create test/pylink if system supports symbolic links

ruby-filemagic.gemspec

@@ -14,7 +14,7 @@ Gem::Specification.new do |s|
   s.email = "jens.wille@gmail.com".freeze
   s.extensions = ["ext/filemagic/extconf.rb".freeze]
   s.extra_rdoc_files = ["README".freeze, "ChangeLog".freeze, "ext/filemagic/filemagic.c".freeze]
-  s.files = ["CONTRIBUTING.md".freeze, "ChangeLog".freeze, "Dockerfile".freeze, "README".freeze, "Rakefile".freeze, "TODO".freeze, "ext/filemagic/extconf.rb".freeze, "ext/filemagic/filemagic.c".freeze, "ext/filemagic/filemagic.h".freeze, "lib/filemagic.rb".freeze, "lib/filemagic/ext.rb".freeze, "lib/filemagic/magic.mgc".freeze, "lib/filemagic/version.rb".freeze, "lib/ruby-filemagic.rb".freeze, "test/excel-example.xls".freeze, "test/filemagic_test.rb".freeze, "test/leaktest.rb".freeze, "test/mahoro.c".freeze, "test/perl".freeze, "test/perl.mgc".freeze, "test/pyfile".freeze, "test/pyfile-compressed.gz".freeze, "test/pylink".freeze]
+  s.files = ["CONTRIBUTING.md".freeze, "ChangeLog".freeze, "Dockerfile".freeze, "README".freeze, "Rakefile".freeze, "TODO".freeze, "ext/filemagic/extconf.rb".freeze, "ext/filemagic/filemagic.c".freeze, "ext/filemagic/filemagic.h".freeze, "lib/filemagic.rb".freeze, "lib/filemagic/ext.rb".freeze, "lib/filemagic/magic.mgc".freeze, "lib/filemagic/version.rb".freeze, "lib/ruby-filemagic.rb".freeze, "test/excel-example.xls".freeze, "test/filemagic_test.rb".freeze, "test/leaktest.rb".freeze, "test/mahoro.c".freeze, "test/perl".freeze, "test/perl.mgc".freeze, "test/pyfile".freeze, "test/pyfile-compressed.gz".freeze]
   s.homepage = "http://github.com/blackwinter/ruby-filemagic".freeze
   s.licenses = ["Ruby".freeze]
   s.post_install_message = "\nruby-filemagic-0.7.3 [2022-01-07]:\n\n* Dockerfile to build native extension (pull request #26 by Pavel Lobashov).\n* Include paths for ARM-based Apple Macs (Apple Silicon) (pull request #35 by\n  @545ch4).\n\n".freeze

test/filemagic_test.rb

@@ -24,25 +24,36 @@ def test_file
     res = fm.file(path_to('pyfile'))
     assert_equal(python_script, res)
 
-    if File.symlink?(path_to('pylink'))
-      res = fm.file(path_to('pylink'))
-      assert_equal(match_version(
-        0    => "symbolic link to `pyfile'",
-        5.22 => 'symbolic link to pyfile'
-      ), res.strip)
-    end
-
-    fm.close
-    fm = FileMagic.new(FileMagic::MAGIC_SYMLINK)
+    # The following block ensures that symlinks are only tested on systems
+    # that support them.
+    begin
+      assert(File.writable?('test'), "can't write to test directory")
+      File.symlink('pyfile', 'test/pylink')
+
+      if File.symlink?(path_to('pylink'))
+        res = fm.file(path_to('pylink'))
+        assert_equal(match_version(
+          0    => "symbolic link to `pyfile'",
+          5.22 => 'symbolic link to pyfile'
+        ), res.strip)
+      end
+
+      fm.close
+      fm = FileMagic.new(FileMagic::MAGIC_SYMLINK)
 
-    res = fm.file(path_to('pylink'))
-    assert_equal(python_script, res)
+      res = fm.file(path_to('pylink'))
+      assert_equal(python_script, res)
 
-    fm.close
-    fm = FileMagic.new(FileMagic::MAGIC_SYMLINK | FileMagic::MAGIC_MIME)
+      fm.close
+      fm = FileMagic.new(FileMagic::MAGIC_SYMLINK | FileMagic::MAGIC_MIME)
 
-    res = fm.file(path_to('pylink'))
-    assert_equal('text/plain; charset=us-ascii', res)
+      res = fm.file(path_to('pylink'))
+      assert_equal('text/plain; charset=us-ascii', res)
+    rescue NotImplementedError
+      # ignore
+    ensure
+      File.unlink('test/pylink') if File.exist?('test/pylink')
+    end
 
     fm.close
     fm = FileMagic.new(FileMagic::MAGIC_COMPRESS)
@@ -81,28 +92,39 @@ def test_descriptor
       assert_equal(python_script, res)
     }
 
-    if File.symlink?(path_to('pylink'))
+    # The following block ensures that symlinks are only tested on systems
+    # that support them.
+    begin
+      assert(File.writable?('test'), "can't write to test directory")
+      File.symlink('pyfile', 'test/pylink')
+
+      if File.symlink?(path_to('pylink'))
+        fd_for('pylink') { |fd|
+          res = fm.descriptor(fd)
+          assert_equal(python_script, res.strip)
+        }
+      end
+
+      fm.close
+      fm = FileMagic.new(FileMagic::MAGIC_SYMLINK)
+
       fd_for('pylink') { |fd|
         res = fm.descriptor(fd)
-        assert_equal(python_script, res.strip)
+        assert_equal(python_script, res)
       }
-    end
 
-    fm.close
-    fm = FileMagic.new(FileMagic::MAGIC_SYMLINK)
-
-    fd_for('pylink') { |fd|
-      res = fm.descriptor(fd)
-      assert_equal(python_script, res)
-    }
-
-    fm.close
-    fm = FileMagic.new(FileMagic::MAGIC_SYMLINK | FileMagic::MAGIC_MIME)
+      fm.close
+      fm = FileMagic.new(FileMagic::MAGIC_SYMLINK | FileMagic::MAGIC_MIME)
 
-    fd_for('pylink') { |fd|
-      res = fm.descriptor(fd)
-      assert_equal('text/plain; charset=us-ascii', res)
-    }
+      fd_for('pylink') { |fd|
+        res = fm.descriptor(fd)
+        assert_equal('text/plain; charset=us-ascii', res)
+      }
+    rescue NotImplementedError
+      # ignore
+    ensure
+      File.unlink('test/pylink') if File.exist?('test/pylink')
+    end
 
     fm.close
     fm = FileMagic.new(FileMagic::MAGIC_COMPRESS)