libpod: Ensure that generated container names are random

Fixes #15569.

Signed-off-by: Doug Rabson <dfr@rabson.org>

libpod/runtime_test.go

@@ -0,0 +1,28 @@
+package libpod
+
+import (
+	"math/rand"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_generateName(t *testing.T) {
+	state, path, _, err := getEmptyBoltState()
+	assert.NoError(t, err)
+	defer os.RemoveAll(path)
+	defer state.Close()
+
+	r := &Runtime{
+		state: state,
+	}
+
+	// Test that (*Runtime).generateName returns different names
+	// if called twice, even if the global RNG has the default
+	// seed.
+	n1, _ := r.generateName()
+	rand.Seed(1)
+	n2, _ := r.generateName()
+	assert.NotEqual(t, n1, n2)
+}