diff --git a/spec/coverage_reporter/cli/cmd_spec.cr b/spec/coverage_reporter/cli/cmd_spec.cr
index 6c03632d..9159d3ee 100644
--- a/spec/coverage_reporter/cli/cmd_spec.cr
+++ b/spec/coverage_reporter/cli/cmd_spec.cr
@@ -2,189 +2,307 @@ require "../../spec_helper"
 require "../../../src/coverage_reporter/cli/cmd"
 
 Spectator.describe CoverageReporter::Cli do
-  subject { described_class }
+  subject { described_class.run(options, reporter) }
+
+  let(reporter) { ReporterMock.new }
 
   describe ".run" do
-    it "applies defaults" do
-      reporter = subject.run %w(--dry-run)
+    context "defaults" do
+      let(options) { %w(--dry-run) }
 
-      expect(reporter.fail_empty).to eq true
-      expect(reporter.dry_run).to eq true
-      expect(reporter.parallel).to eq false
+      it "applies defaults" do
+        expect(subject).to eq 0
+        expect(reporter.fail_empty).to eq true
+        expect(reporter.dry_run).to eq true
+        expect(reporter.parallel).to eq false
+      end
     end
 
-    it "parses overrides" do
-      reporter = subject.run %w(--service-name overriden --dry-run --no-logo)
+    context "with overrides" do
+      let(options) { %w(--service-name overriden --dry-run --no-logo) }
 
-      expect(reporter.dry_run).to eq true
-      expect(reporter.overrides.try(&.to_h)).to eq({
-        :service_name => "overriden",
-      })
+      it "parses overrides" do
+        expect(subject).to eq 0
+        expect(reporter.dry_run).to eq true
+        expect(reporter.overrides.try(&.to_h)).to eq({
+          :service_name => "overriden",
+        })
+      end
     end
 
-    it "parses overrides" do
-      reporter = subject.run %w(
-        report
-        --parallel
-        -j super-flag
-        --base-path src/*
-        --service-name=service-name
-        --service-job-id=job-id
-        --service-build-url=build-url
-        --service-job-url=job-url
-        --service-branch=branch
-        --service-pull-request=pr
-        --build-number=build-number
-        --compare-ref=develop
-        --dry-run
-      )
-
-      expect(reporter.job_flag_name).to eq "super-flag"
-      expect(reporter.parallel).to eq true
-      expect(reporter.compare_ref).to eq "develop"
-      expect(reporter.dry_run).to eq true
-      expect(reporter.base_path).to eq "src/*"
-      expect(reporter.overrides.try(&.to_h)).to eq({
-        :service_name         => "service-name",
-        :service_number       => "build-number",
-        :service_job_id       => "job-id",
-        :service_build_url    => "build-url",
-        :service_job_url      => "job-url",
-        :service_branch       => "branch",
-        :service_pull_request => "pr",
-      })
+    context "with more overrides" do
+      let(options) do
+        %w(
+          report
+          --parallel
+          -j super-flag
+          --base-path src/*
+          --service-name=service-name
+          --service-job-id=job-id
+          --service-build-url=build-url
+          --service-job-url=job-url
+          --service-branch=branch
+          --service-pull-request=pr
+          --build-number=build-number
+          --compare-ref=develop
+          --dry-run
+        )
+      end
+
+      it "parses overrides" do
+        expect(subject).to eq 0
+        expect(reporter.job_flag_name).to eq "super-flag"
+        expect(reporter.parallel).to eq true
+        expect(reporter.compare_ref).to eq "develop"
+        expect(reporter.dry_run).to eq true
+        expect(reporter.base_path).to eq "src/*"
+        expect(reporter.overrides.try(&.to_h)).to eq({
+          :service_name         => "service-name",
+          :service_number       => "build-number",
+          :service_job_id       => "job-id",
+          :service_build_url    => "build-url",
+          :service_job_url      => "job-url",
+          :service_branch       => "branch",
+          :service_pull_request => "pr",
+        })
+      end
+    end
+
+    context "with new args" do
+      let(options) do
+        %w(
+          report
+          --parallel
+          -j super-flag
+          --base-path src/*
+          --service-name=service-name
+          --job-id=job-id
+          --build-url=build-url
+          --job-url=job-url
+          --branch=branch
+          --pull-request=pr
+          --build-number=build-number
+          --compare-ref=develop
+          --attempt=4
+          --dry-run
+        )
+      end
+
+      it "parses overrides (new args)" do
+        expect(subject).to eq 0
+        expect(reporter.job_flag_name).to eq "super-flag"
+        expect(reporter.parallel).to eq true
+        expect(reporter.compare_ref).to eq "develop"
+        expect(reporter.dry_run).to eq true
+        expect(reporter.base_path).to eq "src/*"
+        expect(reporter.overrides.try(&.to_h)).to eq({
+          :service_name         => "service-name",
+          :service_number       => "build-number",
+          :service_job_id       => "job-id",
+          :service_build_url    => "build-url",
+          :service_job_url      => "job-url",
+          :service_branch       => "branch",
+          :service_pull_request => "pr",
+          :service_attempt      => "4",
+        })
+      end
     end
 
