diff --git a/config/flay.yml b/config/flay.yml
index c4e33ae5..9d14a4ef 100644
--- a/config/flay.yml
+++ b/config/flay.yml
@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 1222
+total_score: 1177
diff --git a/lib/mutant.rb b/lib/mutant.rb
index 08866b2b..6ee095c9 100644
--- a/lib/mutant.rb
+++ b/lib/mutant.rb
@@ -168,7 +168,6 @@ require 'mutant/runner/sink'
 require 'mutant/result'
 require 'mutant/reporter'
 require 'mutant/reporter/null'
-require 'mutant/reporter/trace'
 require 'mutant/reporter/cli'
 require 'mutant/reporter/cli/printer'
 require 'mutant/reporter/cli/printer/config'
diff --git a/lib/mutant/env.rb b/lib/mutant/env.rb
index 9b40faf2..022828a8 100644
--- a/lib/mutant/env.rb
+++ b/lib/mutant/env.rb
@@ -16,18 +16,6 @@ module Mutant
       "Fix your lib to follow normal ruby semantics!\n" \
       '{Module,Class}#name should return resolvable constant name as String or nil'.freeze
 
-    # Print warning message
-    #
-    # @param [String]
-    #
-    # @return [self]
-    #
-    # @api private
-    def warn(message)
-      config.reporter.warn(message)
-      self
-    end
-
     # Kill mutation
     #
     # @param [Mutation] mutation
diff --git a/lib/mutant/matcher.rb b/lib/mutant/matcher.rb
index 3e51b7a6..7f8336b1 100644
--- a/lib/mutant/matcher.rb
+++ b/lib/mutant/matcher.rb
@@ -5,7 +5,7 @@ module Mutant
 
     # Call matcher
     #
-    # @param [Env] env
+    # @param [Env::Bootstrap] env
     #
     # @return [Enumerable<Subject>]
     #
diff --git a/lib/mutant/matcher/chain.rb b/lib/mutant/matcher/chain.rb
index 7263c378..01ba1894 100644
--- a/lib/mutant/matcher/chain.rb
+++ b/lib/mutant/matcher/chain.rb
@@ -6,7 +6,7 @@ module Mutant
 
       # Call matcher
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/filter.rb b/lib/mutant/matcher/filter.rb
index b65dda9c..5c6cc54a 100644
--- a/lib/mutant/matcher/filter.rb
+++ b/lib/mutant/matcher/filter.rb
@@ -6,7 +6,7 @@ module Mutant
 
       # Enumerate matches
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/method.rb b/lib/mutant/matcher/method.rb
index fbab1b73..94ce7dd6 100644
--- a/lib/mutant/matcher/method.rb
+++ b/lib/mutant/matcher/method.rb
@@ -18,7 +18,7 @@ module Mutant
 
       # Matched subjects
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/methods.rb b/lib/mutant/matcher/methods.rb
index 612a1cdd..7884fabc 100644
--- a/lib/mutant/matcher/methods.rb
+++ b/lib/mutant/matcher/methods.rb
@@ -14,7 +14,7 @@ module Mutant
 
       # Enumerate subjects
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/namespace.rb b/lib/mutant/matcher/namespace.rb
index 83d8984c..33e203cd 100644
--- a/lib/mutant/matcher/namespace.rb
+++ b/lib/mutant/matcher/namespace.rb
@@ -6,7 +6,7 @@ module Mutant
 
       # Enumerate subjects
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/null.rb b/lib/mutant/matcher/null.rb
index 92c7b303..846e0a74 100644
--- a/lib/mutant/matcher/null.rb
+++ b/lib/mutant/matcher/null.rb
@@ -6,7 +6,7 @@ module Mutant
 
       # Enumerate subjects
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/matcher/scope.rb b/lib/mutant/matcher/scope.rb
index fcde01a7..6ee16720 100644
--- a/lib/mutant/matcher/scope.rb
+++ b/lib/mutant/matcher/scope.rb
@@ -18,7 +18,7 @@ module Mutant
 
       # Matched subjects
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [Enumerable<Subject>]
       #
diff --git a/lib/mutant/reporter/cli.rb b/lib/mutant/reporter/cli.rb
index 213082dc..53d5fdbc 100644
--- a/lib/mutant/reporter/cli.rb
+++ b/lib/mutant/reporter/cli.rb
@@ -24,7 +24,7 @@ module Mutant
 
       # Report start
       #
-      # @param [Env] env
+      # @param [Env::Bootstrap] env
       #
       # @return [self]
       #
diff --git a/lib/mutant/reporter/cli/format.rb b/lib/mutant/reporter/cli/format.rb
index 146fa4aa..9232e507 100644
--- a/lib/mutant/reporter/cli/format.rb
+++ b/lib/mutant/reporter/cli/format.rb
@@ -7,7 +7,7 @@ module Mutant
 
