Separate the GenerateRandomAlphaOnlyString function from stringutils

Signed-off-by: chaowang <chaowang@localhost.localdomain>
Upstream-commit: 7c35a2418265336a572976e2ced378ef4b6f1666
Component: engine

components/engine/internal/testutil/stringutils_test.go

@@ -0,0 +1,33 @@
+package testutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func testLengthHelper(generator func(int) string, t *testing.T) {
+	expectedLength := 20
+	s := generator(expectedLength)
+	assert.Equal(t, expectedLength, len(s))
+}
+
+func testUniquenessHelper(generator func(int) string, t *testing.T) {
+	repeats := 25
+	set := make(map[string]struct{}, repeats)
+	for i := 0; i < repeats; i = i + 1 {
+		str := generator(64)
+		assert.Equal(t, 64, len(str))
+		_, ok := set[str]
+		assert.False(t, ok, "Random number is repeated")
+		set[str] = struct{}{}
+	}
+}
+
+func TestGenerateRandomAlphaOnlyStringLength(t *testing.T) {
+	testLengthHelper(GenerateRandomAlphaOnlyString, t)
+}
+
+func TestGenerateRandomAlphaOnlyStringUniqueness(t *testing.T) {
+	testUniquenessHelper(GenerateRandomAlphaOnlyString, t)
+}