diff --git a/services/identity/src/database.rs b/services/identity/src/database.rs
index cd6e6ee7b..320e340db 100644
--- a/services/identity/src/database.rs
+++ b/services/identity/src/database.rs
@@ -1,829 +1,840 @@
 use std::collections::HashMap;
 use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::str::FromStr;
 use std::sync::Arc;
 
 use aws_config::SdkConfig;
 use aws_sdk_dynamodb::model::AttributeValue;
 use aws_sdk_dynamodb::output::{
   DeleteItemOutput, GetItemOutput, PutItemOutput, QueryOutput, UpdateItemOutput,
 };
 use aws_sdk_dynamodb::types::Blob;
 use aws_sdk_dynamodb::{Client, Error as DynamoDBError};
 use chrono::{DateTime, Utc};
 use opaque_ke::{errors::ProtocolError, ServerRegistration};
 use serde::{Deserialize, Serialize};
 use tracing::{debug, error, info, warn};
 
 use crate::config::CONFIG;
 use crate::constants::{
   ACCESS_TOKEN_SORT_KEY, ACCESS_TOKEN_TABLE,
   ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE, ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
   ACCESS_TOKEN_TABLE_PARTITION_KEY, ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
   ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE, NONCE_TABLE,
   NONCE_TABLE_CREATED_ATTRIBUTE, NONCE_TABLE_PARTITION_KEY, USERS_TABLE,
   USERS_TABLE_DEVICES_ATTRIBUTE, USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME,
   USERS_TABLE_DEVICE_ATTRIBUTE_NAME, USERS_TABLE_INITIALIZATION_INFO,
   USERS_TABLE_PARTITION_KEY, USERS_TABLE_REGISTRATION_ATTRIBUTE,
   USERS_TABLE_USERNAME_ATTRIBUTE, USERS_TABLE_USERNAME_INDEX,
   USERS_TABLE_WALLET_ADDRESS_ATTRIBUTE, USERS_TABLE_WALLET_ADDRESS_INDEX,
 };
 use crate::nonce::NonceData;
 use crate::token::{AccessTokenData, AuthType};
 use comm_opaque::Cipher;
 
 #[derive(Serialize, Deserialize)]
 pub struct OlmKeys {
   curve25519: String,
   ed25519: String,
 }
 
 #[derive(Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct KeyPayload {
   pub notification_identity_public_keys: OlmKeys,
   pub primary_identity_public_keys: OlmKeys,
 }
 
 impl FromStr for KeyPayload {
   type Err = serde_json::Error;
 
   // The payload is held in the database as an escaped JSON payload.
   // Escaped double quotes need to be trimmed before attempting to serialize
   fn from_str(payload: &str) -> Result<KeyPayload, Self::Err> {
     serde_json::from_str(&payload.replace(r#"\""#, r#"""#))
   }
 }
 
 #[derive(Clone)]
 pub struct DatabaseClient {
   client: Arc<Client>,
 }
 
 impl DatabaseClient {
   pub fn new(aws_config: &SdkConfig) -> Self {
     let client = match &CONFIG.localstack_endpoint {
       Some(endpoint) => {
         info!(
           "Configuring DynamoDB client to use LocalStack endpoint: {}",
           endpoint
         );
         let ddb_config_builder =
           aws_sdk_dynamodb::config::Builder::from(aws_config)
             .endpoint_url(endpoint);
         Client::from_conf(ddb_config_builder.build())
       }
       None => Client::new(aws_config),
     };
 