         # Start representation
         #
-        # @param [Env] env
+        # @param [Env::Bootstrap] env
         #
         # @return [String]
         #
@@ -116,7 +116,7 @@ module Mutant
 
           # Format start
           #
-          # @param [Env] env
+          # @param [Env::Bootstrap] env
           #
           # @return [String]
           #
diff --git a/lib/mutant/reporter/trace.rb b/lib/mutant/reporter/trace.rb
deleted file mode 100644
index dd2100ba..00000000
--- a/lib/mutant/reporter/trace.rb
+++ /dev/null
@@ -1,36 +0,0 @@
-module Mutant
-  class Reporter
-    # Reporter to trace report calls, used as a spec adapter
-    class Trace
-      include Adamantium::Mutable, Anima.new(:start_calls, :progress_calls, :report_calls, :warn_calls)
-
-      # New trace reporter
-      #
-      # @return [Trace]
-      #
-      # @api private
-      def self.new
-        super(Hash[anima.attribute_names.map { |name| [name, []] }])
-      end
-
-      %w[start progress report warn].each do |name|
-        define_method(name) do |object|
-          public_send(:"#{name}_calls") << object
-          self
-        end
-      end
-
-      REPORT_DELAY = 0.0
-
-      # Report delay
-      #
-      # @return [Float]
-      #
-      # @api private
-      def delay
-        REPORT_DELAY
-      end
-
-    end # Tracker
-  end # reporter
-end # Mutant
diff --git a/spec/shared/method_matcher_behavior.rb b/spec/shared/method_matcher_behavior.rb
index 0920f01b..a63c7d2b 100644
--- a/spec/shared/method_matcher_behavior.rb
+++ b/spec/shared/method_matcher_behavior.rb
@@ -33,13 +33,13 @@ RSpec.shared_examples_for 'a method matcher' do
 end
 
 RSpec.shared_examples_for 'skipped candidate' do
+  before do
+    expected_warnings.each do |warning|
+      expect(env).to receive(:warn).with(warning).and_return(env)
+    end
+  end
+
   it 'does not emit matcher' do
     expect(subject).to eql([])
   end
-
-  it 'does warn' do
-    subject
-
-    expect(env.config.reporter.warn_calls).to eql(expected_warnings)
-  end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index f6a2ddea..5ebf7960 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -33,7 +33,7 @@ $LOAD_PATH << File.join(TestApp.root, 'lib')
 require 'test_app'
 
 module Fixtures
-  TEST_CONFIG = Mutant::Config::DEFAULT.with(reporter: Mutant::Reporter::Trace.new)
+  TEST_CONFIG = Mutant::Config::DEFAULT.with(reporter: Mutant::Reporter::Null.new)
   TEST_ENV    = Mutant::Env::Bootstrap.(TEST_CONFIG)
 end # Fixtures
 
@@ -42,12 +42,6 @@ module ParserHelper
     Unparser.unparse(node)
   end
 
-  def test_env
-    Fixtures::TEST_ENV.with(
-      config: Mutant::Config::DEFAULT.with(reporter: Mutant::Reporter::Trace.new)
-    )
-  end
-
   def parse(string)
     Unparser::Preprocessor.run(Parser::CurrentRuby.parse(string))
   end
diff --git a/spec/support/shared_context.rb b/spec/support/shared_context.rb
index 758867ee..6f8d02d5 100644
--- a/spec/support/shared_context.rb
+++ b/spec/support/shared_context.rb
@@ -53,7 +53,7 @@ module SharedContext
     let(:config) do
       Mutant::Config::DEFAULT.with(
         jobs:      1,
-        reporter:  Mutant::Reporter::Trace.new
+        reporter:  Mutant::Reporter::Null.new
       )
     end
 
diff --git a/spec/unit/mutant/env/boostrap_spec.rb b/spec/unit/mutant/env/boostrap_spec.rb
index b0d7eb13..84f7ee9d 100644
--- a/spec/unit/mutant/env/boostrap_spec.rb
+++ b/spec/unit/mutant/env/boostrap_spec.rb
@@ -16,7 +16,7 @@ RSpec.describe Mutant::Env::Bootstrap do
   let(:config) do
     Mutant::Config::DEFAULT.with(
       jobs:        1,
-      reporter:    Mutant::Reporter::Trace.new,
+      reporter:    instance_double(Mutant::Reporter),
       includes:    [],
       requires:    [],
       integration: integration_class,
@@ -41,12 +41,18 @@ RSpec.describe Mutant::Env::Bootstrap do
     it { should eql(expected_env) }
   end
 
