add default separator test to dedot rest test

rest-api-spec/src/main/resources/rest-api-spec/test/ingest/80_dedot_processor.yaml

@@ -1,5 +1,5 @@
 ---
-"Test De-Dot Processor":
+"Test De-Dot Processor With Provided Separator":
   - do:
       ingest.put_pipeline:
         id: "my_pipeline"
@@ -31,3 +31,34 @@
         id: 1
   - match: { _source.a3b3c: "hello world" }
 
+---
+"Test De-Dot Processor With Default Separator":
+  - do:
+      ingest.put_pipeline:
+        id: "my_pipeline"
+        body:  >
+          {
+            "description": "_description",
+            "processors": [
+              {
+                "dedot" : {
+                }
+              }
+            ]
+          }
+  - match: { acknowledged: true }
+
+  - do:
+      index:
+        index: test
+        type: test
+        id: 1
+        pipeline: "my_pipeline"
+        body: {"a.b.c": "hello world"}
+
+  - do:
+      get:
+        index: test
+        type: test
+        id: 1
+  - match: { _source.a_b_c: "hello world" }