Add spec tests for Wikipedia inline macro

spec/wikipedia_inline_macro_spec.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+describe WikipediaInlineMacro do
+  it 'should link to the Wikipedia page for Diff' do
+    input = 'wikipedia:Diff[]'
+
+    expected = <<~RESULT
+      <a href="https://en.wikipedia.org/wiki/Diff">Diff</a>
+    RESULT
+
+    actual = (Asciidoctor.convert input).tr_s '\n', '\n'
+    (expect actual).to include expected.chomp
+  end
+
+  it 'should link to the Japanese Wikipedia page for Diff' do
+    input = 'wikipedia:Diff[lang=ja]'
+
+    expected = <<~RESULT
+      <a href="https://ja.wikipedia.org/wiki/Diff">Diff</a>
+    RESULT
+
+    actual = (Asciidoctor.convert input).tr_s '\n', '\n'
+    (expect actual).to include expected.chomp
+  end
+
+  it 'should link to the Japanese Wikipedia page for Diff but with replaced captions' do
+    input = 'wikipedia:Diff[diff in Japanese Wikipedia, lang=ja]'
+
+    expected = <<~RESULT
+      <a href="https://ja.wikipedia.org/wiki/Diff">diff in Japanese Wikipedia</a>
+    RESULT
+
+    actual = (Asciidoctor.convert input).tr_s '\n', '\n'
+    (expect actual).to include expected.chomp
+  end
+
+  it 'should link to the Simple English Wikipedia page for photosynthesis' do
+    input = 'wikipedia:Photosynthesis[lang=simple]'
+
+    expected = <<~RESULT
+      <a href="https://simple.wikipedia.org/wiki/Photosynthesis">Photosynthesis</a>
+    RESULT
+
+    actual = (Asciidoctor.convert input).tr_s '\n', '\n'
+    (expect actual).to include expected.chomp
+  end
+end