+  def expect_warning
+    expect(config.reporter).to receive(:warn)
+      .with(expected_warning)
+      .and_return(config.reporter)
+  end
+
   before do
     expect(integration_class).to receive(:new)
       .with(config)
       .and_return(integration)
 
-    expect(integration).to receive(:setup).and_return(integration)
+    expect(integration).to receive_messages(setup: integration)
 
     expect(ObjectSpace).to receive(:each_object)
       .with(Module)
@@ -54,17 +60,12 @@ RSpec.describe Mutant::Env::Bootstrap do
   end
 
   describe '#warn' do
-    let(:object)  { described_class.new(config) }
-    let(:message) { instance_double(String)     }
+    let(:object)           { described_class.new(config) }
+    let(:expected_warning) { instance_double(String)     }
 
-    subject { object.warn(message) }
+    subject { object.warn(expected_warning) }
 
-    it 'reports a warning' do
-      expect { subject }
-        .to change { config.reporter.warn_calls }
-        .from([])
-        .to([message])
-    end
+    before { expect_warning }
 
     it_behaves_like 'a command method'
   end
@@ -75,6 +76,11 @@ RSpec.describe Mutant::Env::Bootstrap do
     context 'when Module#name calls result in exceptions' do
       let(:object_space_modules) { [invalid_class] }
 
+      let(:expected_warning) do
+        "Class#name from: #{invalid_class} raised an error: " \
+        "RuntimeError. #{Mutant::Env::SEMANTICS_MESSAGE}"
+      end
+
       let(:invalid_class) do
         Class.new do
           def self.name
@@ -92,17 +98,7 @@ RSpec.describe Mutant::Env::Bootstrap do
         end
       end
 
-      it 'warns via reporter' do
-        expected_warnings = [
-          "Class#name from: #{invalid_class} raised an error: " \
-          "RuntimeError. #{Mutant::Env::SEMANTICS_MESSAGE}"
-        ]
-
-        expect { subject }
-          .to change { config.reporter.warn_calls }
-          .from([])
-          .to(expected_warnings)
-      end
+      before { expect_warning }
 
       include_examples 'bootstrap call'
     end
@@ -146,6 +142,11 @@ RSpec.describe Mutant::Env::Bootstrap do
         end
       end
 
+      let(:expected_warning) do
+        "Class#name from: #{invalid_class} " \
+        "returned Object. #{Mutant::Env::SEMANTICS_MESSAGE}"
+      end
+
       after do
         # Fix Class#name so other specs do not see this one
         class << invalid_class
@@ -155,15 +156,7 @@ RSpec.describe Mutant::Env::Bootstrap do
         end
       end
 
-      it 'warns via reporter' do
-        expected_warnings = [
-          "Class#name from: #{invalid_class.inspect} returned Object. #{Mutant::Env::SEMANTICS_MESSAGE}"
-        ]
-
-        expect { subject }
-          .to change { config.reporter.warn_calls }
-          .from([]).to(expected_warnings)
-      end
+      before { expect_warning }
 
       include_examples 'bootstrap call'
     end
diff --git a/spec/unit/mutant/env_spec.rb b/spec/unit/mutant/env_spec.rb
index e80ee92d..29b376f1e 100644
--- a/spec/unit/mutant/env_spec.rb
+++ b/spec/unit/mutant/env_spec.rb
@@ -13,7 +13,7 @@ RSpec.describe Mutant::Env do
       )
     end
 
-    let(:integration) { integration_class.new(config) }
+    let(:integration) { instance_double(Mutant::Integration) }
 
     let(:config) do
       Mutant::Config::DEFAULT.with(isolation: isolation, integration: integration_class)
@@ -45,18 +45,38 @@ RSpec.describe Mutant::Env do
     end
 
     before do
-      expect(selector).to receive(:call).with(mutation_subject).and_return(tests)
-      allow(Time).to receive(:now).and_return(Time.at(0))
+      expect(selector).to receive(:call)
+        .with(mutation_subject)
+        .and_return(tests)
+
+      allow(Time).to receive_messages(now: Time.at(0))
     end
 
     context 'when isolation does not raise error' do
       let(:test_result)  { instance_double(Mutant::Result::Test, passed: false) }
 