-    it "parses overrides (new args)" do
-      reporter = subject.run %w(
-        report
-        --parallel
-        -j super-flag
-        --base-path src/*
-        --service-name=service-name
-        --job-id=job-id
-        --build-url=build-url
-        --job-url=job-url
-        --branch=branch
-        --pull-request=pr
-        --build-number=build-number
-        --compare-ref=develop
-        --attempt=4
-        --dry-run
-      )
-
-      expect(reporter.job_flag_name).to eq "super-flag"
-      expect(reporter.parallel).to eq true
-      expect(reporter.compare_ref).to eq "develop"
-      expect(reporter.dry_run).to eq true
-      expect(reporter.base_path).to eq "src/*"
-      expect(reporter.overrides.try(&.to_h)).to eq({
-        :service_name         => "service-name",
-        :service_number       => "build-number",
-        :service_job_id       => "job-id",
-        :service_build_url    => "build-url",
-        :service_job_url      => "job-url",
-        :service_branch       => "branch",
-        :service_pull_request => "pr",
-        :service_attempt      => "4",
-      })
+    context "with empty values" do
+      let(options) do
+        %w(
+          --service-name=
+          --service-job-id=
+          --service-build-url=
+          --service-job-url=
+          --service-branch=
+          --service-pull-request=
+          --done
+          --dry-run
+        )
+      end
+      it "doesn't apply empty values as overrides" do
+        expect(subject).to eq 0
+        expect(reporter.dry_run).to eq true
+        # expect(reporter.overrides.try(&.to_h)).to eq({} of Symbol => String)
+      end
     end
 
-    it "doesn't apply empty values as overrides" do
-      reporter = subject.run %w(
-        --service-name=
-        --service-job-id=
-        --service-build-url=
-        --service-job-url=
-        --service-branch=
-        --service-pull-request=
-        --done
-        --dry-run
-      )
-
-      expect(reporter.dry_run).to eq true
-      expect(reporter.overrides.try(&.to_h)).to eq({} of Symbol => String)
+    context "with allow empty option" do
+      let(options) do
+        %w(
+          --allow-empty
+          --dry-run
+        )
+      end
+      it "accepts --allow-empty option" do
+        expect(subject).to eq 0
+        expect(reporter.fail_empty).to eq false
+      end
     end
 
-    it "accepts --allow-empty option" do
-      reporter = subject.run %w(
-        --allow-empty
-        --dry-run
-      )
+    context "with carryforward option" do
+      let(options) do
+        %w(
+          --carryforward 1,2,3
+          --dry-run
+        )
+      end
 
-      expect(reporter.fail_empty).to eq false
+      it "accepts --carryforward option" do
+        expect(subject).to eq 0
+        expect(reporter.carryforward).to eq "1,2,3"
+      end
     end
 
-    it "accepts --carryforward option" do
-      reporter = subject.run %w(
-        --carryforward 1,2,3
-        --dry-run
-      )
+    context "with carryforward (new args)" do
+      let(options) do
+        %w(
+          done
+          --build-number 3
+          --carryforward 1,2,3
+          --dry-run
+        )
+      end
 
-      expect(reporter.carryforward).to eq "1,2,3"
+      it "accepts --carryforward option" do
+        expect(subject).to eq 0
+        expect(reporter.carryforward).to eq "1,2,3"
+        expect(reporter.overrides.try(&.to_h)).to eq({
+          :service_number => "3",
+        })
+      end
     end
 
-    it "accepts --carryforward option" do
-      reporter = subject.run %w(
-        done
-        --build-number 3
-        --carryforward 1,2,3
-        --dry-run
-      )
-
-      expect(reporter.carryforward).to eq "1,2,3"
-      expect(reporter.overrides.try(&.to_h)).to eq({
-        :service_number => "3",
-      })
+    context "with format option" do
+      let(options) do
+        %w(
+          --format lcov
+          --dry-run
+        )
+      end
+
+      it "accepts --format option" do
+        expect(subject).to eq 0
+        expect(reporter.coverage_format).to eq "lcov"
+      end
     end
 
