fix implementation detail in prg_tests & update comments

lib/go/test/prg_test.go

@@ -20,8 +20,11 @@ func TestNextUInt64NewPRG(t *testing.T) {
 		n := 1 << (1 + mrand.Intn(10))
 		classWidth := (math.MaxUint64 / uint64(n)) + 1
 
+		// using the same seed, the salt varies in getNextUInt64()
+		seed := GetRandomSeed(t)
+
 		uintf := func() (uint64, error) {
-			return getNextUInt64(t, b, adapter, prgAddress)
+			return GetNextUInt64NewPRG(t, b, adapter, prgAddress, seed)
 		}
 
 		random.BasicDistributionTest(t, uint64(n), uint64(classWidth), uintf)

lib/go/test/prg_test_helpers.go

@@ -28,18 +28,22 @@ func deployPRGContract(
 	return prgAddress
 }
 
-func getNextUInt64(
+// calls a script which creates a new PRG resource from the given seed and
+// random salt, gets the next uint64 and destroys the prg resource before
+// returning the next uint64
+func GetNextUInt64NewPRG(
 	t *testing.T,
 	b emulator.Emulator,
 	adapter *adapters.SDKAdapter,
 	prgAddress flow.Address,
+	seed []byte,
 ) (uint64, error) {
 
 	script := templates.GenerateNextUInt64NewPRG(prgAddress)
 	result, err := b.ExecuteScript(
 		script,
 		[][]byte{
-			jsoncdc.MustEncode(bytesToCadenceArray(GetRandomSeed(t))),
+			jsoncdc.MustEncode(bytesToCadenceArray(seed)),
 			jsoncdc.MustEncode(cadence.NewUInt64(GetRandomSalt(t))),
 		},
 	)
@@ -48,10 +52,10 @@ func getNextUInt64(
 		t.Log(result.Error.Error())
 	}
 
-	// return uint64(result.Value.String()), err
 	return CadenceUInt64ToUInt64(result.Value), err
 }
 
+// gets a random 32 byte array using crypto/rand
 func GetRandomSeed(t *testing.T) []byte {
 	buf := make([]byte, 32)
 
@@ -61,6 +65,7 @@ func GetRandomSeed(t *testing.T) []byte {
 	return buf
 }
 
+// gets a random uint64 using crypto/rand
 func GetRandomSalt(t *testing.T) uint64 {
 	var b [8]byte
 

transactions/pseudo-random-generator/next_uint64.cdc

@@ -1,6 +1,7 @@
 import "PseudoRandomGenerator"
 
-/// Saves and links a .PRG resource in the signer's storage and public namespace
+/// For demonstration - generates the given number of random numbers
+/// These values might be passed to a consuming contract or resource
 ///
 transaction(generationLength: Int) {
     prepare(signer: AuthAccount) {