```ruby
require 'test_helper'

describe Unitwise::Expression::Matcher do
  describe "::atom(:codes)" do
    subject { Unitwise::Expression::Matcher.atom(:primary_code)}
    it "must be an Alternative list" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse [in_i]" do
      subject.parse("[in_i]").must_equal("[in_i]")
    end
  end
  describe "::metric_atom(:names)" do
    subject { Unitwise::Expression::Matcher.metric_atom(:names)}
    it "must be an Alternative list of names" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse 'Joule'" do
      subject.parse('Joule').must_equal('Joule')
    end
  end

  describe "::atom(:slugs)" do
    subject { Unitwise::Expression::Matcher.atom(:slugs)}
    it "must be an Alternative list of slugs" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must match 'georgian_year'" do
      subject.parse("mean_gregorian_year").must_equal("mean_gregorian_year")
    end
  end

  describe "::prefix(:symbol)" do
    subject { Unitwise::Expression::Matcher.prefix(:symbol)}
    it "must be an Alternative list of symbols" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse 'h'" do
      subject.parse('h').must_equal('h')
    end
  end
end```

Adjust matcher name expectation to support updated units
user
```ruby
require 'test_helper'

describe Unitwise::Expression::Matcher do
  describe "::atom(:codes)" do
    subject { Unitwise::Expression::Matcher.atom(:primary_code)}
    it "must be an Alternative list" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse [in_i]" do
      subject.parse("[in_i]").must_equal("[in_i]")
    end
  end
  describe "::metric_atom(:names)" do
    subject { Unitwise::Expression::Matcher.metric_atom(:names)}
    it "must be an Alternative list of names" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse 'joule'" do
      subject.parse('joule').must_equal('joule')
    end
  end

  describe "::atom(:slugs)" do
    subject { Unitwise::Expression::Matcher.atom(:slugs)}
    it "must be an Alternative list of slugs" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must match 'georgian_year'" do
      subject.parse("mean_gregorian_year").must_equal("mean_gregorian_year")
    end
  end

  describe "::prefix(:symbol)" do
    subject { Unitwise::Expression::Matcher.prefix(:symbol)}
    it "must be an Alternative list of symbols" do
      subject.must_be_instance_of Parslet::Atoms::Alternative
    end
    it "must parse 'h'" do
      subject.parse('h').must_equal('h')
    end
  end
end
```
assistant