implement mtest package

mtest/mtest.go

@@ -0,0 +1,29 @@
+// Package mtest contains types and functions which are useful when writing
+// tests
+package mtest
+
+import (
+	crand "crypto/rand"
+	"encoding/hex"
+	"math/rand"
+	"time"
+)
+
+// Rand is a public instance of rand.Rand, seeded with the current
+// nano-timestamp
+var Rand = rand.New(rand.NewSource(time.Now().UnixNano()))
+
+// RandBytes returns n random bytes
+func RandBytes(n int) []byte {
+	b := make([]byte, n)
+	if _, err := crand.Read(b); err != nil {
+		panic(err)
+	}
+	return b
+}
+
+// RandHex returns a random hex string which is n characters long
+func RandHex(n int) string {
+	b := RandBytes(hex.DecodedLen(n))
+	return hex.EncodeToString(b)
+}

mtest/mtest_test.go

@@ -0,0 +1,23 @@
+package mtest
+
+import (
+	. "testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRandBytes(t *T) {
+	var prev []byte
+	for i := 0; i < 10000; i++ {
+		curr := RandBytes(16)
+		assert.Len(t, curr, 16)
+		assert.NotEqual(t, prev, curr)
+		prev = curr
+	}
+}
+
+func TestRandHex(t *T) {
+	// RandHex is basically a wrapper of RandBytes, so we don't have to test it
+	// much
+	assert.Len(t, RandHex(16), 16)
+}