Skip constructing Time for transactions (#575)

* Skip constructing Time for transactions

The `time` parameter was never used, but each call constructed the current time
to fill out the default value.

Default is changed to nil to preserve the API / parameter count.

* Remove third parameter usage in tests

* Remove the unused parameter from sampler

Co-authored-by: Michael Lang <mlang@newrelic.com>

lib/new_relic/agent/sql_sampler.rb

@@ -65,7 +65,7 @@ def tl_transaction_data # only used for testing
       end
 
       # This is called when we are done with the transaction.
-      def on_finishing_transaction(state, name, time=Time.now)
+      def on_finishing_transaction(state, name)
         return unless enabled?
 
         data = state.sql_sampler_transaction_data

test/new_relic/agent/pipe_channel_manager_test.rb

@@ -221,7 +221,7 @@ def create_sql_sample(sampler)
       state = NewRelic::Agent::Tracer.state
       sampler.on_start_transaction(state, Time.now)
       sampler.notice_sql("SELECT * FROM table", "ActiveRecord/Widgets/find", nil, 100, state)
-      sampler.on_finishing_transaction(state, 'noodles', Time.now)
+      sampler.on_finishing_transaction(state, 'noodles')
     end
   end
 

test/new_relic/agent/sql_sampler_test.rb

@@ -440,7 +440,7 @@ def test_merge_with_existing_trace
 
   def test_on_finishing_transaction_with_busted_transaction_state_does_not_crash
     state = NewRelic::Agent::Tracer.state
-    @sampler.on_finishing_transaction(state, "whatever", Time.now)
+    @sampler.on_finishing_transaction(state, "whatever")
   end
 
   def test_caps_collection_of_unique_statements

test/new_relic/agent/transaction_sampler_test.rb

@@ -435,6 +435,31 @@ def generate_samples(count, opts = {})
       end
     end
 
+    def run_long_sample_trace(n)
+      @sampler.on_start_transaction(@state, Time.now)
+      n.times do |i|
+        @sampler.notice_push_frame(@state)
+        yield if block_given?
+        @sampler.notice_pop_frame(@state, "node#{i}")
+      end
+      @sampler.on_finishing_transaction(@state, @txn)
+    end
+
+    def run_sample_trace(start = Time.now.to_f, stop = nil, state = @state)
+      @sampler.on_start_transaction(state, start)
+      @sampler.notice_push_frame(state)
+      @sampler.notice_sql("SELECT * FROM sandwiches WHERE bread = 'wheat'", {}, 0, state)
+      @sampler.notice_push_frame(state)
+      @sampler.notice_sql("SELECT * FROM sandwiches WHERE bread = 'white'", {}, 0, state)
+      yield if block_given?
+      @sampler.notice_pop_frame(state, "ab")
+      @sampler.notice_push_frame(state)
+      @sampler.notice_sql("SELECT * FROM sandwiches WHERE bread = 'french'", {}, 0, state)
+      @sampler.notice_pop_frame(state, "ac")
+      @sampler.notice_pop_frame(state, "a")
+      @sampler.on_finishing_transaction(state, @txn)
+    end
+
     def intrinsic_attributes_from_last_sample
       sample = NewRelic::Agent.agent.transaction_sampler.harvest!.first
       attributes_for(sample, :intrinsic)