called with bits < 2") 33 } 34 } 35 36 func TestInt(t *testing.T) { 37 // start at 128 so the case of (max.BitLen() % 8) == 0 is covered 38 for n := 128; n < 140; n++ { 39 b := new(big.Int).SetInt64(int64(n)) 40 if i, err := rand.Int(rand.Reader, b); err != nil { 41 t.Fatalf("Can't generate random value: %v, %v", i, err) 42 } 43 } 44 } 45 46 func testIntPanics(t *testing.T, b *big.Int) { 47 defer func() { 48 if err := recover(); err == nil { 49 t.Errorf("Int should panic when called with max <= 0: %v", b) 50 } 51 }() 52 rand.Int(rand.Reader, b) 53 } 54 55 // Test that passing a new big.Int as max causes Int to panic 56 func TestIntEmptyMaxPanics(t *testing.T) { 57 b := new(big.Int) 58 testIntPanics(t, b) 59 } 60 61 // Test that passing a negative value as max causes Int to panic 62 func TestIntNegativeMaxPanics(t *testing.T) { 63 b := new(big.Int).SetInt64(int64(-1)) 64 testIntPanics(t, b) 65 } 66
