Move from Travis CI to GitHub CI (#93)

* Move from Travis CI to GitHub CI

* Update error message

* Fix Ruby 2.3 compatibility

.github/workflows/ci.yml

@@ -0,0 +1,52 @@
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ '**' ]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby:
+          - "2.3"
+          - "2.4"
+          - "2.5"
+          - "2.6"
+          - "2.7"
+          - "3.0"
+          - "jruby-9.2"
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Update apt
+        env:
+          DEBIAN_FRONTEND: noninteractive
+        run:
+          sudo apt-get update -qq -o Acquire::Retries=3
+
+      - name: Install ImageMagick
+        env:
+          DEBIAN_FRONTEND: noninteractive
+        run:
+          sudo apt-get install -qq -o Acquire::Retries=3 imagemagick graphicsmagick
+
+      - name: Install libvips
+        env:
+          DEBIAN_FRONTEND: noninteractive
+        run:
+          sudo apt-get install --fix-missing -qq -o Acquire::Retries=3 libvips
+
+      - name: Run tests
+        run: bundle exec rake test

lib/image_processing/chainable.rb

@@ -53,7 +53,9 @@ def operation(name, *args, &block)
     # Call the defined processing and get the result. Allows specifying
     # the source file and destination.
     def call(file = nil, destination: nil, **call_options)
-      options = { source: file, destination: destination }.compact
+      options = {}
+      options[:source] = file if file
+      options[:destination] = destination if destination
 
       branch(**options).call!(**call_options)
     end

test/vips_test.rb

@@ -115,7 +115,7 @@
 
   it "raises correct Vips::Error on unknown saver" do
     error = assert_raises(Vips::Error) { ImageProcessing::Vips.convert("foo").call(@portrait) }
-    assert_includes error.message, "No known saver"
+    assert_includes error.message, "is not a known file format"
   end
 
   it "accepts :saver" do