formula_assertions: use minitest

We are migrating away from using system gems, and we already have minitest in our dependency tree, so we might as well use it.

Library/Homebrew/Gemfile

@@ -6,6 +6,7 @@ source "https://rubygems.org"
 gem "bootsnap", require: false
 gem "byebug", require: false
 gem "codecov", require: false
+gem "minitest", require: false
 gem "nokogiri", require: false
 gem "parallel_tests", require: false
 gem "ronn", require: false

Library/Homebrew/Gemfile.lock

@@ -179,6 +179,7 @@ DEPENDENCIES
   codecov
   concurrent-ruby
   mechanize
+  minitest
   nokogiri
   parallel_tests
   patchelf

Library/Homebrew/dev-cmd/test.rb

@@ -35,6 +35,8 @@ module Homebrew
   def test
     args = test_args.parse
 
+    Homebrew.install_bundler_gems!
+
     require "formula_assertions"
     require "formula_free_port"
 

Library/Homebrew/formula_assertions.rb

@@ -8,8 +8,38 @@ module Homebrew
   module Assertions
     include Context
 
-    require "test/unit/assertions"
-    include ::Test::Unit::Assertions
+    require "minitest"
+    require "minitest/assertions"
+    include ::Minitest::Assertions
+
+    attr_writer :assertions
+
+    def assertions
+      @assertions ||= 0
+    end
+
+    # Test::Unit backwards compatibility methods
+    {
+      assert_raise:           :assert_raises,
+      assert_not_empty:       :refute_empty,
+      assert_not_equal:       :refute_equal,
+      assert_not_in_delta:    :refute_in_delta,
+      assert_not_in_epsilon:  :refute_in_epsilon,
+      assert_not_includes:    :refute_includes,
+      assert_not_instance_of: :refute_instance_of,
+      assert_not_kind_of:     :refute_kind_of,
+      assert_no_match:        :refute_match,
+      assert_not_nil:         :refute_nil,
+      assert_not_operator:    :refute_operator,
+      assert_not_predicate:   :refute_predicate,
+      assert_not_respond_to:  :refute_respond_to,
+      assert_not_same:        :refute_same,
+    }.each do |old_method, new_method|
+      define_method(old_method) do |*args|
+        # odeprecated old_method, new_method
+        send(new_method, *args)
+      end
+    end
 
     # Returns the output of running cmd, and asserts the exit status.
     # @api public
@@ -18,7 +48,7 @@ module Homebrew
       output = `#{cmd}`
       assert_equal result, $CHILD_STATUS.exitstatus
       output
-    rescue Test::Unit::AssertionFailedError
+    rescue Minitest::Assertion
       puts output if verbose?
       raise
     end
@@ -35,7 +65,7 @@ module Homebrew
       end
       assert_equal result, $CHILD_STATUS.exitstatus unless result.nil?
       output
-    rescue Test::Unit::AssertionFailedError
+    rescue Minitest::Assertion
       puts output if verbose?
       raise
     end