spec/policy/3scale_batcher/reports_batcher: test that reports are not…

… evicted from the dict

spec/policy/3scale_batcher/reports_batcher_spec.lua

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+local ReportsBatcher = require 'apicast.policy.3scale_batcher.reports_batcher'
+local Usage = require 'apicast.usage'
+local keys_helper = require 'apicast.policy.3scale_batcher.keys_helper'
+local resty_lock = require 'resty.lock'
+
+describe('reports batcher', function()
+  describe('.add', function()
+    before_each(function()
+      -- Stub locks. Not relevant for these tests.
+      stub(resty_lock, 'new').returns({
+        lock = function() return true end,
+        unlock = function() return true end
+      })
+    end)
+
+    local service_id = 's1'
+    local credentials = { user_key = 'uk' }
+
+    local usage = Usage.new()
+    local metric = 'm1'
+    usage:add(metric, 1)
+
+    local report_key = keys_helper.key_for_batched_report(service_id, credentials, metric)
+
+    -- Note: all these tests use a mocked instance of ngx.shared.dict.
+    -- 'safe_add()' returns 'no memory' when the dict ran out of memory and
+    -- 'exists' when the key already exists in the dict.
+
+    describe('when a report cannot be batched because the dict ran out of mem', function()
+      it('does not try to increase the value of the batched report', function()
+        local test_dict = {
+          safe_add = function(_, _, _) return nil, 'no memory' end,
+          incr = function(_, _, _) end
+        }
+        local spy_incr_dict = spy.on(test_dict, 'incr')
+        local reports_batcher = ReportsBatcher.new(test_dict, 'batched_reports_locks')
+
+        reports_batcher:add(service_id, credentials, usage)
+
+        assert.spy(spy_incr_dict).was_not_called()
+      end)
+    end)
+
+    describe('when a report already exists in the dict', function()
+      it('increases its usage', function()
+        local test_dict = {
+          safe_add = function(_, _, _) return nil, 'exists' end,
+          incr = function(_, _, _) end
+        }
+        local spy_incr_dict = spy.on(test_dict, 'incr')
+        local reports_batcher = ReportsBatcher.new(test_dict, 'batched_reports_locks')
+
+        reports_batcher:add(service_id, credentials, usage)
+
+        assert.spy(spy_incr_dict).was_called_with(test_dict, report_key, 1)
+      end)
+    end)
+
+    describe('when a report is not in the dict', function()
+      it('adds it with the given usage', function()
+        local test_dict = {
+          safe_add = function(_, _, _) return true end,
+          incr = function(_, _, _) end
+        }
+        local spy_add_dict = spy.on(test_dict, 'safe_add')
+        local spy_incr_dict = spy.on(test_dict, 'incr')
+        local reports_batcher = ReportsBatcher.new(test_dict, 'batched_reports_locks')
+
+        reports_batcher:add(service_id, credentials, usage)
+
+        assert.spy(spy_add_dict).was_called.with(test_dict, report_key, 1)
+        assert.spy(spy_incr_dict).was_not_called()
+      end)
+    end)
+  end)
+end)