diff --git a/types/umzug/index.d.ts b/types/umzug/index.d.ts
index 9f2602f361..931434aea3 100644
--- a/types/umzug/index.d.ts
+++ b/types/umzug/index.d.ts
@@ -202,9 +202,9 @@ declare namespace umzug {
         down(migrations?: string[]): Promise<Migration[]>;
         down(options?: DownToOptions | UpDownMigrationsOptions): Promise<Migration[]>;
 
-        on(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: string) => void): this;
-        addListener(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: string) => void): this;
-        removeListener(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: string) => void): this;
+        on(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: Migration) => void): this;
+        addListener(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: Migration) => void): this;
+        removeListener(eventName: 'migrating' | 'reverting' | 'migrated' | 'reverted', cb?: (name: string, migration: Migration) => void): this;
 
     }
 
diff --git a/types/umzug/umzug-tests.ts b/types/umzug/umzug-tests.ts
index b5def394e9..fad7b11427 100644
--- a/types/umzug/umzug-tests.ts
+++ b/types/umzug/umzug-tests.ts
@@ -1,133 +1,123 @@
-import * as Umzug from "umzug";
-import * as Sequelize from "sequelize";
+import * as Umzug from 'umzug';
+import * as Sequelize from 'sequelize';
 
-var someVar:Umzug.Umzug;
-var umzug = new Umzug({});
+let someVar: Umzug.Umzug;
+const umzug = new Umzug({});
 someVar = umzug;
 
-umzug.up().then(function (result) {
-  // do something with the result
-});
+umzug.up().then((migrations: Umzug.Migration[]) => null);
 
 umzug.execute({
   migrations: ['some-id', 'some-other-id'],
   method: 'up'
-}).then(function (migrations) {
-  // "migrations" will be an Array of all executed/reverted migrations.
+}).then((migrations: Umzug.Migration[]) => null);
+
+umzug.pending().then((migrations: Umzug.Migration[]) => null);
+
+umzug.executed().then((migrations: Umzug.Migration[]) => null);
+
+umzug.up().then((migrations: Umzug.Migration[]) => null);
+
+umzug.up({ to: '20141101203500-task' }).then((migrations: Umzug.Migration[]) => null);
+
+umzug.up({ migrations: ['20141101203500-task', '20141101203501-task-2'] }).then((migrations: Umzug.Migration[]) => null);
+
+umzug.up('20141101203500-task').then((migrations: Umzug.Migration[]) => null); // Runs just the passed migration
+umzug.up(['20141101203500-task', '20141101203501-task-2']).then((migrations: Umzug.Migration[]) => null);
+
+umzug.down().then((migrations: Umzug.Migration[]) => null);
+
+umzug.down({ to: '20141031080000-task' }).then((migrations: Umzug.Migration[]) => null);
+
+umzug.down({ migrations: ['20141101203500-task', '20141101203501-task-2'] }).then((migrations: Umzug.Migration[]) => null);
+
+umzug.down('20141101203500-task').then((migrations: Umzug.Migration[]) => null);
+umzug.down(['20141101203500-task', '20141101203501-task-2']).then((migrations: Umzug.Migration[]) => null);
+
+umzug.down({ to: 0 }).then((migrations: Umzug.Migration[]) => null);
+
+umzug.on('migrating', (name: string, migration: Umzug.Migration) => null);
+umzug.on('migrated', (name: string, migration: Umzug.Migration) => null);
+umzug.on('reverting', (name: string, migration: Umzug.Migration) => null);
+umzug.on('reverted', (name: string, migration: Umzug.Migration) => null);
+
+
+new Umzug({
+    // The storage.
+    // Possible values: 'json', 'sequelize', an object
+    storage: 'json',
+
+    // The options for the storage.
+    // Check the available storages for further details.
+    storageOptions: {},
+
+    // The logging function.
+    // A function that gets executed every time migrations start and have ended.
+    logging: false,
+
+    // The name of the positive method in migrations.
+    upName: 'up',
+
+    // The name of the negative method in migrations.
+    downName: 'down',
+
+    migrations: {
+        // The params that gets passed to the migrations.
+        // Might be an array or a synchronous function which returns an array.
+        params: [],
+
+        // The path to the migrations directory.
+        path: 'migrations',
+
+        // The pattern that determines whether or not a file is a migration.
+        pattern: /^\d+[\w-]+\.js$/,
+
+        // A function that receives and returns the to be executed function.
+        // This can be used to modify the function.
+        wrap: <T> (fun: T) => fun,
+    },
 });
 
