/
chain.go
73 lines (64 loc) · 1.83 KB
/
chain.go
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package algtest
import (
"math"
"math/big"
"math/rand"
"testing"
"github.com/mmcloughlin/addchain/alg"
"github.com/mmcloughlin/addchain/internal/bigint"
"github.com/mmcloughlin/addchain/internal/prime"
"github.com/mmcloughlin/addchain/internal/test"
)
// ChainAlgorithm applies a generic test suite to the algorithm a.
func ChainAlgorithm(t *testing.T, a alg.ChainAlgorithm) {
suite := ChainAlgorithmSuite(a)
suite(t)
}
// ChainAlgorithmSuite builds a generic test suite function for the algorithm a.
func ChainAlgorithmSuite(a alg.ChainAlgorithm) func(t *testing.T) {
return func(t *testing.T) {
t.Run("powers_of_two", checkPowersOfTwo(a, 100))
t.Run("binary_runs", checkBinaryRuns(a, 32))
t.Run("random_int64", checkRandomInt64s(a))
t.Run("primes", checkPrimes(a))
}
}
func checkPowersOfTwo(a alg.ChainAlgorithm, e uint) func(t *testing.T) {
return func(t *testing.T) {
n := big.NewInt(1)
for i := uint(0); i <= e; i++ {
AssertChainAlgorithmProduces(t, a, n)
n.Lsh(n, 1)
}
}
}
func checkBinaryRuns(a alg.ChainAlgorithm, n uint) func(t *testing.T) {
return func(t *testing.T) {
for i := uint(1); i <= n; i++ {
r := bigint.Pow2(i)
r.Sub(r, bigint.One())
AssertChainAlgorithmProduces(t, a, r)
}
}
}
func checkRandomInt64s(a alg.ChainAlgorithm) func(t *testing.T) {
return test.Trials(func(t *testing.T) bool {
r := rand.Int63n(math.MaxInt64)
n := big.NewInt(r)
AssertChainAlgorithmProduces(t, a, n)
return true
})
}
func checkPrimes(a alg.ChainAlgorithm) func(t *testing.T) {
// Prepare primes in a random order.
ps := []*big.Int{}
for _, p := range prime.Distinguished {
ps = append(ps, p.Int())
}
rand.Shuffle(len(ps), func(i, j int) { ps[i], ps[j] = ps[j], ps[i] })
return test.Trials(func(t *testing.T) bool {
AssertChainAlgorithmProduces(t, a, ps[0])
ps = ps[1:]
return len(ps) > 0
})
}