Add mutant environment test list subcommand

Changelog.md

@@ -1,6 +1,12 @@
 # Unreleased
 
+* [#1205](https://github.com/mbj/mutant/pull/1205)
+
+  * Add `mutant environment test list` subcommand.
+    Useful to verify which tests mutant detects as candiates for test selection.
+
 * [#1204](https://github.com/mbj/mutant/pull/1204)
+
   * Allow constants to be passed to minitst integrations `cover` declaration.
     `cover SomeClass` is equivalent to `cover 'SomeClass*'`.
 

lib/mutant.rb

@@ -194,6 +194,7 @@ module Mutant
 require 'mutant/cli/command/environment/run'
 require 'mutant/cli/command/environment/show'
 require 'mutant/cli/command/environment/subject'
+require 'mutant/cli/command/environment/test'
 require 'mutant/cli/command/root'
 require 'mutant/runner'
 require 'mutant/runner/sink'

lib/mutant/cli/command/environment.rb

@@ -116,6 +116,10 @@ def add_runner_options(parser)
             set(mutation_timeout: Float(number))
           end
         end
+
+        def print(message)
+          world.stdout.puts(message)
+        end
       end # Run
     end # Command
   end # CLI

lib/mutant/cli/command/environment/subject.rb

@@ -25,10 +25,6 @@ def list_subjects(env)
                 print(subject.expression.syntax)
               end
             end
-
-            def print(message)
-              world.stdout.puts(message)
-            end
           end
 
           SUBCOMMANDS = [List].freeze

lib/mutant/cli/command/environment/test.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Mutant
+  module CLI
+    class Command
+      class Environment
+        class Test < self
+          NAME              = 'test'
+          SHORT_DESCRIPTION = 'test subcommands'
+
+          class List < self
+            NAME              = 'list'
+            SHORT_DESCRIPTION = 'List tests detected in the environment'
+            SUBCOMMANDS       = EMPTY_ARRAY
+
+          private
+
+            def action
+              bootstrap.fmap(&method(:list_tests))
+            end
+
+            def list_tests(env)
+              tests = env.integration.all_tests
+              print('Tests in environment: %d' % tests.length)
+              tests.each do |test|
+                print(test.identification)
+              end
+            end
+          end
+
+          SUBCOMMANDS = [List].freeze
+        end # Test
+      end # Environment
+    end # Command
+  end # CLI
+end # Mutant

lib/mutant/cli/command/root.rb

@@ -4,7 +4,7 @@ module Mutant
   module CLI
     class Command
       class Environment < self
-        SUBCOMMANDS = [Environment::Subject, Environment::Show].freeze
+        SUBCOMMANDS = [Environment::Subject, Environment::Show, Environment::Test].freeze
       end # Environment
 
       class Root < self

spec/unit/mutant/cli_spec.rb

@@ -344,26 +344,34 @@ def self.main_body
     end
 
     shared_context 'environment' do
-      let(:arguments)          { %w[run]                                              }
-      let(:bootstrap_config)   { env_config.merge(file_config).expand_defaults        }
-      let(:bootstrap_result)   { MPrelude::Either::Right.new(env)                     }
-      let(:env_result)         { instance_double(Mutant::Result::Env, success?: true) }
-      let(:expected_events)    { [license_validation_event]                           }
-      let(:expected_exit)      { true                                                 }
-      let(:file_config_result) { MPrelude::Either::Right.new(file_config)             }
-      let(:license_result)     { MPrelude::Either::Right.new(subscription)            }
-      let(:runner_result)      { MPrelude::Either::Right.new(env_result)              }
+      let(:arguments)            { %w[run]                                              }
+      let(:bootstrap_config)     { env_config.merge(file_config).expand_defaults        }
+      let(:bootstrap_result)     { MPrelude::Either::Right.new(env)                     }
+      let(:env_result)           { instance_double(Mutant::Result::Env, success?: true) }
+      let(:expected_events)      { [license_validation_event]                           }
+      let(:expected_exit)        { true                                                 }
+      let(:file_config_result)   { MPrelude::Either::Right.new(file_config)             }
+      let(:license_result)       { MPrelude::Either::Right.new(subscription)            }
+      let(:runner_result)        { MPrelude::Either::Right.new(env_result)              }
+      let(:subject_a_expression) { parse_expression('Object#send')                      }
+      let(:subjects)             { [subject_a]                                          }
+      let(:tests)                { [test_a, test_b]                                     }
+
+      let(:test_a) { instance_double(Mutant::Test, identification: 'test-a') }
+      let(:test_b) { instance_double(Mutant::Test, identification: 'test-b') }
 
       let(:env) do
         config = Mutant::Config::DEFAULT.with(
           reporter: Mutant::Reporter::CLI.build(stdout)
         )
 
-        Mutant::Env.empty(world, config).with(subjects: subjects)
+        Mutant::Env.empty(world, config)
+          .with(
+            integration: instance_double(Mutant::Integration, all_tests: tests),
+            subjects:    subjects
+          )
       end
 
-      let(:subject_a_expression) { parse_expression('Object#send') }
-
       let(:subject_a) do
         Mutant::Subject::Method::Instance.new(
           context: Mutant::Context.new(
@@ -374,12 +382,6 @@ def self.main_body
         )
       end
 
-      let(:subjects) do
-        [
-          subject_a
-        ]
-      end
-
       let(:file_config) do
         Mutant::Config::DEFAULT.with(
           integration:      'file-integration',
@@ -432,6 +434,47 @@ def self.main_body
       end
     end
 
+    context 'environment test list' do
+      include_context 'environment'
+
+      let(:arguments) { %w[environment test list] }
+
+      context 'without additional arguments' do
+        let(:expected_exit) { true }
+
+        let(:expected_events) do
+          [
+            [
+              :load_config_file,
+              world
+            ],
+            [
+              :bootstrap,
+              world,
+              bootstrap_config.inspect
+            ],
+            [
+              :stdout,
+              :puts,
+              'Tests in environment: 2'
+            ],
+            [
+              :stdout,
+              :puts,
+              'test-a'
+            ],
+            [
+              :stdout,
+              :puts,
+              'test-b'
+            ]
+          ]
+        end
+
+        include_examples 'CLI run'
+      end
+    end
+
     context 'environment subject list' do
       include_context 'environment'
 
@@ -467,6 +510,7 @@ def self.main_body
         include_examples 'CLI run'
       end
     end
+
     context 'environment show' do
       include_context 'environment'
 
@@ -481,7 +525,7 @@ def self.main_body
            Includes:        []
            Requires:        []
            Subjects:        1
-           Total-Tests:     0
+           Total-Tests:     2
            Selected-Tests:  0
            Tests/Subject:   0.00 avg
            Mutations:       0