Update Ruby versions on Travis CI

.travis.yml

@@ -1,9 +1,7 @@
-# before_install:
-#   - gem update --system '2.4.5'
 language: ruby
+cache: bundler
 rvm:
-  - 2.0.0
-  - 2.1.10
-  - 2.2.5
-  - 2.3.3
-  - 2.4.0
+  - 2.4
+  - 2.5
+  - 2.6
+  - 2.7

lib/memfs.rb

@@ -25,6 +25,14 @@ module MemFs
   # Keeps track of the original Ruby IO class.
   OriginalIO = ::IO
 
+  def self.ruby_version_gte?(version) # :nodoc:
+    Gem::Version.new(RUBY_VERSION) >= Gem::Version.new(version)
+  end
+
+  def self.windows?
+    /mswin|bccwin|mingw/ =~ RUBY_PLATFORM
+  end
+
   require 'memfs/file_system'
   require 'memfs/dir'
   require 'memfs/file'

lib/memfs/dir.rb

@@ -17,6 +17,12 @@ def self.chdir(path, &block)
       0
     end
 
+    if MemFs.ruby_version_gte?('2.6')
+      def self.children(dirname, _opts = {})
+        entries(dirname, _opts) - %w[. ..]
+      end
+    end
+
     def self.chroot(path)
       fail Errno::EPERM, path unless Process.uid.zero?
 

spec/fileutils_spec.rb

@@ -20,8 +20,14 @@
       expect(described_class.pwd).to eq('/test')
     end
 
-    it 'returns nil' do
-      expect(described_class.cd('/test')).to be_nil
+    if MemFs.ruby_version_gte?('2.6')
+      it 'returns 0' do
+        expect(described_class.cd('/test')).to eq 0
+      end
+    else
+      it 'returns nil' do
+        expect(described_class.cd('/test')).to be_nil
+      end
     end
 
     it "raises an error when the given path doesn't exist" do

spec/memfs/dir_spec.rb

@@ -54,6 +54,22 @@ module MemFs
       end
     end
 
+    if MemFs.ruby_version_gte?('2.6')
+      describe '.children' do
+        it 'returns an array containing all of the filenames except for "." and ".." in this directory.' do
+          %w[/test/dir1 /test/dir2].each { |dir| described_class.mkdir dir }
+          _fs.touch '/test/file1', '/test/file2'
+          expect(described_class.children('/test')).to eq(%w[dir1 dir2 file1 file2])
+        end
+      end
+    else
+      describe '.children' do
+        it 'raises an error' do
+          expect { described_class.children('/test') }.to raise_error(NoMethodError)
+        end
+      end
+    end
+
     describe '.chroot' do
       before { allow(Process).to receive_messages(uid: 0) }
 

spec/memfs/file_spec.rb

@@ -527,9 +527,16 @@ module MemFs
       end
 
       context 'when the period is the last character in path' do
-        it 'returns an empty string' do
-          extname = described_class.extname('test-subject.')
-          expect(extname).to eq ''
+        if MemFs.ruby_version_gte?('2.7') && !MemFs.windows?
+          it 'returns a period' do
+            extname = described_class.extname('test-subject.')
+            expect(extname).to eq '.'
+          end
+        else
+          it 'returns an empty string' do
+            extname = described_class.extname('test-subject.')
+            expect(extname).to eq ''
+          end
         end
       end
     end