     DatabaseClient {
       client: Arc::new(client),
     }
   }
 
   pub async fn get_pake_registration(
     &self,
     user_id: String,
   ) -> Result<Option<ServerRegistration<Cipher>>, Error> {
     match self.get_item_from_users_table(&user_id).await {
       Ok(GetItemOutput {
         item: Some(mut item),
         ..
       }) => parse_registration_data_attribute(
         item.remove(USERS_TABLE_REGISTRATION_ATTRIBUTE),
       )
       .map(Some)
       .map_err(Error::Attribute),
       Ok(_) => {
         info!(
           "No item found for user {} in PAKE registration table",
           user_id
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get registration data for user {}: {}",
           user_id, e
         );
         Err(e)
       }
     }
   }
 
   pub async fn get_session_initialization_info(
     &self,
     user_id: &str,
   ) -> Result<Option<HashMap<String, HashMap<String, String>>>, Error> {
     match self.get_item_from_users_table(user_id).await {
       Ok(GetItemOutput {
         item: Some(mut item),
         ..
       }) => parse_devices_attribute(item.remove(USERS_TABLE_DEVICES_ATTRIBUTE))
         .map(Some)
         .map_err(Error::Attribute),
       Ok(_) => {
         info!("No item found for user {} in users table", user_id);
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get session initialization info for user {}: {}",
           user_id, e
         );
         Err(e)
       }
     }
   }
 
   pub async fn update_users_table(
     &self,
     user_id: String,
     signing_public_key: Option<String>,
     registration: Option<ServerRegistration<Cipher>>,
     username: Option<String>,
     session_initialization_info: Option<&HashMap<String, String>>,
   ) -> Result<UpdateItemOutput, Error> {
     let mut update_expression_parts = Vec::new();
     let mut expression_attribute_names = HashMap::new();
     let mut expression_attribute_values = HashMap::new();
     if let Some(reg) = registration {
       update_expression_parts
         .push(format!("{} = :r", USERS_TABLE_REGISTRATION_ATTRIBUTE));
       expression_attribute_values.insert(
         ":r".to_string(),
         AttributeValue::B(Blob::new(reg.serialize())),
       );
     };
     if let Some(username) = username {
       update_expression_parts
         .push(format!("{} = :u", USERS_TABLE_USERNAME_ATTRIBUTE));
       expression_attribute_values
         .insert(":u".to_string(), AttributeValue::S(username));
     };
     if let Some(public_key) = signing_public_key {
       let device_info = match session_initialization_info {
         Some(info) => info
           .iter()
           .map(|(k, v)| (k.to_string(), AttributeValue::S(v.to_string())))
           .collect(),
         None => HashMap::new(),
       };
 
       // How we construct the update expression will depend on whether the user
       // already exists or not
       if let GetItemOutput { item: Some(_), .. } =
         self.get_item_from_users_table(&user_id).await?
       {
         update_expression_parts.push(format!(
           "{}.#{} = :k",
           USERS_TABLE_DEVICES_ATTRIBUTE, USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME,
         ));
         expression_attribute_names.insert(
           format!("#{}", USERS_TABLE_DEVICES_MAP_ATTRIBUTE_NAME),
           public_key,
         );
         expression_attribute_values
           .insert(":k".to_string(), AttributeValue::M(device_info));
       } else {
         update_expression_parts
           .push(format!("{} = :k", USERS_TABLE_DEVICES_ATTRIBUTE));
         let mut devices = HashMap::new();
         devices.insert(public_key, AttributeValue::M(device_info));
         expression_attribute_values
           .insert(":k".to_string(), AttributeValue::M(devices));
       };
     };
 
     self
       .client
       .update_item()
       .table_name(USERS_TABLE)
       .key(USERS_TABLE_PARTITION_KEY, AttributeValue::S(user_id))
       .update_expression(format!("SET {}", update_expression_parts.join(",")))
       .set_expression_attribute_names(
         if expression_attribute_names.is_empty() {
           None
         } else {
           Some(expression_attribute_names)
         },
       )
       .set_expression_attribute_values(
         if expression_attribute_values.is_empty() {
           None
         } else {
           Some(expression_attribute_values)
         },
       )
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn add_user_to_users_table(
     &self,
     user_id: String,
     registration: ServerRegistration<Cipher>,
     username: String,
     signing_public_key: String,
     session_initialization_info: &HashMap<String, String>,
   ) -> Result<PutItemOutput, Error> {
     let device_info: HashMap<String, AttributeValue> =
       session_initialization_info
         .iter()
         .map(|(k, v)| (k.to_string(), AttributeValue::S(v.to_string())))
         .collect();
 
