dedup skippable percentage claasses with inheritance

lib/datadog/ci/cli/cli.rb

@@ -1,3 +1,4 @@
+require "datadog"
 require "optparse"
 
 module Datadog
@@ -17,7 +18,7 @@ def self.exec(action)
       end
 
       def self.exec_skippable_tests_percentage
-        require "datadog/ci/test_optimisation/skippable_percentage"
+        require "datadog/ci/test_optimisation/skippable_percentage/calculator"
 
         ddcirb_options = {}
         OptionParser.new do |opts|
@@ -31,11 +32,11 @@ def self.exec_skippable_tests_percentage
 
         additional_rspec_opts = (ddcirb_options[:"rspec-opts"] || "").split
 
-        percentage_skipped = ::Datadog::CI::TestOptimisation::SkippablePercentage.new(
+        percentage_skipped = ::Datadog::CI::TestOptimisation::SkippablePercentage::Calculator.new(
           rspec_cli_options: additional_rspec_opts,
           verbose: !ddcirb_options[:verbose].nil?,
           spec_path: ddcirb_options[:"spec-path"] || "spec"
-        ).calculate
+        ).call
 
         if ddcirb_options[:file]
           File.write(ddcirb_options[:file], percentage_skipped)
@@ -45,7 +46,7 @@ def self.exec_skippable_tests_percentage
       end
 
       def self.exec_skippable_tests_percentage_estimate
-        require "datadog/ci/test_optimisation/estimate_skippable_percentage"
+        require "datadog/ci/test_optimisation/skippable_percentage/estimator"
 
         ddcirb_options = {}
         OptionParser.new do |opts|
@@ -56,10 +57,10 @@ def self.exec_skippable_tests_percentage_estimate
           opts.on("--verbose", "verbose output to stdout")
         end.parse!(into: ddcirb_options)
 
-        percentage_skipped = ::Datadog::CI::TestOptimisation::EstimateSkippablePercentage.new(
+        percentage_skipped = ::Datadog::CI::TestOptimisation::SkippablePercentage::Estimator.new(
           verbose: !ddcirb_options[:verbose].nil?,
           spec_path: ddcirb_options[:"spec-path"] || "spec"
-        ).calculate
+        ).call
 
         if ddcirb_options[:file]
           File.write(ddcirb_options[:file], percentage_skipped)

lib/datadog/ci/test_optimisation/skippable_percentage/base.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Datadog
+  module CI
+    module TestOptimisation
+      module SkippablePercentage
+        class Base
+          def initialize(verbose: false, spec_path: "spec")
+            @verbose = verbose
+            @spec_path = spec_path
+
+            log("Spec path: #{@spec_path}")
+          end
+
+          def call
+            0.0
+          end
+
+          private
+
+          def log(message)
+            Datadog.logger.info(message) if @verbose
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/ci/test_optimisation/skippable_percentage/calculator.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require_relative "base"
+
+module Datadog
+  module CI
+    module TestOptimisation
+      module SkippablePercentage
+        # This class calculates the percentage of tests that are going to be skipped in the next run
+        # without actually running the tests.
+        #
+        # It is useful to determine the number of parallel jobs that are required for the CI pipeline.
+        #
+        # NOTE: Only RSpec is supported at the moment.
+        class Calculator < Base
+          def initialize(rspec_cli_options: [], verbose: false, spec_path: "spec")
+            super(verbose: verbose, spec_path: spec_path)
+
+            @rspec_cli_options = rspec_cli_options || []
+          end
+
+          def call
+            require_rspec!
+            configure_datadog
+
+            exit_code = dry_run
+
+            if exit_code != 0
+              Datadog.logger.error("RSpec dry-run failed with exit code #{exit_code}")
+            end
+
+            test_optimisation = Datadog.send(:components).test_optimisation
+
+            log("Total tests count: #{test_optimisation.total_tests_count}")
+            log("Skipped tests count: #{test_optimisation.skipped_tests_count}")
+
+            (test_optimisation.skipped_tests_count.to_f / test_optimisation.total_tests_count).floor(2)
+          end
+
+          private
+
+          def require_rspec!
+            require "rspec/core"
+          rescue LoadError
+            Datadog.logger.error("RSpec is not installed, currently this functionality is only supported for RSpec.")
+            Kernel.exit(1)
+          end
+
+          def configure_datadog
+            require "datadog/ci"
+
+            Datadog.configure do |c|
+              c.ci.enabled = true
+              c.ci.itr_enabled = true
+              c.ci.retry_failed_tests_enabled = false
+              c.ci.retry_new_tests_enabled = false
+              c.ci.discard_traces = true
+              c.ci.instrument :rspec, dry_run_enabled: true
+              c.tracing.enabled = true
+            end
+          end
+
+          def dry_run
+            cli_options_array = @rspec_cli_options + ["--dry-run", @spec_path]
+
+            rspec_config_options = ::RSpec::Core::ConfigurationOptions.new(cli_options_array)
+            devnull = File.new("/dev/null", "w")
+            out = @verbose ? $stdout : devnull
+            err = @verbose ? $stderr : devnull
+
+            ::RSpec::Core::Runner.new(rspec_config_options).run(out, err)
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/ci/test_optimisation/skippable_percentage/estimator.rb

