Remove tests dependency on filter multiline

Some of the test were still depending on the multiline filter, this
filter is now shipped anymore with Logstash. I've keep the same logic
but created a simple dummy filter.

Fixes #8284

logstash-core/spec/logstash/pipeline_pq_file_spec.rb

@@ -1,8 +1,8 @@
 # encoding: utf-8
 require "spec_helper"
 require "logstash/inputs/generator"
-require "logstash/filters/multiline"
 require_relative "../support/helpers"
+require_relative "../support/mocks_classes"
 
 class PipelinePqFileOutput < LogStash::Outputs::Base
   config_name "pipelinepqfileoutput"
@@ -40,7 +40,7 @@ describe LogStash::Pipeline do
   let(:pipeline_settings_obj) { LogStash::SETTINGS.clone }
   let(:pipeline_id) { "main" }
 
-  let(:multiline_id) { "my-multiline" }
+  let(:dummy_id) { "my-dummyid" }
   let(:output_id) { "my-pipelinepqfileoutput" }
   let(:generator_id) { "my-generator" }
   let(:config) do
@@ -52,10 +52,8 @@ describe LogStash::Pipeline do
       }
     }
     filter {
-      multiline {
-        id => "#{multiline_id}"
-        pattern => "hello"
-        what => next
+      dummyfilter {
+        id => "#{dummy_id}"
       }
     }
     output {
@@ -98,7 +96,7 @@ describe LogStash::Pipeline do
     allow(PipelinePqFileOutput).to receive(:new).with(any_args).and_return(counting_output)
     allow(LogStash::Plugin).to receive(:lookup).with("input", "generator").and_return(LogStash::Inputs::Generator)
     allow(LogStash::Plugin).to receive(:lookup).with("codec", "plain").and_return(LogStash::Codecs::Plain)
-    allow(LogStash::Plugin).to receive(:lookup).with("filter", "multiline").and_return(LogStash::Filters::Multiline)
+    allow(LogStash::Plugin).to receive(:lookup).with("filter", "dummyfilter").and_return(LogStash::Filters::DummyFilter)
     allow(LogStash::Plugin).to receive(:lookup).with("output", "pipelinepqfileoutput").and_return(PipelinePqFileOutput)
 
     pipeline_workers_setting = LogStash::SETTINGS.get_setting("pipeline.workers")

logstash-core/spec/logstash/pipeline_spec.rb

@@ -1,7 +1,7 @@
 # encoding: utf-8
 require "spec_helper"
 require "logstash/inputs/generator"
-require "logstash/filters/multiline"
+require "logstash/filters/drop"
 require_relative "../support/mocks_classes"
 require_relative "../support/helpers"
 require_relative "../logstash/pipeline_reporter_spec" # for DummyOutput class
@@ -411,19 +411,12 @@ describe LogStash::Pipeline do
     context "cancelled events should not propagate down the filters" do
       config <<-CONFIG
         filter {
-          multiline {
-           pattern => "hello"
-           what => next
-          }
-          multiline {
-           pattern => "hello"
-           what => next
-          }
+          drop {}
         }
       CONFIG
 
       sample("hello") do
-        expect(subject.get("message")).to eq("hello")
+        expect(subject).to eq(nil)
       end
     end
 
@@ -433,19 +426,10 @@ describe LogStash::Pipeline do
           clone {
             clones => ["clone1"]
           }
-          multiline {
-            pattern => "bar"
-            what => previous
-          }
         }
       CONFIG
-
       sample(["foo", "bar"]) do
-        expect(subject.size).to eq(2)
-        expect(subject[0].get("message")).to eq("foo\nbar")
-        expect(subject[0].get("type")).to be_nil
-        expect(subject[1].get("message")).to eq("foo\nbar")
-        expect(subject[1].get("type")).to eq("clone1")
+        expect(subject.size).to eq(4)
       end
     end
   end
@@ -797,8 +781,8 @@ describe LogStash::Pipeline do
     let(:pipeline_settings) { { "pipeline.id" => pipeline_id } }
     let(:pipeline_id) { "main" }
     let(:number_of_events) { 420 }
-    let(:multiline_id) { "my-multiline" }
-    let(:multiline_id_other) { "my-multiline_other" }
+    let(:dummy_id) { "my-multiline" }
+    let(:dummy_id_other) { "my-multiline_other" }
     let(:dummy_output_id) { "my-dummyoutput" }
     let(:generator_id) { "my-generator" }
     let(:config) do
@@ -810,15 +794,11 @@ describe LogStash::Pipeline do
         }
       }
       filter {
-         multiline {
-              id => "#{multiline_id}"
-              pattern => "hello"
-              what => next
+          dummyfilter {
+              id => "#{dummy_id}"
           }
-          multiline {
-               id => "#{multiline_id_other}"
-               pattern => "hello"
-               what => next
+          dummyfilter {
+               id => "#{dummy_id_other}"
            }
       }
       output {
@@ -841,7 +821,7 @@ describe LogStash::Pipeline do
       allow(::LogStash::Outputs::DummyOutput).to receive(:new).with(any_args).and_return(dummyoutput)
       allow(LogStash::Plugin).to receive(:lookup).with("input", "generator").and_return(LogStash::Inputs::Generator)
       allow(LogStash::Plugin).to receive(:lookup).with("codec", "plain").and_return(LogStash::Codecs::Plain)
-      allow(LogStash::Plugin).to receive(:lookup).with("filter", "multiline").and_return(LogStash::Filters::Multiline)
+      allow(LogStash::Plugin).to receive(:lookup).with("filter", "dummyfilter").and_return(LogStash::Filters::DummyFilter)
       allow(LogStash::Plugin).to receive(:lookup).with("output", "dummyoutput").and_return(::LogStash::Outputs::DummyOutput)
 
       pipeline_thread
@@ -885,7 +865,7 @@ describe LogStash::Pipeline do
       end
 
       it "populates the filter metrics" do
-        [multiline_id, multiline_id_other].map(&:to_sym).each do |id|
+        [dummy_id, dummy_id_other].map(&:to_sym).each do |id|
           [:in, :out].each do |metric_key|
             plugin_name = id.to_sym
             expect(collected_metric[:stats][:pipelines][:main][:plugins][:filters][plugin_name][:events][metric_key].value).to eq(number_of_events)
@@ -907,9 +887,9 @@ describe LogStash::Pipeline do
       end
 
       it "populates the name of the filter plugin" do
-        [multiline_id, multiline_id_other].map(&:to_sym).each do |id|
+        [dummy_id, dummy_id_other].map(&:to_sym).each do |id|
           plugin_name = id.to_sym
-          expect(collected_metric[:stats][:pipelines][:main][:plugins][:filters][plugin_name][:name].value).to eq(LogStash::Filters::Multiline.config_name)
+          expect(collected_metric[:stats][:pipelines][:main][:plugins][:filters][plugin_name][:name].value).to eq(LogStash::Filters::DummyFilter.config_name)
         end
       end
 

logstash-core/spec/support/mocks_classes.rb

@@ -14,6 +14,20 @@ module LogStash
       end
     end
   end
+
+  module Filters
+    class DummyFilter < LogStash::Filters::Base
+      config_name "dummyfilter"
+
+      def register
+      end
+
+      def filter(event)
+        # noop
+      end
+    end
+  end
+
   module Outputs
     class DummyOutput < LogStash::Outputs::Base
       config_name "dummyoutput"