     let item = HashMap::from([
       (
         USERS_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(user_id),
       ),
       (
         USERS_TABLE_USERNAME_ATTRIBUTE.to_string(),
         AttributeValue::S(username),
       ),
       (
         USERS_TABLE_REGISTRATION_ATTRIBUTE.to_string(),
         AttributeValue::B(Blob::new(registration.serialize())),
       ),
       (
         USERS_TABLE_DEVICES_ATTRIBUTE.to_string(),
         AttributeValue::M(HashMap::from([(
           signing_public_key,
           AttributeValue::M(device_info),
         )])),
       ),
     ]);
 
     self
       .client
       .put_item()
       .table_name(USERS_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn delete_user(
     &self,
     user_id: String,
   ) -> Result<DeleteItemOutput, Error> {
     debug!("Attempting to delete user: {}", user_id);
 
     match self
       .client
       .delete_item()
       .table_name(USERS_TABLE)
       .key(
         USERS_TABLE_PARTITION_KEY,
         AttributeValue::S(user_id.clone()),
       )
       .send()
       .await
     {
       Ok(out) => {
         info!("User has been deleted {}", user_id);
         Ok(out)
       }
       Err(e) => {
         error!("DynamoDB client failed to delete user {}", user_id);
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn get_access_token_data(
     &self,
     user_id: String,
     signing_public_key: String,
   ) -> Result<Option<AccessTokenData>, Error> {
     let primary_key = create_composite_primary_key(
       (
         ACCESS_TOKEN_TABLE_PARTITION_KEY.to_string(),
         user_id.clone(),
       ),
       (
         ACCESS_TOKEN_SORT_KEY.to_string(),
         signing_public_key.clone(),
       ),
     );
     let get_item_result = self
       .client
       .get_item()
       .table_name(ACCESS_TOKEN_TABLE)
       .set_key(Some(primary_key))
       .consistent_read(true)
       .send()
       .await;
     match get_item_result {
       Ok(GetItemOutput {
         item: Some(mut item),
         ..
       }) => {
         let created = parse_created_attribute(
           item.remove(ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE),
         )?;
         let auth_type = parse_auth_type_attribute(
           item.remove(ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE),
         )?;
         let valid = parse_valid_attribute(
           item.remove(ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE),
         )?;
         let access_token = parse_token_attribute(
           item.remove(ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE),
         )?;
         Ok(Some(AccessTokenData {
           user_id,
           signing_public_key,
           access_token,
           created,
           auth_type,
           valid,
         }))
       }
       Ok(_) => {
         info!(
           "No item found for user {} and signing public key {} in token table",
           user_id, signing_public_key
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get token for user {} with signing public key {}: {}",
           user_id, signing_public_key, e
         );
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn put_access_token_data(
     &self,
     access_token_data: AccessTokenData,
   ) -> Result<PutItemOutput, Error> {
     let item = HashMap::from([
       (
         ACCESS_TOKEN_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(access_token_data.user_id),
       ),
       (
         ACCESS_TOKEN_SORT_KEY.to_string(),
         AttributeValue::S(access_token_data.signing_public_key),
       ),
       (
         ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE.to_string(),
         AttributeValue::S(access_token_data.access_token),
       ),
       (
         ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE.to_string(),
         AttributeValue::S(access_token_data.created.to_rfc3339()),
       ),
       (
         ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE.to_string(),
         AttributeValue::S(match access_token_data.auth_type {
           AuthType::Password => "password".to_string(),
           AuthType::Wallet => "wallet".to_string(),
         }),
       ),
       (
         ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE.to_string(),
         AttributeValue::Bool(access_token_data.valid),
       ),
     ]);
     self
       .client
       .put_item()
       .table_name(ACCESS_TOKEN_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
+  pub async fn username_available(
+    &self,
+    username: String,
+  ) -> Result<bool, Error> {
+    let result = self
+      .get_user_id_from_user_info(username, AuthType::Password)
+      .await?;
+
+    Ok(result.is_none())
+  }
+
   pub async fn get_user_id_from_user_info(
     &self,
     user_info: String,
     auth_type: AuthType,
   ) -> Result<Option<String>, Error> {
     let (index, attribute_name) = match auth_type {
       AuthType::Password => {
         (USERS_TABLE_USERNAME_INDEX, USERS_TABLE_USERNAME_ATTRIBUTE)
       }
       AuthType::Wallet => (
         USERS_TABLE_WALLET_ADDRESS_INDEX,
         USERS_TABLE_WALLET_ADDRESS_ATTRIBUTE,
       ),
     };
     match self
       .client
       .query()
       .table_name(USERS_TABLE)
       .index_name(index)
       .key_condition_expression(format!("{} = :u", attribute_name))
       .expression_attribute_values(":u", AttributeValue::S(user_info.clone()))
       .send()
       .await
     {
       Ok(QueryOutput {
         items: Some(mut items),
         ..
       }) => {
         let num_items = items.len();
         if num_items == 0 {
           return Ok(None);
         }
         if num_items > 1 {
           warn!(
             "{} user IDs associated with {} {}: {:?}",
             num_items, attribute_name, user_info, items
           );
         }
         parse_string_attribute(
           USERS_TABLE_PARTITION_KEY,
           items[0].remove(USERS_TABLE_PARTITION_KEY),
         )
         .map(Some)
         .map_err(Error::Attribute)
       }
       Ok(_) => {
         info!(
           "No item found for {} {} in users table",
           attribute_name, user_info
         );
         Ok(None)
       }
       Err(e) => {
         error!(
           "DynamoDB client failed to get user ID from {} {}: {}",
           attribute_name, user_info, e
         );
         Err(Error::AwsSdk(e.into()))
       }
     }
   }
 
