tap: add tests for formula_file? and cask_file?

Library/Homebrew/tap.rb

@@ -755,13 +755,15 @@ class Tap
 
   sig { returns(Regexp) }
   def formula_file_regex
-    @formula_file_regex ||= case formula_dir.basename.to_s
+    @formula_file_regex ||= case formula_dir
-    when "Formula"
+    when path/"Formula"
       %r{^Formula(/[^/]+)+\.rb$}
-    when "HomebrewFormula"
+    when path/"HomebrewFormula"
       %r{^HomebrewFormula(/[^/]+)+\.rb$}
-    else
+    when path
       %r{^[^/]+\.rb$}
+    else
+      raise ArgumentError, "Unexpected formula_dir: #{formula_dir}"
     end
   end
   private :formula_file_regex

Library/Homebrew/test/tap_spec.rb

@@ -3,6 +3,7 @@
 RSpec.describe Tap do
   include FileUtils
 
+  alias_matcher :have_cask_file, :be_cask_file
   alias_matcher :have_formula_file, :be_formula_file
   alias_matcher :have_custom_remote, :be_custom_remote
 
@@ -631,6 +632,103 @@ RSpec.describe Tap do
         expect(homebrew_foo_tap.pypi_formula_mappings).to eq expected_result
       end
     end
+
+    describe "#formula_file?" do
+      it "matches files from Formula/" do
+        tap = described_class.fetch("hard/core")
+        FileUtils.mkdir_p(tap.path/"Formula")
+
+        %w[
+          kvazaar.rb
+          Casks/kvazaar.rb
+          Casks/k/kvazaar.rb
+          Formula/kvazaar.sh
+          HomebrewFormula/kvazaar.rb
+          HomebrewFormula/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).not_to have_formula_file(relative_path)
+        end
+
+        %w[
+          Formula/kvazaar.rb
+          Formula/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).to have_formula_file(relative_path)
+        end
+      ensure
+        FileUtils.rm_rf(tap.path.parent) if tap
+      end
+
+      it "matches files from HomebrewFormula/" do
+        tap = described_class.fetch("hard/core")
+        FileUtils.mkdir_p(tap.path/"HomebrewFormula")
+
+        %w[
+          kvazaar.rb
+          Casks/kvazaar.rb
+          Casks/k/kvazaar.rb
+          Formula/kvazaar.rb
+          Formula/k/kvazaar.rb
+          HomebrewFormula/kvazaar.sh
+        ].each do |relative_path|
+          expect(tap).not_to have_formula_file(relative_path)
+        end
+
+        %w[
+          HomebrewFormula/kvazaar.rb
+          HomebrewFormula/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).to have_formula_file(relative_path)
+        end
+      ensure
+        FileUtils.rm_rf(tap.path.parent) if tap
+      end
+
+      it "matches files from the top-level directory" do
+        tap = described_class.fetch("hard/core")
+        FileUtils.mkdir_p(tap.path)
+
+        %w[
+          kvazaar.sh
+          Casks/kvazaar.rb
+          Casks/k/kvazaar.rb
+          Formula/kvazaar.rb
+          Formula/k/kvazaar.rb
+          HomebrewFormula/kvazaar.rb
+          HomebrewFormula/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).not_to have_formula_file(relative_path)
+        end
+
+        expect(tap).to have_formula_file("kvazaar.rb")
+      ensure
+        FileUtils.rm_rf(tap.path.parent) if tap
+      end
+    end
+
+    describe "#cask_file?" do
+      it "matches files from Casks/" do
+        tap = described_class.fetch("hard/core")
+
+        %w[
+          kvazaar.rb
+          Casks/kvazaar.sh
+          Formula/kvazaar.rb
+          Formula/k/kvazaar.rb
+          HomebrewFormula/kvazaar.rb
+          HomebrewFormula/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).not_to have_cask_file(relative_path)
+        end
+
+        %w[
+          Casks/kvazaar.rb
+          Casks/k/kvazaar.rb
+        ].each do |relative_path|
+          expect(tap).to have_cask_file(relative_path)
+        end
+      end
+    end
   end
 
   describe CoreTap do