Rewrite specs and add coverage for .customize

spec/appraisal/customize_spec.rb

@@ -4,18 +4,99 @@
 
 describe Appraisal::Customize do
   let(:appraisal) { Appraisal::Appraisal.new("test", "Gemfile") }
+  let(:single_line_heading) { "This file was generated with a custom heading!" }
+  let(:multi_line_heading) do
+    <<~HEADING
+      frozen_string_literal: true
 
-  it "has defaults" do
-    expect(described_class.heading(appraisal)).to eq nil
-    expect(described_class.single_quotes).to eq false
-    expect { described_class.new }.to_not(change do
-      [described_class.heading(appraisal), described_class.single_quotes]
-    end)
+      This file was generated with a custom heading!
+    HEADING
   end
+  let(:subject) { described_class.new }
+  let(:single_line_subject) do
+    described_class.new(heading: single_line_heading)
+  end
+  let(:multi_line_single_quotes_subject) do
+    described_class.new(heading: multi_line_heading, single_quotes: true)
+  end
+
+  describe ".heading" do
+    it "returns nil if no heading is set" do
+      subject
+      expect(described_class.heading(appraisal)).to eq(nil)
+    end
+
+    it "returns the heading if set" do
+      single_line_subject
+      expect(described_class.heading(appraisal)).to eq(single_line_heading)
+    end
+
+    it "returns the heading without an trailing newline" do
+      multi_line_single_quotes_subject
+      expect(described_class.heading(appraisal)).to eq(multi_line_heading.chomp)
+      expect(described_class.heading(appraisal)).to_not end_with("\n")
+    end
+  end
+
+  describe ".single_quotes" do
+    it "returns false if not set" do
+      subject
+      expect(described_class.single_quotes).to eq(false)
+    end
+
+    it "returns true if set" do
+      multi_line_single_quotes_subject
+      expect(described_class.single_quotes).to eq(true)
+    end
+  end
+
+  describe ".customize" do
+    let(:gemfile) { "test.gemfile" }
+    let(:relative_path) { "gemfiles/#{gemfile}" }
+    let(:full_path) { "/path/to/project/#{relative_path}" }
+    before do
+      allow(appraisal).to receive(:gemfile_name).and_return(gemfile)
+      allow(appraisal).to receive(:gemfile_path).and_return(full_path)
+      allow(appraisal).to receive(:relative_gemfile_path).
+        and_return(relative_path)
+    end
+
+    it "returns nil if no heading is set" do
+      subject
+      expect(described_class.send(:customize, nil, appraisal)).to eq(nil)
+    end
+
+    it "returns the heading unchanged" do
+      single_line_subject
+      expect(described_class.send(
+               :customize,
+               single_line_heading,
+               appraisal,
+             )).to eq(single_line_heading)
+    end
+
+    it "returns the heading with the gemfile name" do
+      expect(described_class.send(
+               :customize,
+               "Gemfile: %{gemfile}", # rubocop:disable Style/FormatStringToken
+               appraisal,
+             )).to eq("Gemfile: #{gemfile}")
+    end
+
+    it "returns the heading with the gemfile path" do
+      expect(described_class.send(
+               :customize,
+               "Gemfile: %{gemfile_path}", # rubocop:disable Style/FormatStringToken
+               appraisal,
+             )).to eq("Gemfile: #{full_path}")
+    end
 
-  it "can override defaults" do
-    described_class.new(single_quotes: true, heading: "foo")
-    expect(described_class.heading(appraisal)).to eq "foo"
-    expect(described_class.single_quotes).to eq true
+    it "returns the heading with the relative gemfile path" do
+      expect(described_class.send(
+               :customize,
+               "Gemfile: %{relative_gemfile_path}", # rubocop:disable Style/FormatStringToken, Metrics/LineLength
+               appraisal,
+             )).to eq("Gemfile: #{relative_path}")
+    end
   end
 end