Add first unit tests to Gosu (#360)

.travis.yml

@@ -36,7 +36,7 @@ before_install:
   # Mac dependencies
   # See: https://github.com/gosu/gosu/wiki/Getting-Started-on-OS-X
   - if [ $TRAVIS_OS_NAME == osx ]; then brew update; brew install sdl2; fi
-  # Do not use RVM - it's been a mess for compiling Gosu on OS X.
+  # Do not use RVM - it's been a mess for compiling Gosu on macOS.
   - rvm use system
   # Print the Ruby configuration to see what's up with CXXFLAGS etc.
   - ruby -rrbconfig -e 'RbConfig::CONFIG.each { |k, v| puts [k, v].join("=") }'
@@ -77,7 +77,6 @@ install:
 
 script:
   # Ruby/Gosu
-  - ruby -rgosu -e 'puts RUBY_VERSION, Gosu::VERSION, Gosu::LICENSES'
-
+  - ~/rake -rgosu test
   # Compile C++ examples
   - mkdir -p examples/build && cd examples/build && cmake .. && make && cd ../..

Rakefile

@@ -2,6 +2,7 @@ require 'rubygems'
 require 'fileutils'
 require 'date'
 require 'rake/extensiontask'
+require 'rake/testtask'
 
 COMMON_FILES = FileList[
   '.yardopts',
@@ -51,3 +52,8 @@ task :update_doxygen do
   sh "ssh #{ENV['PROJECTS_HOST']} 'cd #{ENV['PROJECTS_ROOT']}/libgosu.org/ && " +
        "svn checkout https://github.com/gosu/gosu/trunk/Gosu && PATH=../doxygen/bin:$PATH doxygen'"
 end
+
+Rake::TestTask.new do |t|
+  t.test_files = FileList["test/test_*.rb"]
+  t.verbose = true
+end

appveyor.yml

@@ -21,16 +21,14 @@ build:
   verbosity: minimal
 after_build:
 - ps: >-
-    cd "$env:APPVEYOR_BUILD_FOLDER\lib"
-
-    $OLD_PATH = $env:PATH
-
     If ($env:PLATFORM -Eq "x64") {
-      $env:PATH = "C:\Ruby23-x64\bin;$OLD_PATH"
-      ruby -I. -r./gosu.rb -e "puts RUBY_VERSION, Gosu::VERSION, Gosu::LICENSES"
+      $env:PATH = "C:\Ruby23-x64\bin;$env:PATH"
+      gem install rake-compiler
+      rake -Ilib -rgosu test
     }
     Else {
-      $env:PATH = "C:\Ruby23\bin;$OLD_PATH"
-      ruby -I. -r./gosu.rb -e "puts RUBY_VERSION, Gosu::VERSION, Gosu::LICENSES"
+      $env:PATH = "C:\Ruby23\bin;$env:PATH"
+      gem install rake-compiler
+      rake -Ilib -rgosu test
     }
 test: off

test/test_constants.rb

@@ -0,0 +1,21 @@
+require "minitest/autorun"
+require "gosu" unless defined? Gosu
+
+class TestConstants < Minitest::Test
+  def test_version
+    assert_match(/\A#{Gosu::MAJOR_VERSION}.#{Gosu::MINOR_VERSION}.#{Gosu::POINT_VERSION}/,
+      Gosu::VERSION)
+  end
+
+  def test_licenses
+    assert_match(/Gosu/, Gosu::LICENSES)
+    assert_match(/SDL/, Gosu::LICENSES)
+    unless RUBY_PLATFORM =~ /darwin/
+      assert_match(/libsndfile/, Gosu::LICENSES)
+      assert_match(/OpenAL/, Gosu::LICENSES) if RUBY_PLATFORM =~ /win/
+    end
+
+    # Backward compatibility
+    assert_equal Gosu::LICENSES, Gosu::GOSU_COPYRIGHT_NOTICE
+  end
+end

test/test_interface.rb

@@ -0,0 +1,64 @@
+require "minitest/autorun"
+require "gosu" unless defined? Gosu
+
+# Make a backup of the Gosu modules and its helpers on Numeric.
+OrigGosu = Gosu
+Object.send :remove_const, :Gosu
+%w(gosu_to_radians radians_to_gosu degrees_to_radians radians_to_degrees).each do |helper|
+  Numeric.send :alias_method, :"orig_#{helper}", :"#{helper}"
+  Numeric.send :undef_method, :"#{helper}"
+end
+
+# Now load Gosu's documentation, a module that is only filled with method stubs, into GosuDocs.
+require_relative "../rdoc/gosu.rb"
+GosuDocs = Gosu
+Object.send :remove_const, :Gosu
+
+# And finally, restore the real Gosu module.
+Gosu = OrigGosu
+Object.send :remove_const, :OrigGosu
+%w(gosu_to_radians radians_to_gosu degrees_to_radians radians_to_degrees).each do |helper|
+  Numeric.send :undef_method, :"#{helper}"
+  Numeric.send :alias_method, :"#{helper}", :"orig_#{helper}"
+  Numeric.send :undef_method, :"orig_#{helper}"
+end
+
+class TestInterface < Minitest::Test
+  def test_all_constants_exist
+    GosuDocs.constants.each do |constant|
+      assert Gosu.constants.include?(constant),
+        "Expected constant Gosu::#{constant}"
+    end
+  end
+
+  def test_constant_types
+    GosuDocs.constants.each do |constant|
+      case constant
+      when /(Kb|Gp|Ms)/, /(KB_|GP_|MS_)/, /_VERSION/
+        expected_class = Integer
+      when :VERSION, :LICENSES
+        expected_class = String
+      else
+        next
+      end
+
+      assert_kind_of expected_class, Gosu.const_get(constant),
+        "Gosu::#{constant} must be #{expected_class}, is #{Gosu.const_get(constant).class}"
+    end
+  end
+
+  def test_no_extra_constants
+    Gosu.constants.each do |constant|
+      next if constant =~ /KB_|GP_|MS_/ # TODO: not yet documented
+
+      next if constant == :Button # backwards compatibility
+
+      next if constant == :ImmutableColor # implementation detail
+
+      next if constant == :MAX_TEXTURE_SIZE # not sure if we still need this :/
+
+      assert GosuDocs.constants.include?(constant),
+        "Unexpected Gosu::#{constant}"
+    end
+  end
+end