Test rate aggregation on partial buckets (#97168)

Author: salvatore-campagna

x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/analytics/rate.yml

@@ -442,3 +442,100 @@
   - close_to: { aggregations.ts.buckets.0.rate-month.value: { value: 63958020.00, error: 0.01 }}
   - close_to: { aggregations.ts.buckets.0.rate-quarter.value: { value: 191874060.00, error: 0.01 }}
   - close_to: { aggregations.ts.buckets.0.rate-year.value: { value: 767496240.00, error: 0.01 }}
+
+---
+"rate aggregation on counter field partial bucket":
+  - skip:
+      version: " - 8.6.99"
+      reason: "counter field support added in 8.7"
+      features: close_to
+
+  - do:
+      indices.create:
+        index: test-rate
+        body:
+          settings:
+            index:
+              mode: time_series
+              routing_path: [ host ]
+              time_series:
+                start_time: 2021-04-28T00:00:00Z
+                end_time: 2021-04-29T00:00:00Z
+          mappings:
+            properties:
+              "@timestamp":
+                type: date
+              host:
+                type: keyword
+                time_series_dimension: true
+              bytes_counter:
+                type: long
+                time_series_metric: counter
+
+  - do:
+      bulk:
+        refresh: true
+        index: test-rate
+        body:
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:04.000Z", "host": "one", "bytes_counter": 1000 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:14.000Z", "host": "one", "bytes_counter": 1100 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:24.000Z", "host": "one", "bytes_counter": 1200 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:34.000Z", "host": "one", "bytes_counter": 1250 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:44.000Z", "host": "one", "bytes_counter": 1310 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:54.000Z", "host": "one", "bytes_counter": 1350 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:01.000Z", "host": "two", "bytes_counter": 1000 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:11.000Z", "host": "two", "bytes_counter": 1100 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:21.000Z", "host": "two", "bytes_counter": 1200 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:31.000Z", "host": "two", "bytes_counter": 1250 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:41.000Z", "host": "two", "bytes_counter": 1310 }'
+          - '{"index": {}}'
+          - '{"@timestamp": "2021-04-28T18:01:51.000Z", "host": "two", "bytes_counter": 1350 }'
+
+  - do:
+      search:
+        index: test-rate
+        body:
+          size: 0
+          query:
+            bool:
+              filter:
+                range:
+                  "@timestamp":
+                    gte: "2021-04-28T18:01:03.000Z"
+                    lte: "2021-04-28T18:18:00.000Z"
+          aggs:
+            date_histogram:
+              date_histogram:
+                field: "@timestamp"
+                calendar_interval: 1h
+                time_zone: Europe/Ljubljana
+                min_doc_count: 1
+              aggs:
+                counter_rate:
+                  time_series:
+                    keyed: false
+                  aggs:
+                    bytes_counter_rate:
+                      rate:
+                        field: bytes_counter
+                        unit: second
+
+  - match: { hits.total.value: 11 }
+  - length: { aggregations.date_histogram.buckets: 1 }
+  - match: { aggregations.date_histogram.buckets.0.key_as_string: "2021-04-28T20:00:00.000+02:00" }
+  - match: { aggregations.date_histogram.buckets.0.doc_count: 11 }
+  # NOTE: (1350 - 1000) / (54 - 4) = 350 / 50 = 7.0
+  - close_to: { aggregations.date_histogram.buckets.0.counter_rate.buckets.0.bytes_counter_rate.value: { value: 7.00, error: 0.01 } }
+  # NOTE: (1350 - 1100) / (51 - 11) = 250 / 40 = 6.25 (we filter out the first sample due to the bool range filter)
+  - close_to: { aggregations.date_histogram.buckets.0.counter_rate.buckets.1.bytes_counter_rate.value: { value: 6.25, error: 0.01 } }