feature: add unit testsTestCoverage module

assets/unit/simple_incorrect_script

@@ -0,0 +1 @@
+Pattern(some parameters)

unit/spec_helper.rb

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+# frozen_string_literal: true
+
+require 'rspec'

unit/test_coverage/test_coverage_spec.rb

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+# frozen_string_literal: true
+
+require 'spec_helper'
+require_relative '../../lib/coverage/test_coverage'
+
+describe TestCoverage do
+  let(:json) { described_class.get_api }
+  let(:redactors) { described_class.redactors }
+  let(:result_json) { described_class.run(json) }
+
+  it 'json that should have expected fields' do
+    hash = JSON.parse(json)
+    expect(hash).to be_an(Hash)
+    expect(hash.length).to eq(4)
+    hash.each do |key, _value|
+      expect(redactors.key(key)).to be_truthy
+    end
+  end
+
+  it 'run result should be json [String] with expected fields' do
+    hash = JSON.parse(result_json)
+    expect(hash).to be_an(Hash)
+    expect(hash.length).to eq(4)
+    hash.each do |key, _value|
+      expect(redactors.key(key)).to be_truthy
+    end
+  end
+
+  describe described_class::Matcher do
+    let(:path) { File.join(Dir.pwd, 'assets', 'unit') }
+
+    it 'true when found' do
+      matcher = described_class.new('Pattern', path)
+      expect(matcher).to be_pattern_found
+    end
+
+    it 'false when not found' do
+      matcher = described_class.new('abracadabra', path)
+      expect(matcher).not_to be_pattern_found
+    end
+  end
+end