@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+require_relative "base"
+
+module Datadog
+  module CI
+    module TestOptimisation
+      module SkippablePercentage
+        # This class estimates the percentage of tests that are going to be skipped in the next run
+        # without actually running the tests. This estimate is very rough:
+        #
+        # - it counts the number of lines that start with "it" or "scenario" in the spec files, which could be inaccurate
+        #   if you use shared examples
+        # - it only counts the number of tests that could be skipped, this does not mean that they will be actually skipped:
+        #   if in this commit you replaced all the tests in your test suite with new ones, all the tests would be run (but
+        #   this is highly unlikely)
+        #
+        # It is useful to determine the number of parallel jobs that are required for the CI pipeline.
+        #
+        # NOTE: Only RSpec is supported at the moment.
+        class Estimator < Base
+          def initialize(verbose: false, spec_path: "spec")
+            super
+          end
+
+          def call
+            require "datadog/ci"
+
+            Datadog.configure do |c|
+              c.ci.enabled = true
+              c.ci.itr_enabled = true
+              c.ci.retry_failed_tests_enabled = false
+              c.ci.retry_new_tests_enabled = false
+              c.ci.discard_traces = true
+              c.tracing.enabled = true
+            end
+
+            spec_files = Dir["#{@spec_path}/**/*_spec.rb"]
+            estimated_tests_count = spec_files.sum do |file|
+              content = File.read(file)
+              content.scan(/(^\s*it\s+)|(^\s*scenario\s+)/).size
+            end
+
+            # starting and finishing a test session is required to get the skippable tests response
+            Datadog::CI.start_test_session(total_tests_count: estimated_tests_count)&.finish
+            # TODO: law of demeter violation
+            skippable_tests_count = Datadog.send(:components).test_optimisation.skippable_tests.count
+
+            log("Estimated tests count: #{estimated_tests_count}")
+            log("Skippable tests count: #{skippable_tests_count}")
+
+            [(skippable_tests_count.to_f / estimated_tests_count).floor(2), 0.99].min
+          end
+        end
+      end
+    end
+  end
+end

sig/datadog/ci/test_optimisation/skippable_percentage/base.rbs

@@ -0,0 +1,21 @@
+module Datadog
+  module CI
+    module TestOptimisation
+      module SkippablePercentage
+        class Base
+          @verbose: bool
+
+          @spec_path: String
+
+          def initialize: (?verbose: bool, ?spec_path: ::String) -> void
+
+          def call: () -> Float
+
+          private
+
+          def log: (String message) -> void
+        end
+      end
+    end
+  end
+end