diff --git a/src/actions.test.js b/src/actions.test.js
deleted file mode 100644
index 8c35f98..0000000
--- a/src/actions.test.js
+++ /dev/null
@@ -1,38 +0,0 @@
-import updux from '.';
-import u from 'updeep';
-
-test( 'actions defined in effects and mutations, multi-level', () => {
-
-    const { actions } = updux({
-        effects: {
-            foo: api => next => action => { },
-        },
-        mutations: { bar: () => () => null },
-        subduxes: {
-            mysub: {
-                effects: { baz: api => next => action => { }, },
-                mutations: { quux: () => () => null },
-                actions: {
-                    foo: (limit) => ({limit}),
-                },
-            },
-            myothersub: {
-                effects: {
-                    foo: () => () => () => {},
-                },
-            }
-        },
-    });
-
-    const types = Object.keys(actions);
-    types.sort();
-
-    expect( types).toEqual([ 'bar', 'baz', 'foo', 'quux', ]);
-
-    expect( actions.bar() ).toEqual({ type: 'bar' });
-    expect( actions.bar('xxx') ).toEqual({ type: 'bar', payload: 'xxx' });
-    expect( actions.bar(undefined,'yyy') ).toEqual({ type: 'bar',meta: 'yyy' });
-
-    expect(actions.foo(12)).toEqual({type: 'foo', payload: { limit: 12 }});
-
-});
diff --git a/src/actions.test.ts b/src/actions.test.ts
new file mode 100644
index 0000000..4ec6492
--- /dev/null
+++ b/src/actions.test.ts
@@ -0,0 +1,38 @@
+import updux from '.';
+import u from 'updeep';
+
+const noopEffect = () => () => () => {};
+
+test('actions defined in effects and mutations, multi-level', () => {
+  const {actions} = updux({
+    effects: {
+      foo: noopEffect,
+    },
+    mutations: {bar: () => () => null},
+    subduxes: {
+      mysub: {
+        effects: {baz: noopEffect },
+        mutations: {quux: () => () => null},
+        actions: {
+          foo: (limit:number) => ({limit}),
+        },
+      },
+      myothersub: {
+        effects: {
+          foo: noopEffect,
+        },
+      },
+    },
+  });
+
+  const types = Object.keys(actions);
+  types.sort();
+
+  expect(types).toEqual(['bar', 'baz', 'foo', 'quux']);
+
+  expect(actions.bar()).toEqual({type: 'bar'});
+  expect(actions.bar('xxx')).toEqual({type: 'bar', payload: 'xxx'});
+  expect(actions.bar(undefined, 'yyy')).toEqual({type: 'bar', meta: 'yyy'});
+
+  expect(actions.foo(12)).toEqual({type: 'foo', payload: {limit: 12}});
+});