-    it "accepts --format option" do
-      reporter = subject.run %w(
-        --format lcov
-        --dry-run
-      )
+    context "with filename option" do
+      let(options) do
+        %w(
+          --file spec/fixtures/lcov/test.lcov
+          --dry-run
+        )
+      end
 
-      expect(reporter.coverage_format).to eq "lcov"
+      it "accepts --filename option" do
+        expect(subject).to eq 0
+        expect(reporter.coverage_files).to eq ["spec/fixtures/lcov/test.lcov"]
+      end
     end
 
-    it "accepts --filename option" do
-      reporter = subject.run %w(
-        --file spec/fixtures/lcov/test.lcov
-        --dry-run
-      )
+    context "with multiple files report" do
+      let(options) do
+        %w(
+          report
+          spec/fixtures/lcov/test.lcov
+          spec/fixtures/lcov/test.lcov
+          spec/fixtures/lcov/empty.lcov
+          --dry-run
+        )
+      end
 
-      expect(reporter.coverage_files).to eq ["spec/fixtures/lcov/test.lcov"]
+      it "reports multiple files" do
+        expect(subject).to eq 0
+        expect(reporter.coverage_files).to eq [
+          "spec/fixtures/lcov/test.lcov",
+          "spec/fixtures/lcov/empty.lcov",
+        ]
+      end
     end
 
-    it "reports multiple files" do
-      reporter = subject.run %w(
-        report
-        spec/fixtures/lcov/test.lcov
-        spec/fixtures/lcov/test.lcov
-        spec/fixtures/lcov/empty.lcov
-        --dry-run
-      )
-
-      expect(reporter.coverage_files).to eq [
-        "spec/fixtures/lcov/test.lcov",
-        "spec/fixtures/lcov/empty.lcov",
-      ]
+    context "with -- separator" do
+      let(options) do
+        %w(
+          report
+          --dry-run
+          --
+          spec/fixtures/lcov/test.lcov
+          spec/fixtures/lcov/test.lcov
+          spec/fixtures/lcov/empty.lcov
+        )
+      end
+
+      it "reports multiple files after --" do
+        expect(subject).to eq 0
+        expect(reporter.coverage_files).to eq [
+          "spec/fixtures/lcov/test.lcov",
+          "spec/fixtures/lcov/empty.lcov",
+        ]
+      end
     end
 
-    it "reports multiple files after --" do
-      reporter = subject.run %w(
-        report
-        --dry-run
-        --
-        spec/fixtures/lcov/test.lcov
-        spec/fixtures/lcov/test.lcov
-        spec/fixtures/lcov/empty.lcov
-      )
-
-      expect(reporter.coverage_files).to eq [
-        "spec/fixtures/lcov/test.lcov",
-        "spec/fixtures/lcov/empty.lcov",
-      ]
+    context "when raises an error" do
+      mock ReporterMock
+
+      let(reporter) { mock(ReporterMock) }
+      let(options) { %w(report) }
+
+      context "internal server error" do
+        let(error) do
+          CoverageReporter::Api::InternalServerError.new(HTTP::Client::Response.new(500, ""))
+        end
+
+        it "returns 1" do
+          allow(reporter).to receive(:report).and_raise(error)
+          expect(subject).to eq 1
+        end
+      end
+
+      context "unprocessable entity" do
+        let(error) do
+          CoverageReporter::Api::UnprocessableEntity.new(HTTP::Client::Response.new(422, ""))
+        end
+
+        it "returns 1" do
+          allow(reporter).to receive(:report).and_raise(error)
+          expect(subject).to eq 1
+        end
+      end
+
+      context "other HTTP error" do
+        let(error) do
+          CoverageReporter::Api::HTTPError.new(HTTP::Client::Response.new(403, ""))
+        end
+
+        it "returns 1" do
+          allow(reporter).to receive(:report).and_raise(error)
+          expect(subject).to eq 1
+        end
+      end
+
+      context "internal logic error" do
+        let(error) do
+          CoverageReporter::BaseException.new
+        end
+
+        it "returns 1" do
+          allow(reporter).to receive(:report).and_raise(error)
+          expect(subject).to eq 1
+        end
+      end
+
+      context "internal logic error (with don't fail flag)" do
+        let(error) do
+          CoverageReporter::BaseException.new(fail: false)
+        end
+
+        it "returns 1" do
+          allow(reporter).to receive(:report).and_raise(error)
+          expect(subject).to eq 0
+        end
+      end
     end
   end
 end
diff --git a/spec/spec_helper.cr b/spec/spec_helper.cr
index f5146093..3c33c0ca 100644
--- a/spec/spec_helper.cr
+++ b/spec/spec_helper.cr
@@ -1,4 +1,5 @@
 require "../src/coverage_reporter"
+require "./support/*"
 
