Make sure erb.rb in this repository is tested

Author: k0kubun

test/erb/test_erb_command.rb

@@ -4,28 +4,25 @@
 
 class TestErbCommand < Test::Unit::TestCase
   def test_var
-    pend 'this test has not supported Ruby 2.5' if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.6.0')
-    assert_in_out_err(["-w",
+    assert_in_out_err(["-I#{File.expand_path('../../lib', __dir__)}", "-w",
                        File.expand_path("../../libexec/erb", __dir__),
                        "var=hoge"],
                       "<%=var%>", ["hoge"])
   end
 
   def test_template_file_encoding
-    pend 'this test has not supported Ruby 2.5' if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.6.0')
-    assert_in_out_err(["-w",
+    assert_in_out_err(["-I#{File.expand_path('../../lib', __dir__)}", "-w",
                        File.expand_path("../../libexec/erb", __dir__)],
                       "<%=''.encoding.to_s%>", ["UTF-8"])
   end
 
   # These interfaces will be removed at Ruby 2.7.
   def test_deprecated_option
-    pend 'this test has not supported Ruby 2.5' if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.6.0')
     warnings = [
       "warning: -S option of erb command is deprecated. Please do not use this.",
       /\n.+\/libexec\/erb:\d+: warning: Passing safe_level with the 2nd argument of ERB\.new is deprecated\. Do not use it, and specify other arguments as keyword arguments\.\n/,
     ]
-    assert_in_out_err(["-w",
+    assert_in_out_err(["-I#{File.expand_path('../../lib', __dir__)}", "-w",
                        File.expand_path("../../libexec/erb", __dir__),
                        "-S", "0"],
                       "hoge", ["hoge"], warnings)