       before do
-        expect(isolation).to receive(:call).and_yield.and_return(test_result)
-        expect(mutation_subject).to receive(:prepare).and_return(mutation_subject).ordered
-        expect(context).to receive(:root).with(s(:nil)).and_return(wrapped_node).ordered
-        expect(Mutant::Loader::Eval).to receive(:call).with(wrapped_node, mutation_subject).and_return(nil).ordered
+        expect(isolation).to receive(:call)
+          .ordered
+          .and_yield
+
+        expect(mutation_subject).to receive(:prepare)
+          .ordered
+          .and_return(mutation_subject)
+
+        expect(context).to receive(:root)
+          .with(s(:nil))
+          .and_return(wrapped_node)
+
+        expect(Mutant::Loader::Eval).to receive(:call)
+          .ordered
+          .with(wrapped_node, mutation_subject)
+          .and_return(Mutant::Loader::Eval)
+
+        expect(integration).to receive(:call)
+          .ordered
+          .with(tests)
+          .and_return(test_result)
       end
 
       include_examples 'mutation kill'
@@ -64,10 +84,18 @@ RSpec.describe Mutant::Env do
 
     context 'when isolation does raise error' do
       before do
-        expect(isolation).to receive(:call).and_raise(Mutant::Isolation::Error, 'test-error')
+        expect(isolation).to receive(:call)
+          .and_raise(Mutant::Isolation::Error, 'test-error')
       end
 
-      let(:test_result) { Mutant::Result::Test.new(tests: tests, output: 'test-error', passed: false, runtime: 0.0) }
+      let(:test_result) do
+        Mutant::Result::Test.new(
+          tests:   tests,
+          output:  'test-error',
+          passed:  false,
+          runtime: 0.0
+        )
+      end
 
       include_examples 'mutation kill'
     end
diff --git a/spec/unit/mutant/matcher/method/instance_spec.rb b/spec/unit/mutant/matcher/method/instance_spec.rb
index 73f20f14..4ea5b54b 100644
--- a/spec/unit/mutant/matcher/method/instance_spec.rb
+++ b/spec/unit/mutant/matcher/method/instance_spec.rb
@@ -2,7 +2,6 @@ RSpec.describe Mutant::Matcher::Method::Instance, '#call' do
   subject { object.call(env) }
 
   let(:object)       { described_class.new(scope, method)                }
-  let(:env)          { test_env                                          }
   let(:method_name)  { :foo                                              }
   let(:source_path)  { MutantSpec::ROOT.join('test_app/lib/test_app.rb') }
   let(:method)       { scope.instance_method(method_name)                }
@@ -11,6 +10,13 @@ RSpec.describe Mutant::Matcher::Method::Instance, '#call' do
   let(:method_arity) { 0                                                 }
   let(:base)         { TestApp::InstanceMethodTests                      }
 
+  let(:env) do
+    instance_double(
+      Mutant::Env::Bootstrap,
+      parser: Fixtures::TEST_ENV.parser
+    )
+  end
+
   def name
     node.children.fetch(0)
   end
diff --git a/spec/unit/mutant/matcher/method/singleton_spec.rb b/spec/unit/mutant/matcher/method/singleton_spec.rb
index ed5cd694..139627d6 100644
--- a/spec/unit/mutant/matcher/method/singleton_spec.rb
+++ b/spec/unit/mutant/matcher/method/singleton_spec.rb
@@ -2,7 +2,6 @@ RSpec.describe Mutant::Matcher::Method::Singleton, '#call' do
   subject { object.call(env) }
 
   let(:object)       { described_class.new(scope, method)                }
-  let(:env)          { test_env                                          }
   let(:method)       { scope.method(method_name)                         }
   let(:type)         { :defs                                             }
   let(:method_name)  { :foo                                              }
@@ -10,6 +9,13 @@ RSpec.describe Mutant::Matcher::Method::Singleton, '#call' do
   let(:base)         { TestApp::SingletonMethodTests                     }
   let(:source_path)  { MutantSpec::ROOT.join('test_app/lib/test_app.rb') }
 
+  let(:env) do
+    instance_double(
+      Mutant::Env::Bootstrap,
+      parser: Fixtures::TEST_ENV.parser
+    )
+  end
+
   def name
     node.children.fetch(1)
   end
diff --git a/spec/unit/mutant/reporter/trace_spec.rb b/spec/unit/mutant/reporter/trace_spec.rb
deleted file mode 100644
index 75b28415..00000000
--- a/spec/unit/mutant/reporter/trace_spec.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-RSpec.describe Mutant::Reporter::Trace do
-  let(:object) { described_class.new }
-
-  describe '#delay' do
-    subject { object.delay }
-
-    it { should eql(0.0) }
-  end
-
-  let(:value) { instance_double(Object) }
-
-  %i[report start progress].each do |name|
-    describe "##{name}" do
-      subject { object.public_send(name, value) }
-
-      it 'logs the value' do
-        expect { subject }
-          .to change { object.public_send("#{name}_calls") }
-          .from([])
-          .to([value])
-      end
-    end
-  end
-end