FIX: Microsoft Azure language support (#306)

We were checking if the detected language was in the key and value which would fail if the keys and values are not identical. This improves the check so "zh-Hans" (value returned by Azure) to "en" (I18n.locale) is true instead of false.

Author: nattsw

app/services/discourse_translator/provider/microsoft.rb

@@ -180,9 +180,12 @@ def self.translate_text!(text, target_locale_sym = I18n.locale)
         response_body.first["translations"].first["text"]
       end
 
-      def self.translate_supported?(detected_lang, target_lang)
-        SUPPORTED_LANG_MAPPING.keys.include?(detected_lang.to_sym) &&
-          SUPPORTED_LANG_MAPPING.values.include?(detected_lang.to_s)
+      def self.translate_supported?(detected, target)
+        s = SUPPORTED_LANG_MAPPING
+
+        # Azure language support indicates to and from language codes
+        (s.keys.include?(target.to_sym) || s.values.include?(target.to_s)) &&
+          (s.keys.include?(detected.to_sym) || s.values.include?(detected.to_s))
       end
 
       private

spec/services/microsoft_spec.rb

@@ -188,4 +188,16 @@ def detect_endpoint
       expect(described_class.translate_text!(text)).to eq(translated_text)
     end
   end
+
+  describe ".translate_supported?" do
+    it "allows translation of topics in supported languages" do
+      expect(described_class.translate_supported?(:en, "zh-Hans")).to eq(true)
+      expect(described_class.translate_supported?("en", :zh_CN)).to eq(true)
+      expect(described_class.translate_supported?("zh-Hans", :en)).to eq(true)
+      expect(described_class.translate_supported?(:zh_CN, "en")).to eq(true)
+
+      expect(described_class.translate_supported?(:tr, "en")).to eq(true)
+      expect(described_class.translate_supported?("tr", "en")).to eq(true)
+    end
+  end
 end