diff --git a/src/main/java/com/worksap/nlp/sudachi/TextNormalizer.java b/src/main/java/com/worksap/nlp/sudachi/TextNormalizer.java
index 01a67025..749fa45a 100644
--- a/src/main/java/com/worksap/nlp/sudachi/TextNormalizer.java
+++ b/src/main/java/com/worksap/nlp/sudachi/TextNormalizer.java
@@ -38,6 +38,9 @@ public class TextNormalizer {
      * {@link com.worksap.nlp.sudachi.dictionary.CharacterCategory}.
      */
     public TextNormalizer(Grammar grammar, List<InputTextPlugin> inputTextPlugins) {
+        if (grammar.getCharacterCategory() == null) {
+            throw new IllegalArgumentException("grammar for TextNormalizer must have CharacterCategory.");
+        }
         this.grammar = grammar;
         this.inputTextPlugins = inputTextPlugins;
     }
diff --git a/src/test/java/com/worksap/nlp/sudachi/TextNormalizerTest.kt b/src/test/java/com/worksap/nlp/sudachi/TextNormalizerTest.kt
new file mode 100644
index 00000000..81a7bdc9
--- /dev/null
+++ b/src/test/java/com/worksap/nlp/sudachi/TextNormalizerTest.kt
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2022 Works Applications Co., Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.worksap.nlp.sudachi
+
+import com.worksap.nlp.sudachi.dictionary.CharacterCategory
+import com.worksap.nlp.sudachi.dictionary.GrammarImpl
+import kotlin.test.*
+
+class TextNormalizerTest {
+
+  private val dic =
+      DictionaryFactory()
+          .create(TestDictionary.user2Cfg().characterDefinition(CharacterCategory.loadDefault()))
+          as JapaneseDictionary
+
+  @Test
+  fun instantiation() {
+    TextNormalizer.fromDictionary(dic)
+    TextNormalizer(dic.getGrammar())
+    TextNormalizer(dic.getGrammar(), dic.inputTextPlugins)
+    TextNormalizer.defaultTextNormalizer()
+  }
+
+  @Test
+  fun failToInstantiateWithoutCharCategory() {
+    val grammar = GrammarImpl()
+    assertFails { TextNormalizer(grammar) }
+  }
+
+  @Test
+  fun normalizeText() {
+    val tn = TextNormalizer.defaultTextNormalizer()
+
+    // from DefaultInputTextPlugin test
+    assertEquals("âbγд(株)ガヴ⼼ⅲ", tn.normalize("ÂＢΓД㈱ｶﾞウ゛⼼Ⅲ"))
+  }
+
+  @Test
+  fun normalizeTextWithDefaultConfig() {
+    // will use default config, which has InputTextPlugins of
+    // [Default, ProlongedSoundMark, IgnoreYomigana]
+    val tn = TextNormalizer.fromDictionary(dic)
+    print(dic.inputTextPlugins)
+
+    assertEquals("âbγд(株)ガヴ⼼ⅲ", tn.normalize("ÂＢΓД㈱ｶﾞウ゛⼼Ⅲ")) // default
+    assertEquals("うわーい", tn.normalize("うわーーーい")) // prolonged sound mark
+    assertEquals("小鳥遊", tn.normalize("小鳥遊（タカナシ）")) // ignore yomigana
+  }
+}