-umzug.pending().then(function (migrations) {
-  // "migrations" will be an Array with the names of
-  // pending migrations.
+new Umzug({
+    // The storage.
+    // Possible values: 'json', 'sequelize', an object
+    storage: 'json',
+    storageOptions: {
+        path: '/db/sequelize-meta.json',
+    },
 });
 
-umzug.executed().then(function (migrations) {
-  // "migrations" will be an Array of already executed migrations.
-});
+const sequelize = new Sequelize('');
 
-umzug.up().then(function (migrations) {
-  // "migrations" will be an Array with the names of the
-  // executed migrations.
-});
+new Umzug({
+    // The storage.
+    // Possible values: 'json', 'sequelize', an object
+    storage: 'sequelize',
+    storageOptions: {
+        // The configured instance of Sequelize.
+        // Optional if `model` is passed.
+        sequelize: sequelize,
 
-umzug.up({ to: '20141101203500-task' }).then(function (migrations) {});
+        // The to be used Sequelize model.
+        // Must have column name matching `columnName` option
+        // Optional of `sequelize` is passed.
+        model: sequelize.define<any, any>('model', {}),
 
-umzug.up({ migrations: ['20141101203500-task', '20141101203501-task-2'] });
+        // The name of the to be used model.
+        // Defaults to 'SequelizeMeta'
+        modelName: 'Schema',
 
-umzug.up('20141101203500-task'); // Runs just the passed migration
-umzug.up(['20141101203500-task', '20141101203501-task-2']);
+        // The name of table to create if `model` option is not supplied
+        // Defaults to `modelName`
+        tableName: 'Schema',
 
-umzug.down().then(function (migration) {
-  // "migration" will the name of the reverted migration.
-});
+        // The name of table column holding migration name.
+        // Defaults to 'name'.
+        columnName: 'migration',
 
-umzug.down({ to: '20141031080000-task' }).then(function (migrations) {
-  // "migrations" will be an Array with the names of all reverted migrations.
-});
-
-umzug.down({ migrations: ['20141101203500-task', '20141101203501-task-2'] });
-
-umzug.down('20141101203500-task'); // Runs just the passed migration
-umzug.down(['20141101203500-task', '20141101203501-task-2']);
-
-umzug.down({to: 0}); // Reverts every migration. 
-
-var AnotherUmzug = new Umzug({
-  // The storage.
-  // Possible values: 'json', 'sequelize', an object
-  storage: 'json',
-
-  // The options for the storage.
-  // Check the available storages for further details.
-  storageOptions: {},
-
-  // The logging function.
-  // A function that gets executed everytime migrations start and have ended.
-  logging: false,
-
-  // The name of the positive method in migrations.
-  upName: 'up',
-
-  // The name of the negative method in migrations.
-  downName: 'down',
-
-  migrations: {
-    // The params that gets passed to the migrations.
-    // Might be an array or a synchronous function which returns an array.
-    params: [],
-
-    // The path to the migrations directory.
-    path: 'migrations',
-
-    // The pattern that determines whether or not a file is a migration.
-    pattern: /^\d+[\w-]+\.js$/,
-
-    // A function that receives and returns the to be executed function.
-    // This can be used to modify the function.
-    wrap: <T>(fun: T) => fun,
-  }
-});
-
-var AnotherUmzug = new Umzug({
-  // The storage.
-  // Possible values: 'json', 'sequelize', an object
-  storage: 'json',
-  storageOptions: {
-      path: '/db/sequelize-meta.json'
-  }
-});
-
-var sequelize = new Sequelize('');
-
-var AnotherUmzug = new Umzug({
-  // The storage.
-  // Possible values: 'json', 'sequelize', an object
-  storage: 'sequelize',
-  storageOptions: {
-    // The configured instance of Sequelize.
-    // Optional if `model` is passed.
-    sequelize: sequelize,
-
-    // The to be used Sequelize model.
-    // Must have column name matching `columnName` option
-    // Optional of `sequelize` is passed.
-    model: sequelize.define<any, any>( 'model', {} ),
-
-    // The name of the to be used model.
-    // Defaults to 'SequelizeMeta'
-    modelName: 'Schema',
-
-    // The name of table to create if `model` option is not supplied
-    // Defaults to `modelName`
-    tableName: 'Schema',
-
-    // The name of table column holding migration name.
-    // Defaults to 'name'.
-    columnName: 'migration',
-
-    // The type of the column holding migration name.
-    // Defaults to `Sequelize.STRING`
-    columnType: Sequelize.STRING(100)
-  }
+        // The type of the column holding migration name.
+        // Defaults to `Sequelize.STRING`
+        columnType: Sequelize.STRING(100),
+    },
 
 });