   pub async fn get_item_from_users_table(
     &self,
     user_id: &str,
   ) -> Result<GetItemOutput, Error> {
     let primary_key = create_simple_primary_key((
       USERS_TABLE_PARTITION_KEY.to_string(),
       user_id.to_string(),
     ));
     self
       .client
       .get_item()
       .table_name(USERS_TABLE)
       .set_key(Some(primary_key))
       .consistent_read(true)
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 
   pub async fn get_users(&self) -> Result<Vec<String>, Error> {
     let scan_output = self
       .client
       .scan()
       .table_name(USERS_TABLE)
       .projection_expression(USERS_TABLE_PARTITION_KEY)
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))?;
 
     let mut result = Vec::new();
     if let Some(attributes) = scan_output.items {
       for mut attribute in attributes {
         let id = parse_string_attribute(
           USERS_TABLE_PARTITION_KEY,
           attribute.remove(USERS_TABLE_PARTITION_KEY),
         )
         .map_err(Error::Attribute)?;
         result.push(id);
       }
     }
     Ok(result)
   }
 
   pub async fn add_nonce_to_nonces_table(
     &self,
     nonce_data: NonceData,
   ) -> Result<PutItemOutput, Error> {
     let item = HashMap::from([
       (
         NONCE_TABLE_PARTITION_KEY.to_string(),
         AttributeValue::S(nonce_data.nonce),
       ),
       (
         NONCE_TABLE_CREATED_ATTRIBUTE.to_string(),
         AttributeValue::S(nonce_data.created.to_rfc3339()),
       ),
     ]);
     self
       .client
       .put_item()
       .table_name(NONCE_TABLE)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| Error::AwsSdk(e.into()))
   }
 }
 
 #[derive(
   Debug, derive_more::Display, derive_more::From, derive_more::Error,
 )]
 pub enum Error {
   #[display(...)]
   AwsSdk(DynamoDBError),
   #[display(...)]
   Attribute(DBItemError),
 }
 