 require "webmock"
 require "spectator"
@@ -9,6 +10,6 @@ Spectator.configure do |config|
 
   config.before_suite do
     ENV.clear
-    CoverageReporter::Log.set(CoverageReporter::Log::Level::Error)
+    CoverageReporter::Log.set(CoverageReporter::Log::Level::Suppress)
   end
 end
diff --git a/spec/support/reporter_mock.cr b/spec/support/reporter_mock.cr
new file mode 100644
index 00000000..be66f52f
--- /dev/null
+++ b/spec/support/reporter_mock.cr
@@ -0,0 +1,28 @@
+class ReporterMock
+  alias Settings = String | Bool | Nil | Array(String) | CoverageReporter::CI::Options
+  getter settings : Hash(Symbol, Settings)
+
+  def initialize(*args, **kwargs)
+    @settings = {} of Symbol => Settings
+  end
+
+  def configure(*args, **kwargs)
+    @settings = kwargs.to_h
+  end
+
+  def report
+  end
+
+  def parallel_done
+  end
+
+  def overrides : CoverageReporter::CI::Options
+    settings[:overrides].as(CoverageReporter::CI::Options)
+  end
+
+  macro method_missing(key)
+    def {{ key.id }}
+      settings[{{ key.symbolize }}]
+    end
+  end
+end
diff --git a/src/cli.cr b/src/cli.cr
index efd8d5d5..9ed65213 100644
--- a/src/cli.cr
+++ b/src/cli.cr
@@ -1,3 +1,3 @@
 require "./coverage_reporter/cli/cmd"
 
-CoverageReporter::Cli.run
+exit CoverageReporter::Cli.run
diff --git a/src/coverage_reporter/cli/cmd.cr b/src/coverage_reporter/cli/cmd.cr
index 02d99d3e..9652a9be 100644
--- a/src/coverage_reporter/cli/cmd.cr
+++ b/src/coverage_reporter/cli/cmd.cr
@@ -5,11 +5,11 @@ require "colorize"
 module CoverageReporter::Cli
   extend self
 
-  def run(args = ARGV)
+  def run(args = ARGV, reporter = CoverageReporter::Reporter.new)
     opts = parse_args(args)
     greet(opts.no_logo?)
 
-    reporter = CoverageReporter::Reporter.new(
+    reporter.configure(
       base_path: opts.base_path,
       carryforward: opts.carryforward,
       compare_ref: opts.compare_ref,
@@ -31,22 +31,22 @@ module CoverageReporter::Cli
       reporter.report
     end
 
-    reporter
+    0
   rescue ex : BaseException
     Log.error ex.message
-    exit(ex.fail? ? 1 : 0)
+    ex.fail? ? 1 : 0
   rescue ex : Socket::Error
     Log.error ex.message
-    exit 1
+    1
   rescue ex : ArgumentError
     Log.error <<-ERROR
     Oops! #{ex.message}
     Coveralls Coverage Reporter v#{CoverageReporter::VERSION}
     ERROR
-    exit 1
+    1
   rescue ex : Api::InternalServerError
     Log.error "⚠️ Internal server error. Please contact Coveralls team."
-    exit 1
+    1
   rescue ex : Api::UnprocessableEntity
     Log.error <<-ERROR
     ---
@@ -58,7 +58,7 @@ module CoverageReporter::Cli
     More info/troubleshooting here: https://docs.coveralls.io
     - 💛, Coveralls
     ERROR
-    exit 1
+    1
   rescue ex : Api::HTTPError
     Log.error <<-ERROR
     HTTP error:
@@ -67,12 +67,12 @@ module CoverageReporter::Cli
     Message: #{ex.response}
     ---
     ERROR
-    exit 1
+    1
   rescue ex
     raise(ex) if opts.try(&.debug?)
 
