lib/util: add several utils from jptools

test/util/romaji_transliteration_test.dart

@@ -0,0 +1,66 @@
+import 'package:jadb/util/romaji_transliteration.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group("Romaji -> Hiragana", () {
+    test("Basic test", () {
+      final result = transliterateLatinToHiragana("katamari");
+      expect(result, "かたまり");
+    });
+
+    test("Basic test with diacritics", () {
+      final result = transliterateLatinToHiragana("gadamari");
+      expect(result, "がだまり");
+    });
+
+    test("wi and we", () {
+      final result = transliterateLatinToHiragana("wiwe");
+      expect(result, "うぃうぇ");
+    });
+
+    test("nb = mb", () {
+      final result = transliterateLatinToHiragana("kanpai");
+      expect(result, "かんぱい");
+
+      final result2 = transliterateLatinToHiragana("kampai");
+      expect(result2, "かんぱい");
+    });
+
+    test("Double n", () {
+      final result = transliterateLatinToHiragana("konnichiha");
+      expect(result, "こんにちは");
+    });
+
+    test("Double consonant", () {
+      final result = transliterateLatinToHiragana("kappa");
+      expect(result, "かっぱ");
+    });
+  });
+
+  group("Hiragana -> Romaji", () {
+    test("Basic test", () {
+      final result = transliterateHiraganaToLatin("かたまり");
+      expect(result, "katamari");
+    });
+
+    test("Basic test with diacritics", () {
+      final result = transliterateHiraganaToLatin("がだまり");
+      expect(result, "gadamari");
+    });
+
+    test("whi and whe", () {
+      final result = transliterateHiraganaToLatin("うぃうぇ");
+      expect(result, "whiwhe");
+    });
+
+    test("Double n", () {
+      final result = transliterateHiraganaToLatin("こんにちは");
+      expect(result, "konnichiha");
+    });
+
+    test("Double consonant", () {
+      final result = transliterateHiraganaToLatin("かっぱ");
+      expect(result, "kappa");
+    });
+  });
+}