 #[derive(Debug, derive_more::Error, derive_more::Constructor)]
 pub struct DBItemError {
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
   attribute_error: DBItemAttributeError,
 }
 
 impl Display for DBItemError {
   fn fmt(&self, f: &mut Formatter) -> FmtResult {
     match &self.attribute_error {
       DBItemAttributeError::Missing => {
         write!(f, "Attribute {} is missing", self.attribute_name)
       }
       DBItemAttributeError::IncorrectType => write!(
         f,
         "Value for attribute {} has incorrect type: {:?}",
         self.attribute_name, self.attribute_value
       ),
       error => write!(
         f,
         "Error regarding attribute {} with value {:?}: {}",
         self.attribute_name, self.attribute_value, error
       ),
     }
   }
 }
 
 #[derive(Debug, derive_more::Display, derive_more::Error)]
 pub enum DBItemAttributeError {
   #[display(...)]
   Missing,
   #[display(...)]
   IncorrectType,
   #[display(...)]
   InvalidTimestamp(chrono::ParseError),
   #[display(...)]
   Pake(ProtocolError),
 }
 
 type AttributeName = String;
 
 fn create_simple_primary_key(
   partition_key: (AttributeName, String),
 ) -> HashMap<AttributeName, AttributeValue> {
   HashMap::from([(partition_key.0, AttributeValue::S(partition_key.1))])
 }
 
 fn create_composite_primary_key(
   partition_key: (AttributeName, String),
   sort_key: (AttributeName, String),
 ) -> HashMap<AttributeName, AttributeValue> {
   let mut primary_key = create_simple_primary_key(partition_key);
   primary_key.insert(sort_key.0, AttributeValue::S(sort_key.1));
   primary_key
 }
 
 fn parse_created_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<DateTime<Utc>, DBItemError> {
   if let Some(AttributeValue::S(created)) = &attribute {
     created.parse().map_err(|e| {
       DBItemError::new(
         ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
         attribute,
         DBItemAttributeError::InvalidTimestamp(e),
       )
     })
   } else {
     Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_CREATED_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     ))
   }
 }
 
 fn parse_auth_type_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<AuthType, DBItemError> {
   if let Some(AttributeValue::S(auth_type)) = &attribute {
     match auth_type.as_str() {
       "password" => Ok(AuthType::Password),
       "wallet" => Ok(AuthType::Wallet),
       _ => Err(DBItemError::new(
         ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE,
         attribute,
         DBItemAttributeError::IncorrectType,
       )),
     }
   } else {
     Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_AUTH_TYPE_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     ))
   }
 }
 
 fn parse_valid_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<bool, DBItemError> {
   match attribute {
     Some(AttributeValue::Bool(valid)) => Ok(valid),
     Some(_) => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_VALID_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_token_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<String, DBItemError> {
   match attribute {
     Some(AttributeValue::S(token)) => Ok(token),
     Some(_) => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       ACCESS_TOKEN_TABLE_TOKEN_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_registration_data_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<ServerRegistration<Cipher>, DBItemError> {
   match &attribute {
     Some(AttributeValue::B(server_registration_bytes)) => {
       match ServerRegistration::<Cipher>::deserialize(
         server_registration_bytes.as_ref(),
       ) {
         Ok(server_registration) => Ok(server_registration),
         Err(e) => Err(DBItemError::new(
           USERS_TABLE_REGISTRATION_ATTRIBUTE,
           attribute,
           DBItemAttributeError::Pake(e),
         )),
       }
     }
     Some(_) => Err(DBItemError::new(
       USERS_TABLE_REGISTRATION_ATTRIBUTE,
       attribute,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       USERS_TABLE_REGISTRATION_ATTRIBUTE,
       attribute,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_devices_attribute(
   attribute: Option<AttributeValue>,
 ) -> Result<HashMap<String, HashMap<String, String>>, DBItemError> {
   let mut devices = HashMap::new();
   let ddb_devices =
     parse_map_attribute(USERS_TABLE_DEVICES_ATTRIBUTE, attribute)?;
 
