fix: generate key back to user (#22)

* fix: generate key back to user

Author: jianggang

src/main/java/com/featureprobe/sdk/server/model/Split.java

@@ -36,6 +36,7 @@ public Split(List<List<List<Integer>>> distribution) {
 
     public HitResult findIndex(FPUser user, String toggleKey) {
         String hashKey = user.getKey() != null ? user.getKey() : String.valueOf(System.nanoTime());
+        user.stableRollout(hashKey);
         if (StringUtils.isNotBlank(bucketBy)) {
             if (user.containAttr(bucketBy)) {
                 hashKey = user.getAttr(bucketBy);

src/test/groovy/com/featureprobe/sdk/server/SplitSpec.groovy

@@ -27,5 +27,16 @@ class SplitSpec extends Specification {
         }
     }
 
+    def "User not has key"() {
+        when:
+        user = new FPUser()
+        def result1 = split.findIndex(user, "test_toggle_key")
+        def key1 = user.key
+        def result2 = split.findIndex(user, "test_toggle_key")
+        def key2 = user.key
+        then:
+        key1 == key2
+        result1.index.get() == result2.index.get()
+    }
 
 }