     Log.error ex.inspect
-    exit 1
+    1
   end
 
   private class Opts
diff --git a/src/coverage_reporter/log.cr b/src/coverage_reporter/log.cr
index fcf55323..db005bfa 100644
--- a/src/coverage_reporter/log.cr
+++ b/src/coverage_reporter/log.cr
@@ -9,6 +9,7 @@ module CoverageReporter
     YELLOW = Colorize::Color256.new(220) # ffaf00
 
     enum Level
+      Suppress
       Error
       Warning
       Info
diff --git a/src/coverage_reporter/reporter.cr b/src/coverage_reporter/reporter.cr
index dd5a226b..00fa97c1 100644
--- a/src/coverage_reporter/reporter.cr
+++ b/src/coverage_reporter/reporter.cr
@@ -2,19 +2,38 @@ require "./*"
 
 module CoverageReporter
   class Reporter
-    getter base_path,
-      carryforward,
-      compare_ref,
-      compare_sha,
-      config_path,
-      coverage_files,
-      coverage_format,
-      dry_run,
-      fail_empty,
-      job_flag_name,
-      overrides,
-      parallel,
-      repo_token
+    struct Settings
+      getter base_path,
+        carryforward,
+        compare_ref,
+        compare_sha,
+        config_path,
+        coverage_files,
+        coverage_format,
+        dry_run,
+        fail_empty,
+        job_flag_name,
+        overrides,
+        parallel,
+        repo_token
+
+      def initialize(
+        @base_path : String? = nil,
+        @carryforward : String? = nil,
+        @compare_ref : String? = nil,
+        @compare_sha : String? = nil,
+        @config_path : String? = nil,
+        @coverage_files : Array(String) | Nil = nil,
+        @coverage_format : String? = nil,
+        @dry_run : Bool = false,
+        @fail_empty : Bool = false,
+        @job_flag_name : String? = nil,
+        @overrides : CI::Options? = nil,
+        @parallel : Bool = false,
+        @repo_token : String? = nil
+      )
+      end
+    end
 
     class NoSourceFiles < BaseException
       def message
@@ -22,21 +41,14 @@ module CoverageReporter
       end
     end
 
-    def initialize(
-      @base_path : String?,
-      @carryforward : String?,
-      @compare_ref : String?,
-      @compare_sha : String?,
-      @config_path : String?,
-      @coverage_files : Array(String) | Nil,
-      @coverage_format : String?,
-      @dry_run : Bool,
-      @fail_empty : Bool,
-      @job_flag_name : String?,
-      @overrides : CI::Options?,
-      @parallel : Bool,
-      @repo_token : String?
-    )
+    getter settings : Settings
+
+    def initialize(*args, **kwargs)
+      @settings = Settings.new(*args, **kwargs)
+    end
+
+    def configure(*args, **kwargs)
+      initialize(*args, **kwargs)
     end
 
     # Parses the coverage reports in the current directory or the given *coverage_file*
@@ -46,15 +58,15 @@ module CoverageReporter
     # current directory will be searched for all supported report formats.
     def report
       source_files = Parser.new(
-        coverage_files: coverage_files,
-        coverage_format: coverage_format,
-        base_path: base_path,
+        coverage_files: settings.coverage_files,
+        coverage_format: settings.coverage_format,
+        base_path: settings.base_path,
       ).parse
-      raise NoSourceFiles.new(fail_empty) unless source_files.size > 0
+      raise NoSourceFiles.new(settings.fail_empty) unless source_files.size > 0
 
-      api = Api::Jobs.new(config, parallel, source_files, Git.info(config))
+      api = Api::Jobs.new(config, settings.parallel, source_files, Git.info(config))
 
-      api.send_request(dry_run)
+      api.send_request(settings.dry_run)
     end
 
     # Reports that all parallel jobs were reported and Coveralls can aggregate
@@ -64,19 +76,19 @@ module CoverageReporter
     # from a CI-specific ENV, or can be set explicitly via `COVERALLS_SERVICE_NUMBER`
     # environment variable.
     def parallel_done
-      api = Api::Webhook.new(config, carryforward || config.carryforward)
+      api = Api::Webhook.new(config, settings.carryforward || config.carryforward)
 
-      api.send_request(dry_run)
+      api.send_request(settings.dry_run)
     end
 
     private def config
       @config ||= Config.new(
-        repo_token: dry_run ? "dry-run" : repo_token,
-        flag_name: job_flag_name,
-        compare_ref: compare_ref,
-        compare_sha: compare_sha,
-        path: config_path,
-        overrides: overrides,
+        repo_token: settings.dry_run ? "dry-run" : settings.repo_token,
+        flag_name: settings.job_flag_name,
+        compare_ref: settings.compare_ref,
+        compare_sha: settings.compare_sha,
+        path: settings.config_path,
+        overrides: settings.overrides,
       )
     end
   end