   for (signing_public_key, session_initialization_info) in ddb_devices {
     let session_initialization_info_map = parse_map_attribute(
       USERS_TABLE_DEVICE_ATTRIBUTE_NAME,
       Some(session_initialization_info),
     )?;
     let mut inner_hash_map = HashMap::new();
     for (initialization_component_name, initialization_component_value) in
       session_initialization_info_map
     {
       let initialization_piece_value_string = parse_string_attribute(
         USERS_TABLE_INITIALIZATION_INFO,
         Some(initialization_component_value),
       )?;
       inner_hash_map.insert(
         initialization_component_name,
         initialization_piece_value_string,
       );
     }
     devices.insert(signing_public_key, inner_hash_map);
   }
   Ok(devices)
 }
 
 fn parse_map_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<HashMap<String, AttributeValue>, DBItemError> {
   match attribute_value {
     Some(AttributeValue::M(map)) => Ok(map),
     Some(_) => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_string_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<String, DBItemError> {
   match attribute_value {
     Some(AttributeValue::S(value)) => Ok(value),
     Some(_) => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 #[cfg(test)]
 mod tests {
   use super::*;
 
   #[test]
   fn test_create_simple_primary_key() {
     let partition_key_name = "userID".to_string();
     let partition_key_value = "12345".to_string();
     let partition_key =
       (partition_key_name.clone(), partition_key_value.clone());
     let mut primary_key = create_simple_primary_key(partition_key);
     assert_eq!(primary_key.len(), 1);
     let attribute = primary_key.remove(&partition_key_name);
     assert!(attribute.is_some());
     assert_eq!(attribute, Some(AttributeValue::S(partition_key_value)));
   }
 
   #[test]
   fn test_create_composite_primary_key() {
     let partition_key_name = "userID".to_string();
     let partition_key_value = "12345".to_string();
     let partition_key =
       (partition_key_name.clone(), partition_key_value.clone());
     let sort_key_name = "deviceID".to_string();
     let sort_key_value = "54321".to_string();
     let sort_key = (sort_key_name.clone(), sort_key_value.clone());
     let mut primary_key = create_composite_primary_key(partition_key, sort_key);
     assert_eq!(primary_key.len(), 2);
     let partition_key_attribute = primary_key.remove(&partition_key_name);
     assert!(partition_key_attribute.is_some());
     assert_eq!(
       partition_key_attribute,
       Some(AttributeValue::S(partition_key_value))
     );
     let sort_key_attribute = primary_key.remove(&sort_key_name);
     assert!(sort_key_attribute.is_some());
     assert_eq!(sort_key_attribute, Some(AttributeValue::S(sort_key_value)))
   }
 
   #[test]
   fn validate_keys() {
     // Taken from test user
     let example_payload = r#"{\"notificationIdentityPublicKeys\":{\"curve25519\":\"DYmV8VdkjwG/VtC8C53morogNJhpTPT/4jzW0/cxzQo\",\"ed25519\":\"D0BV2Y7Qm36VUtjwyQTJJWYAycN7aMSJmhEsRJpW2mk\"},\"primaryIdentityPublicKeys\":{\"curve25519\":\"Y4ZIqzpE1nv83kKGfvFP6rifya0itRg2hifqYtsISnk\",\"ed25519\":\"cSlL+VLLJDgtKSPlIwoCZg0h0EmHlQoJC08uV/O+jvg\"}}"#;
     let serialized_payload = KeyPayload::from_str(&example_payload).unwrap();
 
     assert_eq!(
       serialized_payload
         .notification_identity_public_keys
         .curve25519,
       "DYmV8VdkjwG/VtC8C53morogNJhpTPT/4jzW0/cxzQo"
     );
   }
 }