Add test for null

Author: emmyzhou-db

databricks-sdk-java/src/main/java/com/databricks/sdk/core/oauth/IDToken.java

@@ -15,11 +15,16 @@ public class IDToken {
    */
   public IDToken(String value) {
     if (value == null || value.isEmpty()) {
-        throw new IllegalArgumentException("ID Token value cannot be null or empty");
+      throw new IllegalArgumentException("ID Token value cannot be null or empty");
     }
     this.value = value;
   }
 
+  /**
+   * Returns the value of the ID Token.
+   *
+   * @return The string representation of the ID Token.
+   */
   public String getValue() {
     return value;
   }

databricks-sdk-java/src/test/java/com/databricks/sdk/core/oauth/IDTokenTest.java

@@ -1,6 +1,7 @@
 package com.databricks.sdk.core.oauth;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
@@ -9,8 +10,13 @@ public class IDTokenTest {
   private static final String accessToken = "testIdToken";
 
   @Test
-  void createIDToken() {
+  void testIDTokenWithValue() {
     IDToken idToken = new IDToken(accessToken);
     assertEquals(accessToken, idToken.getValue());
   }
+
+  @Test
+  void testIDTokenWithNullValue() {
+    assertThrows(IllegalArgumentException.class, () -> new IDToken(null));
+  }
 }