Add basic namespace tests

Author: tagomoris

test/ruby/test_namespace.rb

@@ -695,4 +695,76 @@ def test_root_and_main_methods
     pat = "_ruby_ns_*."+RbConfig::CONFIG["DLEXT"]
     File.unlink(*Dir.glob(pat, base: tmp).map {|so| "#{tmp}/#{so}"})
   end
+
+  def test_basic_namespace_detections
+    assert_separately([ENV_ENABLE_NAMESPACE], __FILE__, __LINE__, "#{<<~"begin;"}\n#{<<~'end;'}", ignore_stderr: true)
+    begin;
+      ns = Namespace.new
+      code = <<~EOC
+      NS1 = Namespace.current
+      class Foo
+        NS2 = Namespace.current
+        NS2_proc = ->(){ NS2 }
+        NS3_proc = ->(){ Namespace.current }
+
+        def ns4 = Namespace.current
+        def self.ns5 = NS2
+        def self.ns6 = Namespace.current
+        def self.ns6_proc = ->(){ Namespace.current }
+
+        def self.yield_block = yield
+        def self.call_block(&b) = b.call
+      end
+      NS9 = Foo.new.ns4
+      EOC
+      ns.eval(code)
+      outer = Namespace.current
+      assert_equal ns, ns::NS1 # on TOP frame
+      assert_equal ns, ns::Foo::NS2 # on CLASS frame
+      assert_equal ns, ns::Foo::NS2_proc.call # proc -> a const on CLASS
+      assert_equal ns, ns::Foo::NS3_proc.call # proc -> the current
+      assert_equal ns, ns::Foo.new.ns4 # instance method  -> the current
+      assert_equal ns, ns::Foo.ns5     # singleton method -> a const on CLASS
+      assert_equal ns, ns::Foo.ns6     # singleton method -> the current
+      assert_equal ns, ns::Foo.ns6_proc.call # method returns a proc -> the current
+
+      assert_equal outer, ns::Foo.yield_block{ Namespace.current } # method yields
+      assert_equal outer, ns::Foo.call_block{ Namespace.current }  # method calls a block
+      assert_equal ns, ns::NS9 # on TOP frame, referring a class in the current
+    end;
+  end
+
+  def test_loading_extension_libs_in_main_namespace
+    assert_separately([ENV_ENABLE_NAMESPACE], __FILE__, __LINE__, "#{<<~"begin;"}\n#{<<~'end;'}", ignore_stderr: true)
+    begin;
+      require "prism"
+      require "optparse"
+      require "date"
+      require "time"
+      require "delegate"
+      require "singleton"
+      require "pp"
+      require "fileutils"
+      require "tempfile"
+      require "tmpdir"
+      require "json"
+      require "psych"
+      require "yaml"
+      require "zlib"
+      require "open3"
+      require "ipaddr"
+      require "net/http"
+      require "openssl"
+      require "socket"
+      require "uri"
+      require "digest"
+      require "erb"
+      require "stringio"
+      require "monitor"
+      require "timeout"
+      require "securerandom"
+      expected = 1
+      assert_equal expected, 1
+    end;
+  end
 end